In conjunction with the other chapters on Ar/Kr ion lasers, these sets of schematics can be useful for understanding the principles of operation of ion laser power supplies or for repair of a broken unit. While what are presented here aren't really complete plans, with a bit of effort, they can be adapted to a variety of ion laser tubes to provide any degree of performance and sophistication desired - from basic and simple to full featured with all sorts of bells and whistles.
Brief descriptions are also provided of the Lexel-95 PSU, Spectra-Physics 265 exciter with a 165-3 argon head, and a few other systems. Schematics for these may be added in the future.
See the Laser Equipment Gallery for for multiple detailed photos of several argon/krypton ion lasers and power supplies.
Note: For an explanation of the meanings of various designations like DC+, Boost, Tube-, etc., used in these schematics, see the section: Notation used in Ar/Kr Ion Laser Power Supply Diagrams and Schematics.
(Note 1) (Note 2) (Note 3) (Note 4) Desig- Power Regulation <---- Tube Voltage -----> nation Input Type Mode 80 90 100 110 | 180 220 Typical Heads ----------------------------------------------------------------------------- Omni-150 115 VAC S C/L ******** ALC-60X/Omni-532 NEC PSU 115 VAC S C/L ******** NEC GLG3030 SP-261 115 VAC S C/L ********** SP-162 Lexel-88 230 VAC L C/L ******* Lexel-88 SG-IT1 115 VAC N NA *********** (Note 5) SG-IX1 115 VAC N NA *********** " SG-IY1 115 VAC L C *********** " SG-IL1 115 VAC L C/L *********** " FS-IT1 230 VAC N NA *********** "
Notes:
Suitable transformers are not terribly expensive to buy new but can also be found in salvage yards associated with equipment like photocopiers.
Running a three-phase power supply on single-phase power entails additional problems since (as is shown below), much less filter capacitance - if any - is required using three-phase so the entire front end would have to be rebuilt to achieve adequate performance.
Laser manufacturers may also have connection diagrams for their systems. One example is:
One thing that may not be present when acquiring a laser head and power supply separately is the umbilical cable. These are very expensive if purchased new (assuming this is even possible anymore). However, they do turn up from various surplus places and on eBay, sometimes at more reasonable prices. And, if you're handy with a soldering iron, they can be built for under $50 from readily available components. The following applies directly to the cable having identical round connectors at both ends such as on the ALC-60X/Omni-532/543 but it should be possible to construct others as well. See the specific sections on the interconnect wiring for these lasers to determine minimum wire sizes for the high current conductors (filament and anode).
The connectors and pins for making a cable are AMP parts available on-line from Digikey. The cost of making a cable would be about $50. All the connections in the umbilical run 1 for 1 straight through, i.e., pin 1 is pin 1 at both ends.
You need 4 of the big female filament pins at about $7 each and two end shells at about $6 each and a bag of the smaller pins at about $15. You'll also need the mating remote connector body, about $6 also. Here are the part numbers for making the ALC-60X/Omni-532/543/etc. umbilical cable:
Shell: AMP type 206613, Series 4 CPC (Circular Plastic Connector) Size/contact arrangement 23-22M, standard sex-free hanging plug.
Pins:
These can be obtained from the major electronics distributors like Digikey, Mouser, Allied, etc.
There are also various types of information on other ion lasers systems that aren't nearly as complete but should be useful when attempting to get a laser operational or to repair one without complete manuals or documentation. This includes some laser head diagrams and interconnect wiring descriptions for several systems. Also see the section: Specifications and Pinouts for Various Argon Ion Lasers.
The Omnichrome 532 and American Laser Corporation 60X are functionally very similar (possibly identical for some versions). With the ALC-60X/Omni-532 being the most common argon ion lasers available surplus to the hobbyist, experimenter, or budding light show enthusiast, having a detailed schematic is a definite plus (what an understatement, huh?!). These circuit diagrams can also serve as the basis for a simple switchmode power supply design of your own! The Omni-150R can drive a variety of small Ar/Kr ion tubes requiring up to 10 A or so continuous current at 95 to 110 VDC - which covers most of the types of air-cooled tubes you are most likely to acquire. This would include the ALC-60X/Omni-532, Cyonics/Uniphase 2214 series, and many Spectra-Physics models. I expect that it can also power the NEC GLG3030 and other tubes requiring as little as 80 VDC (possibly limited to slightly less maximum current) but have no hard information on reliability when operating under these conditions. See the section: Running Ion Tubes with Lower DC Voltage Ratings on the Omni-150.
The Omni-150P is another version of this power supply with essentially the same specifications. It has a different PCB layout and there were a few modifications including the use of a commercial current sense transformer instead of the custom one used on the Omni-150R but it is nearly identical electrically. And, the MWK Laser Products model MWK-APS appears to be a virtual clone of the Omni-150 designs with only some minor simplifications (like the elimination of multiple taps on the filament transformer). Even most of the part numbers are identical. (I know that a complete schematics/parts list/PCB layout package for MWK-APS is available from MWK Laser Products but I don't know if they offer an assembled version.) Therefore, the Omni-150R schematics and descriptions that follow should be quite useful in troubleshooting either of these units.
The Laser Equipment Gallery has detailed views of various argon/krypton ion lasers including examples of the very popular 60 series from American Laser Corporation. However, note that the ALC and Omni models are plug compatible, the ALC power supply is NOT electrically or physically the same as the Omni-150R described below.
The diagrams are available in PDF format. There are three (3) separate sheets:
Due to some inconsistencies between the '150R' and '532' schematics that I used, some signal names and/or connectors identification may not match. I have attempted to correct these discrepancies where possible. However, this may have resulted in using names that were different than the 'official' ones in some cases.
Note that ALC's own power supplies are entirely different electrically from those from Omni. Only the heads and electrical interfaces are identical as per Xerox standards. Thus, these schematics (150/155) do not at all apply to an similar American product. Newer supplies have RS232 controls options and are power factor corrected.
The basic operation of the each of the major functional blocks are summarized below. For a more detailed discussion of the operation of the individual circuits, see the chapter: Ar/Kr Ion Laser Power Supplies.
RLY1 also enables the power supply fan and the igniter circuitry. (The fan in the laser head runs as long as SW2 is in the ON position.)
WARNING: For these line connected designs with a bridge rectifier, NO part of the circuit can be tied to earth ground (as is possible with a HeNe supply) for safety. Therefore, troubleshooting must be done with extreme care especially if no isolation transformer is used. Connecting the ground lead of a properly grounded scope to any part of the circuit will result in smoke or worse!
WARNING: ALL the power and some of the associated control circuitry is line-connected.
(From: Darren Freeman (daz111@rsphy1.anu.edu.au).)
The MOSFETS switch from DC+ to DC- (the full voltage across the main filter capacitor bank), so the voltage of the load is irrelevant. Whenever the freewheeling diode (D20 on the schematic) is conducting, the MOSFETs see the input voltage. And the average current through the MOSFETs isn't the same if the input voltage isn't the same. The *peak* current is equal to the load current, which will be the same. But the reduced duty results in the average current being lower, which is equal to the supply current. I expect that the tube voltage isn't a big deal to the PSU - the 240 V version can probably handle much higher tube voltages, maybe 250 V DC, with still the same current rating as before. But I haven't tried this as the control loop could still freak out.
In more detail: While the MOSFETs are on, the inductor (the sum of L1 and L3) sees the raw supply voltage (Vin) - Vload and the current ramps up a little bit, then the MOSFETs turn off and the current has to keep flowing (because of the series inductor which hates current changes) so the freewheeling diode (D20) conducts (and the MOSFETs see the full supply voltage). Now the inductor sees -Vload and the current ramps down a little. Then the cycle repeats. The effective voltage is roughly the duty-cycle times Vin, and with an inductor and capacitor that's roughly what you get out. The average current into the MOSFETs is the duty-cycle times Iout. It's like a transformer for DC, quite efficient. The MOSFET heating is due to resistive losses in the MOSFETs and also largely due to the transients during switching where the MOSFETs see current and voltage at the same time. As the frequency goes up, the switching losses start to dominate, but if you get better MOSFETs you can afford higher frequencies and smaller inductor/capacitor filters.
(From: Steve Roberts (osteven@akrobiz.com).)
Configuration on older units is done on the 22 pin remote connector (P1 on the Omni-532 laser head).
Usually you ground the current input if using light and vice-versa. The 150 and 150R can be configured each way. You also have a choice of using the head pot or the pot on the side of the supply, the supply pot is brought out on the remote connector, and if your not using the remote, you have to put a plug on the remote connector with jumpers. The CDRH requires a remote interlock jumper on Class IIIa and up so they use the 22 pin connector for that as well.
But most 150s only run light, and wiring them for current as per the book results in oscillation despite the book saying it can do either.
(From: Jerry (jbiehler@inetarena.com).)
"Larger Omni Ar/Kr ion laser heads like the 543 and 643 don't use a boost voltage for the igniter like the 532 but the anode voltage instead. On the ignite card, there is an opto-isolator that enables the igniter. This is controlled from a +15 volt signal provided by the PSU through pin 12 on the umbilical. The card inside the head has a connection to the current monitor connection and to the time delay circuit output. When you turn the laser on, pin 12 goes high (+15). When the timer runs out, the 15 volt signal to turn on the main relay also sends a signal to the card causing pin 12 to go low and fires the ignite card. Once there is current flow, pin 12 goes high when the card senses a signal from pin IC2-8."
For non functioning trigger modules, check the trigger capacitor (C8):
(From: Michael Herrera (mikeherrera34@msn.com).)
"I am an ex-Omnichrome laser and power supply tech. When I first started working for them, I noticed a high failure rate of trigger boards that I began to track. So I built a test model and began going through all the old PCB failures. I descovered that our vendor had been using 2 different suppliers for the trigger caps. One was yellow and the other was white. They both looked and worked the same except the yellow brand would yield a higher failure rate. I submitted an engineering change order (ECO) to our Engineer and he concured with my data. The ECO was approved and the vendor was notified to drop the yellow brand which in turn reduced our failure rate for that problem by about 80%. If I recall correctly the good vendor was SPRAUGE."
Although, not obvious from the head or power supply schematics, apparently, a failure of the light card can result in the laser operating at the power supply current limit even if it isn't wired for light feedback:
(From: Steve Roberts (osteven@akrobiz.com).)
When the Omni-150 slams to its current limit, the light sensor card in the head is malfunctioning. It is either misadjusted or needs both the opamp and the transistor replaced. A remote possibility is of course bad connections, but odds are the semiconductor parts on the light card are dead. They are exposed to heat and igniter pulses, and fail easily. I recommend using the metal cased versions of the 2N2222 transistor on the light card as they seem to do better then the plastic ones.
If there is no light feedback signal, the PSU defaults to maximum current, no matter how its controls are configured. Too much light feedback signal will cause the unit to oscillate, and too little will cause it to slam to max current. The potentiometer should be adjusted for 2.2 to 2.4 volts at maximum laser output.
Note: To get your system to run also requires a couple of jumpers on the remote connector (the other large round AMP thing). See the section: Omnichrome PSU Remote Connector Wiring.
(Portions from: Steve Roberts (osteven@akrobiz.com).)
(A version of this info is also acrhived at the LaserFx 60X Umbilical Pinouts Page.
ALC-60X/Omni-532 head cables are wired 1 to 1 pin for pin from the laser head to the power supply, there is no magic interconnect diagram for them.
However some of the wires require special attention:
The head cable should be limited to a maximum length of around 9 feet.
WARNING: These pinouts do NOT apply to NEC GLG3020, GLG3030, OR GLG3050 series heads even though they use the same connector. Connecting a NEC head to an Omni or ALC supply will result in PSU failure. Note that the compatibility issues go far beyond just the differences in pinout and CANNOT be resolved by simply rewiring the connector. See the section: Compatibility Issues of ALC-60X and NEC Laser Heads and Power Supplies for the gory details. :(
Umbilical Connector Pinout (The mating connector is AMP Part number 206612-1):
Pin Number Signal Description
-------------------------------------------------------------------------
1 Cathode/Filament (F1)
2 Head cover interlock (jumper to 5 if no head cover switch)
3 Safety Ground
4 230 VAC to head fan (see note 3)
5 Head cover interlock
6 Anode
7 Igniter enable (see note 3)
8 Light sensor common
9 Low end of 10K head pot (see note 4)
10 High end of 10K head pot
11 Boost (+250 to +500 VDC)
12 Current sense out
13 +15 VDC to light sensor card in head
14 -15 VDC to light sensor card in head
15 Wiper of 10K head pot
16 115 VAC Neutral to head fan
17 Boost via 100K resistor (see note 2)
18 Thermal protector/fan interlock (see note 1)
19 Light sensor feedback
20 115 VAC Hot to head fan
21 Thermal protector/fan interlock
22 Cathode/filament (F2)
Notes:
Important: laser heads with a built-in hardwired umbilical permanently attached use a different PSU and pin-out even though the connector is the same - consult the vendor/factory before use. The Power supplies designed for North American use will be missing pins 4, 7 and 12. Omnichrome power supplies can be jumpered to use either the control pot on the head or on the PSU. See the section: Differences Between Domestic and European ALC 60 Heads.
While the Omnichrome 532 and American Laser 60X are designed to be interchangeable, there are some differences. Omnichrome heads are designed to operate in light control mode and will not have a current sense pin on the 22 pin connector. The AC power LED on the head is powered by +15 Volts from the the light control card in the ALC 60X, but by -15 Volts in the Omnichrome laser heads. Some of the common 'clone' power supplies (e.g., those built by MWK (currently MWK Laser Products, formerly MWK Industries) do not support the light control cards and thus not all jacks on the side of the head will work. On the MWK PSUs, the Current jacks on the side of the head will still work, as will the overcurrent light, but the light jacks will not function as the light card is not used by the MWK supply.
The over-current LED is a relative indicator of tube current and was designed for use in a photocopier. When the laser is used in light show applications at currents up to the 10 Amp tube limit, this is NOT a true over-current warning. On ALC built units, you must press the button on the side of the head for the jacks to function.
Pinout for the 7 pin AC power connector:
This is used on the American/Landmark/Marlin "Gold Box" and Xerox PSU:
Pin Number Signal Description
-----------------------------------
1 AC Hot
2 AC Neutral
3 N/C
4 Safety/Earth Ground
5 N/C
6 AC Hot
7 AC Neutral
1 2
3 4 5
6 7
On the Gold Box power connector, pins 1 and 6 go to the 115 VAC Hot line (black wire), Pins 2 and 7 go to the 115 VAC Neutral wire (white wire), and pin 4 is Safety/Earth Ground (green wire). Pins 3 and 5 are unused and may not have any contacts installed.
One set of the AC power pins is the main feed which goes through a line filter on some versions and then to the main contactor contacts. The other two power pins go indirectly to a relay or directly to the main contactor coil, again depending on the model. Either way, the second set is for the on/off function only.
Omni PSUs need a remote interlock, Gold Boxes don't as they were designed as an OEM system and the printer or photocopier provided a interlock which dumped the 110 VAC relay which is on 6 and 7 of the AC connector. That's why there are 4 hot pins on the power connector - 2 of them are the main interlock. The 9 pin "barn" connector (it looks like a barn or house in side profile) is a passive interlock on every unit I've seen. It has 2 open collector optoisolators as outputs for "power on" and "tube lit", and one LED input for an optoisolater that forces standby - apply 5 to 12 VDC and it drops to standby. In other words, it lases unless you apply a voltage to that input. Here is the pinout:
Pin Number Signal Description
------------------------------------------------------------------------
1 Power on optocoupler (Q10) collector (out)
2 Power on optocoupler (Q10) emitter (out)
3 Tube lit optocoupler (Q8) collector (out)
4 Tube lit optocoupler (Q8) emitter (out)
5 Standby optocoupler (Q4) LED anode via 1 K (in)
6 Standby optocoupler (Q4) LED cathode via 1.1 K (in)
7 NC
8,9 Shorted together
All optocopulers are 6N25s. Each pin has a choke in series with it and a 0.1 uF ceramic cap to chassis ground. Q4 has a protection network of a 1N914 diode and a 0.01 uF cap across it.
Putting an optional on/off switch in series with pin 6 of the power connector will enable cool down of the laser after shutdown by those power supplies that have a fan shutdown timer. For other PSUs, this will just leave the fan and tube filament on when the unit is plugged in. The laser should have 2 to 3 minutes of fan cooling after shutdown, but no more, as this can lead to changes in the tube gas pressure and overstressed tube seals. For more details on fan installation, see the LaserFX Backstage Hobby Archives for a fan mount adapter to attach your favorite fan to the 60X.
The large AMP circular remote connector is soldered directly to a small PCB (as are some pins of the AMP umbilical connector as well) with P4 (which mates with J4 on the mainboard) and an unmarked 5 pin connector (which I call PX) which makes with the JX connector and cable for the current control pot and operate keyswitch. To select the way the power supply operates for current and light control, various pins need to be jumpered on this connector. Special prewired plugs were sold for this purpose (probably at exorbitant cost) but some female pins and jumpers or even just soldering directly to the male pins will work just fine.
Note that 5.1 V on the current drive input only results in about 5 A of tube current on some/many versions of the Omni-150 (including the one with the Omni-150R - Control Subsystem schematic referenced here where R25 is equal to 91K). Changing R25 to 39K (or paralleling the existing resistor with 68K) should result in a little over 10 A max. Alternatively, using higher drive voltage (up to about 10 V) from an external source) will result in proportionally higher tube current. It's possible that this was not corrected on these models since they were operated in light control mode for their original application. And, light control IS what should be used for maximum stability and tube life anyhow.
You also have to jumper pins 36 and 37 to complete the interlock chain.
The current and light drive inputs are just 0 to +5.1 VDC levels so an external source could be substituted for either or both pots and will provide the same range. CAUTION: I wouldn't recommend using this approach for modulation without confirming that the power supply's control loops remain stable at non-DC input frequencies! I do not know if this is the case.
(From: Michael Andrus (andrus@ccountry.net).)
"When wiring up the remote connector, you can monitor the current and output with out having to push the test button. By connecting pin 26 and any common pin to a meter with a 1V scale you can measure tube current. It is in (0.1 V)/A increments. By connecting pin 29 and any common pin to a meter with a 20 V scale you will get a 0 to 200 mW measurement. I believe this has a sensitivity of (0.1 V)/mW (not verified)."
Remote Connector Pinout Pins that are not listed are not physically present in connector shell. P4, PX, and Umb. Pins show where else these signals go inside the Omni-150.
Remote Pin -> P4 Pin PX Pin Umb. Pin Signal Description
-----------------------------------------------------------------------------
1 7 Common (Analog Ground)
2 3 Wiper of PSU (current ctrl) pot
3 8 Light (drive) In
4 15 Wiper of head (light ctrl) pot
5 5
6 6 Current (drive) In
8 3 Safety Ground
9 1 2 High end of current control pot
(connects to 5.1 V reference
via P4-1)
23 7 Common (Analog Ground)
24 13 14 -15 VDC
25 12 13 +15 VDC
26 2 Current sense out
27 7 Common (Analog Ground)
29 4 Light sense out
30 7 Common (Analog Ground)
34 3 Remote standby switch
35 13 14 -15 VDC
36 2 Interlock chain to head
37 5 Operate keyswitch (other end
goes to P4-14 via PX-5)
Function Pin Numbers Comments
-------------------------------------------------------------------------------
Standby Mode Pin 4: Standby input Pin 12 is at -15 VDC. To run in
Pin 12: -15 VDC Standby Mode, jumper pin 4 to
pin 12.
Operate Mode Pin 4: For Operate Mode, leave open.
Laser Power Pin 8: Power Mon "n"V/mW where n equals 5 divided
Monitor Pin 11: Ground by the calibrated maximum output
of the laser head.
Laser Current Pin 9: Current Mon 100 mV/A. Range 0 to 1.2 V.
Monitor Pin 11: Ground
Current Control Pin 6: Ext. Cur. Input Jumper pin 6 to pin 18.
Mode Pin 18: Pot wiper out Pin 18 is the power supply pot.
For external input, calibration
0.1 V/A, 6 V max. 10K Zin.
Light Control Pin 7: Ext. Light Input Jumper pin 7 to pin 18.
Pin 18: Pot wiper out Pin 18 is the power supply pot.
Beam Interlock Pin 1: Beam Interlock Out Jumper pin 1 to pin 3 to complete
Pin 3: Beam Interlock In interlock circuit.
The beam interlock is used to insure that all cables and cooling fans are
connected before the beam can be activated. Breaking this interlock cause
the beam to go off but the head fans will stay on. A red LED on the power
supply front panel signals that the interlock is broken.
DC Power Supplies Pin 12: -15 VDC 100 mA max.
Pin 13: +15 VDC 100 mA max.
Circuit Ground Pins 11 and 16: Ground Common circuit ground.
Chassis Ground Pin 25 Earth Ground
Voltage Reference Pin 17: 5.1 VDC
Safety Interlock Pin 19: Interlock Out Jumper pin 19 to pin 21 to
Pin 21: Interlock In complete the safety interlock
circuit.
The safety interlock is connected to the main power relays. Before the
safety interlock can be activated, all cables and connectors must be plugged
in and the cover of the power supply must be closed.
PSOK Signal Pin 23: Signal return
Pin 24: +5 VDC
The minimal jumpers for normal operation: Pins 1 to 2 (Beam Interlock), Pins 19 to 21 (Safety Interlock), and pins 7 to 18 (Light Control Mode using power supply pot).
The following are the KNOWN DIFFERENCES from the normal 60X pinout for the American Laser 60C/60B heads normally sent to Europe.
I have one setting here for a retubing and decided to find the what was needed to hook it up to my supply. Connecting these to a normal 60X supply will result in either a nonstart due to lack of interlocks or a explosion, depending on model of supply used.
How to tell if you have a 60C/60B - physical differences:
Lasers sent to Europe often use a 3 kW step down transformer to run off 220/240 VAC, 50 Hz.
60B/C Connector wiring:
(From: Steve Roberts (osteven@akrobiz.com).)
I have it from good authority that the difference between the 115 VAC and the 230 VAC version is changing the taps on the transformers, rearranging the main filter capacitor bank to a series/parallel combination, and replacing a couple other parts. Said good info is from 2 Omni owners, one with a 543, which is the 300 to 500 mW version with a stretched tube and a huge gas reservoir.
Here are the details:
Everything else is the same for the both power supplies.
(From: Pasi Arffman (pasi.arffman@otol.fi).)
I was told that the 230 VAC version of this PSU (Omni-151) has 4 MOSFETs instead of 2 (2 pairs of 2 wired in series, then paralleled using 2 driver transformer circuits that are identical to the those in the Omni-150R, the drivers being fed by the same control signal) and the other transformers (control, filament) with 230 V primary windings. Also a better voltage rating for the chopper components.
(From: Sam.)
This may have been a one-of-a-kind hack job, who knows? Sounds like a kludge. It's obviously much more complex than needed. It would appear that the Omni-155 is the official 230 VAC version.
The Omni-155 is one of the versions of the Omni-150 power supply designed to run on 230 VAC *only*. However, it is possible to convert it to 115 VAC with a modest investment in $$$ and effort. This conversion assumes that the Omni-155 works in the first place on 230 VAC!
However, before proceeding with what will be a rather involved process - especially if you're not handy with a soldering iron - consider that using an Omni-155 as-is with a high current step-up transformer may still be cheaper and definitely much easier and lower risk, unless portability is a primary requirement. :)
If you decide to go ahead with the conversion, here is the general procedure:
Again, make notes of what you un plug and where they go.
Side note: CAUTION/patience/yikes! These CAD-drawn circuit boards are a pain to unsolder for the holes seem to be the same diameter as the part lead going through as well as most of the part leads were tightly folded over before they were originally soldered. If not careful, you will pull the entire via stack through and part of the trace off the board with the part. :-(
It seems that the 155's are really 150's modified for 230 VAC and re labeled 155.
Take the capacitor board from the heat sink and remove and re solder the two caps (1,000 uF/200 V) so they are all in parallel and match the + and - signs on the board. Remove the bleeder resistors. Use original jumper wire on back of board. Cut in half and strip and jump the two notch cuts in the board. This will make a 4,000 uF/200 V capacitor as in the 150.
With the advent of DPSS, I refuse to pay big $$$ for one of these Omnichrome supplies. :-) $700 to $900 is sheer madness! The Omni 155 appears and does on the average of 50 to 70 dollars and the conversion cost still keeps it under $150.
At the time of this writing my converted 155 has been running at 8 A for about 5 hours without a hitch. I stuffed the board in a 150 chassis with its filament transformer for the test. And I haven't replaced C11, C12, and C13 yet. Just couldn't wait. :-)
I will however replace them when they come in for more filtering the better.
I (Dave) have acquired a large lot of MOSFETS for these supplies as well as the fast recovery diode, and am willing to repair these for a fair price on a case-by-case basis. I do not have the room here to do this on a regular basis. Since I have been focused on these, they are actually very simple to fix. If your unit's L2 is melted down, this might not be a fix for me for this part cannot be had without buying another unit. Other than that, let me know.
Unlike a power supply using a linear regulator where power dissipation is huge and proportional to the difference between the rectified/filtered line voltage and the tube voltage, and even thinking about this would be out of the question. For argon ion tubes like the NEC GLG3030 and some Spectra-Physics models which may drop to as little as 80 VDC when in good condition, even less at end-of-life (low pressure) and the voltage drop across the pass-bank will increase by 15 to 25 V compared to a tube like the ALC-60X.
However, with a switcher, the limiting factor will likely be the maximum voltage drop that the MOSFETs in the chopper can safely control and it would appear that for the Omni-150 and similar designs, this is not dependent on the tube voltage but is the voltage across the main filter capacitor bank.
My expectation is that running an Omni-150 with a lower voltage tube won't cause serious problems for the supply since the European version of the Omni-150 uses the same type MOSFET and it is switching about 150 V more (see the previous section). For a given tube current, the average current through the MOSFETs will be the same but the duty cycle will be lower. Their power dissipation will probably increase slightly but this would only be of consequence when running near maximum output current.
Whether this can be done without some critical readjustments I don't know. The startup duty cycle (which runs open loop) may need to be reduced and other adjustments will almost certainly be needed. And, it is extremely easy to destroy expensive parts like the MOSFETs if something is not set properly or a pot is turned too far. Thus, I really don't recommend attempting this unless you have a copy of the complete Omni-150 manual containing the adjustment procedure (or a bag of replacement MOSFETs!).
Steve Roberts apparently once saw a client run an NEC tube from one of these without blowing up either the power supply or tube but it was only for 30 seconds (though he did mention something about the tube appearing to undergo nuclear fusion)!
Unlike many other ion laser power supplies, these seem to always fail the same way. The difficulty comes from the way their case and PCB are made. When you have a dead one, my bet is that both MOSFETs, the fast recovery diode, one capacitor, and the +15 V regulator are dead. Replace these and you are off and running. 90% of the fail from 3 causes: MOSFET failure, miswiring, or a loose heatsink that breaks off the MOSFET leads where the cooling fan vibrates the poorly mounted heatsink.
(Refer to the sections starting with: Omnichrome 150R Power Supply and 532 Laser Head (Omni-150R/532) for the schematics.)
WARNING: For any testing, DON'T measure across the tube anode itself (past the igniter transformer) while the igniter is pulsing - your meter will likely be destroyed!
At the same time, the main filter capacitor bank is slowly charged via a separate rectifier diode and current limiting resistor. Typically, it will reach about 130 VDC by the time the preheat timer expires.
At the same time, the Boost multiplier is enabled ramping up to 400 to 500 V across the SCR (Q3) on the igniter PCB in the laser head (and this plus the 160 VDC across the tube). The voltage on the Q3 will dip to near 0 V and charge back up each time the SCR triggers.
Thus, if you are monitoring the voltage between the SCR anode and the tube cathode when the system is switched on, the voltage should slowly climb to about 130 V, then jump to around 160 V and ramp up toward 500 V. At some point, the UJT will trigger resulting in a dip in voltage and the 'tick' of the igniter. The voltage will then climb back up and the cycle will repeat until the tube starts or something dies. :(
If the voltage doesn't go above about 160 VDC, the Boost source is not working and the igniter will never be trigger.
To determine where the problem is located, it should be possible to run the power supply with no laser head attached as long as the interlock chain is complete and then carefully measure voltages at the end of the umbilical cable. See the sections starting with: Omnichrome PSU to Laser Head Interconnect Wiring. If Boost and Boost(100K) are missing, then the fault is probably in the power supply. Otherwise, check components on the igniter PCB in the laser head.
There isn't much to the quadrupler in the power supply and if a bad part is found almost any reasonable combination of 1N4007 diodes and caps from your junk box should work for testing at least. However, I'd quicker believe such a failure is due to a bad connection or wiring problem than a blown component. In fact, there is a 3 pin connector in the power supply (J8 on the connector PCB) which is used for both Boost voltages, Boost and Boost(100K). Check to see if it is unplugged - perhaps someone before you was using the power supply with a laser head not requiring a boost voltage for starting and unplugged it to avoid getting zapped! Possibilities in the laser head include a shorted blocking diode (D1), or the SCR itself or nearby components.
For more info, see the sections starting with: Ion Laser Power Supply Repair. Some of the material there was taken directly from the Omni-150 service manual.
Note that this is specifically for the Omni-150R. Your mileage may vary if attempting to use it for other versions.
There are two versions here - Rev B and Rev C. These are likely the forerunners of the Omni-150R, above. They have similar characteristics but the implementation differs significantly from the Omni-150R and Omni-150P, and there are more than just trivial differences between the Rev B and Rev C.
This schematic and the accompanying description may also be found on Martin Whybrow Laser Page.
The schematic does not show the low voltage power supplies (+/-12 VDC for the isolated circuits and +/-15 VDC for the non-isolated circuits) as these are simple linear regulator based supplies fed from 2 independent windings on the power transformer. Also not shown are the HT rectifier and associated 3 x 2,200 uF filter capacitors and inductor, the boost supplies, the filament (cathode) transformer or the pre-heat delay circuit as these are all near identical to those in the Omni-150R power supply (and I couldn't fit them onto a single A3 drawing sheet!). All component references are my own as the PCB has no component references anywhere. Note also that the function references next to the 5 preset pots have been deduced from the circuit and some may be incorrect.
The circuit is split into two sections: the isolated external loop which is connected to the remote interface connector on the front of the PSU and the non-isolated inner loop which is connected to the HT (AC line) supply. The two loops are linked by opto-couplers OK1 and OK2.
Inner loop:
Initially the outer loop is inactive and all regulation takes place within the inner loop, this is also the case when the power supply is set to standby mode via the remote connector. R47 is in series with the anode of the laser tube, when current flows, the current mirror consisting of Q1 to Q5 produces a voltage across 100 ohm resistor R51, this is approximately 130 mV/A of tube current. This monitor signal is fed into IC3d which then drives opto-coupler OK2 which feeds the current signal into the isolated outer loop. The current signal is also fed into the feedback amplifier consisting of IC3c, IC3a and associated components. This amplifier has a flat frequency response between 0 and 1 Hz, and then rolls off by 3dB to 10 Hz and is flat again to 10 kHz where it then rolls off at 3dB/octave. Diode D8 appears to be present to clip the signal should fast transients appear in the current signal. Without the diode installed, the tube and power supply become unstable above 8 A (more on this later). IC3a is AC coupled and feeds the noise component of the tube current back to the first amplifying stage via R28, the noise control adjustment. R27 sets the standby current to, nominally, 4 A. R26 controls the gain of the circuit when regulating on the outer loop. OK1 is initially switched off so the top of R26 is nominally 0V therefore the feedback amplifier output depends only on the setting of R27 and the tube current signal. The feedback signal output from IC3c feeds into one of the error amps in IC4, a TL494 SMPS controller; IC4's outputs are in parallel and drive IC5, a DS0026 MOS inverter/driver which, in turn, drives the MOSFETs Q6 to Q8. As a result, IC4 is operated in an unusual inverted mode whereby the switching FETs are conducting when the output of IC4 is off, so the feedback signal goes into the non-inverting input of the error amp. The internal oscillator of IC4 runs at 100 kHz, determined by R54 and C18. And because the output control pin is grounded, the PWM output from the device is also at 100 kHz. Note that the ground of IC4 is connected to the -15 VDC power rail not 0 V. This means that the operating region for regulation is when pin 16 is between -11.5 V and -14.5 V. When the voltage here is more negative than -11.5 V, the outputs of IC4 switch off causing the FETs to switch on and thus send maximum current through the tube; this current is limited only by the internal resistance of the HT supply circuit, the Rds of the FETs, the 2 current sense resistors (1 in the laser head) and the cabling resistance.
Prior to tube ignition, IC3c's inverting input is negative with respect to the non-inverting input. The actual voltage depending on the setting of R27. IC3c runs open loop at DC so the output swings to the +15 VDC rail therefore causing the switching FETs to be turned on. This protects the FETs from any stray transients from the igniter circuit and the high di/dt waveform through the inductors. When the tube strikes, the current very rapidly rises to around 25 A, then falls slightly to about 18 A. As a result, the current monitor signal is at around +2.3 V and IC3c's inverting input now becomes positive with respect to the non-inverting input, therefore the output of IC3c starts to fall to the -15 VDC rail at a rate largely determined by C8 as D8 is now conducting and damping the response of IC3c (see starting problem below); when the voltage reaches -11.5 V the SMPS starts to regulate and the tube current reduces until the inverting input of IC3c reaches 0 V, the PSU is now in closed loop control at the standby current.
Outer loop:
The current monitor signal, isolated by OK2, feeds into the current signal amplifier IC2d whose gain is set to produce 100 mV/A of tube current. This signal feeds out to the remote current monitor, pin 26, of the remote connector and also into IC2b. IC2b is a threshold comparator with its inverting input held at +180 mV derived from 9.1 V zener diode D4 with R23 and R21 acting as a potential divider. When the inverting input becomes higher than +180 mV (1.8 A of tube current), the output of IC2b goes high causing the current detect signal, pin 12, on the laser head connector to go to approximately +14 V via diode D3. This signal is not used in the ALC60X or Omnichrome 532 head, but is used in larger models, particularly krypton filled types. IC2a acts as an integrator with a time constant determined by R19 and C5; when IC2b's output goes high, the output of IC2a will go low approximately 100 ms later, this pulls the cathode of OK1's LED low and enables OK1 thus putting the PSU into outer loop regulation. OK1 can be disabled by putting the remote standby input, pin 34, on the remote connector to a voltage of less than 0 V (e.g., -12 V on pin 24), thereby putting the PSU into standby operation at approximately 4 A of tube current.
IC2c forms a reference voltage source that supplies the front panel power control pot and the power control pot in the laser head with a +5.1 VDC reference, adjusted with R23.
The current signal from IC2d is also fed into comparator IC1b where it is compared to the voltage across R11. R10 and R11 form a potential divider reducing the 1 A/V current control signal on the remote current control (pin 6 of the remote connector) to 100 mV/A. Therefore, when the current in the tube exceeds the current set at the remote current control input, IC1b's output goes low. R9 and C2 reduce the HF gain of this stage to improve stability.
IC1c amplifies the light output signal from the laser head's optical pick-up and this signal is then fed out on the remote light output, pin 29, on the remote connector. The light output signal from the laser head also feeds into IC1a where it is summed with the inverted remote light control signal from IC1d, thus when the light output of the laser exceeds the level set at the remote light control input, pin 3 (or pin 5), on the remote connector, the output of IC1a goes low.
IC1a and IC1b are connected, via diodes D1 and D2 respectively, to the anode of the LED in OK1. When either (or both) IC1a or IC1b's outputs are high, current flows in OK1 causing the voltage across R25 in the inner loop to become negative. This voltage feeds into the feedback amplifier IC3c where it increases the current demand thus increasing the duty cycle of the switching FETs. As the duty cycle of the FETs increase, the light output and current in the tube rise until both IC1a and IC1b's outputs go high again, thus regulation is achieved via the outer loop. Current or light control modes can be used by leaving the unused input open or the two modes may be combined by supplying drive signals to both inputs, whichever is set highest will take control.
Starting problem on my Omni-150:
I am having a problem running known good laser heads on this power supply. When the tube first ignites, the current very rapidly rises to a high value for approximately 1 ms; if the current remains at this high level, around 18 A, the plasma is highly unstable and the discharge is blown out, Chart 1 shows a typical ignition current waveform. The problem is that the current demand signal at IC4 pin 1 falls very slowly as a result of D8 in the feedback loop of IC3c, taking 35 ms to reach the regulation region of -11.5 V to -14.5 V (Chart 1 shows the control signal with the control loop modeled in Spice), therefore the arc becomes extinguished before the PSU goes into regulation. Removing D8 causes pin 16 to reach this region in less than 200 us as measured with my oscilloscope (the Spice model shows closer to 650 us, see Chart 2) and the tube ignites first time every time, but if the current is increased above 8 A, the plasma becomes very unstable and the power supply breaks into oscillation resulting in rapid current rise and, usually, the plasma extinguishing. If anyone has a suggestion as how to improve the stability of the loop without compromising the time it takes to start regulating, please contact me via the email address above. Thanks.
This schematic and the accompanying description may also be found on Skywise's Laser and Optics Reference Page.
Usually they say MARLIN Landmark on them, but one way to tell is to drive your laser to 11 amps. If successful, you don't have a Landmark, they melt at 9.5 A. :) These have a smaller narrower box then the traditional X supply. I'll try to get measurements and a schematic one of these days.
The other 5 pin umbilical connector on the PSU is for remote standby. If you trace the wires on the card, one is the open collector transistor output of a optocoupler that says the unit is lit. The other is a led in a optocoupler that puts the unit into standby for cool-down/idle. The opto has two 1K ohm resistors in series with it, so you just apply enough voltage (5 to 9 V) to light the opto while keeping the current to between 2 and 3 mA to avoid burning out the LED,
This is a well supported unit. The tube is all glass and will do between 5 and 30 mW, depending on its condition. If it is the standard NEC power supply, there will probably be a laser power meter and adjustable current/light controls on the front panel, so you may run it at a very low power to maximize its life and keep it reasonably eye-safe. It can be dialed down even lower - to class II or IIIa (laser pointer) power levels by detuning the cavity a little for additional safety. (The tube has internal mirrors but with some amount of external adjustment range.)
The NEC GLG-3030 is suitable for displays, fluorescence experiments, small laser shows, measurements, Michelson interferometers, exposing gelatin to harden it, and a couple of years of science fair projects. Just don't expect to burn the walls or anything else with it. The laser runs on 115 VAC at a maximum of 13 A line current and at a maximum of 9 A of tube current.
Caution: While the same umbilical connector is used for both the NEC-3030 and ALC-60X/Omni-532, THEY ARE NOT COMPATIBLE AS WIRED! It is likely that the power supply (at lest) will be damaged if you attempt to power an NEC head from an ALC/Omni PSU and vice-versa! Note that the compatibility issues go far beyond just the differences in pinout and CANNOT be resolved by simply rewiring the connector. See the section: Compatibility Issues of ALC-60X and NEC Laser Heads and Power Supplies for the gory details. :(
The diagram is available in PDF format:
The basic operation of the each of the major functional blocks are summarized below. For a more detailed discussion of the operation of the individual circuits, see the chapter: Ar/Kr Ion Laser Power Supplies.
I found an almost identical igniter in a more modern NEC GLG3059H-H laser head. Except for some trivial differences in part values, it is what's inside the dashed lines labeled "Trigger Circuit", with the cathode of CR301 tied to R306 directly since there is no "Ionized Sensing Circuit".
Together, this information should enable you to construct a cable between your power supply and laser head or understand the wiring of an existing cable. However, read this section in its entirety to make sure which portions apply to your particular models.
Some of the wires in the umbilical require special attention:
The head cable should be limited to a maximum length of around 9 feet.
WARNING: These pinouts apply to NEC GLG3020, GLG3030 OR GLG3050 laser heads. They DO NOT apply to ALC/OMNI series heads even though the same connector is used. Attaching an NEC head to an Omni or ALC supply will result in PSU failure. Note that the compatibility issues go far beyond just the differences in pinout and CANNOT be resolved by simply rewiring the connector. See the section: Compatibility Issues of ALC-60X and NEC Laser Heads and Power Supplies for the gory details. :(
Umbilical Connector Pinout (The mating connector is AMP Part number 206612-1):
Pin Number Signal Description
----------------------------------------------------
1 Cathode/Filament (F1)
2 Head cover interlock (jumper to 5)
3 Frame/Earth/Safety Ground
4 No connection
5 Head cover interlock (jumper to 3)
6 Laser tube anode
7 No connection
8 Shield/low voltage ground
9 To output control (Out1)
10 To output control (Out1)
11 No connection
12 No connection
13 +15 VDC
14 -15 VDC
15 To wiper of output control
16 115 VAC Hot
17 No connection
18 Thermal protector return
19 Light sensor feedback
20 115 VAC Return (Neutral)
21 Thermal protector
22 Cathode/filament (F2)
The remote connector pinout and signal description are provided in the section: SP-261B Remote/Interface Connector.
Also see the section: Specifications and Pinouts for Various Argon Ion Lasers.
(From: Steve Roberts (osteven@akrobiz.com).)
I just did a little staring at the the schematic. Something they neglect to mention in the NEC manual is that there are opto-couplers in the interlock circuit, on the interface card, and these are used to isolate external standby and interlock signals. What they didn't mention is there are jumpers inside the supply, to power up the LEDs used in the opto-couplers. So depending how the jumpers are set, it either needs external 12 to 15 V to light the LEDs and fire the unit up (jumpers removed), or a just a short across the interlock and standby pins (jumpers installed). Hence the insanity caused by some people's units not firing up, while others do. Also it needs the fan wired through the head connector to power the interlocks on some units, using a external fan voltage direct from the wall may not work.
Talk about a stupid thing to omit from the manual - a two configuration connector! I'm NOT nuts, and they are both right. The same pins are used for the interlock and standby, they just can be configured either for a short or a external voltage to close the circuits.
A complete operation manual for these lasers can be found at Cyonics/Uniphase 2200 Series Argon Ion Laser Operation Manual.
The 2201-40MLA uses a tube like the Cyonics/Uniphase Model 2301 Internal Mirror Ion Tube. The CU-2201 Interior View shows the 2301 ion tube, Start PCB at the top of the photo and the Light Sense PCB at the right by the output aperture.
Powering this unit should be even easier than the model 2214 since in addition to no requirement for a boost supply, the starting is automatic so there is not even any need for an external enable signal. See the section: Cyonics/Uniphase Model 2214 Laser Head (CU-2214) for more information keeping in mind this difference.
Normal tube voltage should be in the 90 to 95 V range at 8 A.
This is the umbilical wiring for a Cyonics/Uniphase 2201-40MLA laser head.
Pin Number Color (Size) Signal Description
------------------------------------------------------------------------
1 Yellow (big) Filament 1
2 Orange (mini) Tied to pin 5
3 Green (med) Chassis ground
4 -- NC
5 Orange (mini) Tied to pin 2
6 Red (med) Starter board P2-IN with pin 7 (DC+)
7 Red (med) Starter board P2-IN with pin 6 (DC+)
8 Black (med/mini) Light control board and starter board
9 Green (med) Chassis ground
10 -- NC
11 -- NC
12 Violet (mini) Starter board
13 White (mini) Light control board
14 Black (mini) Light control board
15 -- NC
16 Brown (mini) Hour meter
17 -- NC
18 Orange (mini) Thermal interlock switch
19 Red (mini) Light control board
20 Blue (mini) Hour meter
21 Orange (mini) Thermal interlock switch
22 Yellow (big) Filament 2
(From: Nick Andrews (nicothefabulous@hotmail.com).)
My starter board is slightly different than the schematics, above. It is a revision J, marked CH937-104 and is simpler than the Rev 6 board, lacking everything to the left of R10 (470K, connected to U1).
(From: Sam.)
For this version, it must be the responsibility of the power supply to disable the starter once the tube is running, or else it just keeps pulsing forever!
There is a complete copy at LaserFX Copy of Cyonics/Uniphase Model 2001 Argon Ion Laser Systems Manual but here is the basic remote panel, equivalent to the one for the 2114, below.
(Portions from: Werner Bleckwendt.)
These power supplies do not have personality boards. The LEDs inside the unit have the following meanings:
Testing the PSU without a head connection won't damage anything but you'll need to close the interlock chain and provide dummy loads for the filament and tube. CAUTION: The dummy load for the filament can be a suitable length of wire that matches the resistance of the hot filament. However, for the tube, using a resistor may result in smoke since it expects the tube voltage drop. Leaving the anode circuit open is probably OK for quick testing of the anode and start voltages as this is similar to attaching a head with tube that won't start.
Note: A "2" in the second digit of the model denotes laser or laser head while a "1" denotes power supply and "3" denotes the bare tube (though I don't know if the other numbers are identical for the bare tube).
A complete operation manual for these lasers can be found at JDS Uniphase 2010 series Argon Ion Laser Operation Manual.
Note: To remove the mounting ring assembly that may be present on some of these lasers non-destructively, unscrew the 6 hex studs, loosen the 8 Allen (hex) set-screws (4 around the outside of each stainless steel ring), and unbend and pull out the two steel strap ends and and/or cut them off. Then, slide the inner and outer rings off of the front of the laser head taking care not to scratch the fabulous paint job. :) Finally, peel off the two strips of protective polyimide tape.
The 2214-30SLT and 2214-20GL use a tube similar to the Cyonics/Uniphase Model 2301 Internal Mirror Ion Tube except for the slightly different mounting/heatsinking arrangement and lack of shroud (I didn't disassemble the heads I had access to quite far enough to read the label!). The igniter is inside the plastic 'wart' visible in the photo of the intact laser head. The essential blower mounts on the rear. A shop-vac (clean and with filter in place) set to suck can probably be used for testing. :)
It is trivial to power these lasers from any sort of argon ion laser power supply suitable for 100 to 110 V tubes including all of the designs given in this chapter. The only required connections are for the filament/DC- and DC+. There is no need for a boost source as the igniter operates from DC+ alone and Cyonics/Uniphase tubes practically start on their own in any case. Starting is initiated via an opto-coupled DC enable signal (anything between 9 and 15 VDC should work). The head includes a sensor and preamp to provide the light feedback signal.
I used SG-IX1 to test one of these units with the suction connection (with flower pot hose adapter) of a vacuum/blower from a defunct 9 track tape drive for cooling. A 9 V battery enabled the starting trigger - just connect until the tube lights up or leave on to restart automatically if needed. The tube voltage on this particular sample was correct at around 105 V, not varying much for the 3 current settings produced by SG-IX1: 3, 4.5, and 7 A. (The 3 A setting is marginal - the current gradually dropped to 2 A over the course of a few seconds (with rising tube voltage) at which point the discharge went out, worse when hot. This appears to indicate a negative resistance region of the discharge characteristic which should be avoided since it is hard on the cathode.) Note that these currents are slightly lower than when running SG-IX1 with may home-built Cyonics laser head indicating a slightly higher tube voltage (which may mean a newer/lower mileage/healthier tube.) Slight adjustment to mirror alignment was indicated - it wasn't far off but reduced power quite significantly. Gently rocking the rear mount with a close-fitting cardboard tube or pressing on the front mount with a wooden stick was enough to peak the output power! Locking collars would be more than adequate to adjust alignment but they were missing from this tube for some reason. I later added locking collars from a defunct Melles Griot HeNe laser tube and was able to tweak the power up to almost 30 mW at 10 A. Adjustment of only the one at the cathode-end was sufficient to achieve this power increase; doing them both might get a bit more. Adding the locking collar at the cathode-end is trivial but the one at the anode-end requires removal of the light sensor PCB and its mounting plate - more disassembly than I would have liked. It's in there now and could be adjusted if I find myself with absolutely nothing more interesting to do. :)
The diagram is available in PDF format:
The basic operation of the each of the major functional blocks are summarized below. For a more detailed discussion of the operation of the individual circuits, see the chapter: Ar/Kr Ion Laser Power Supplies.
These pinouts were reverse engineered from a 2214 laser head. THERE MAY BE ERRORS - Use at your own risk!
Power Connector:
This is a 9 pin AMP Universal Mate-N-Lock male shell with male pins. Here is the pinout (view from front of the connector on the end of head cable):
6
.-------.
3 |D O O| 9
2 |O O C| 8
1 |D O O| 7
+-------'
4
Pin Number Signal Description Cable Wire Color
-----------------------------------------------------------
1 DC+ Black
2 Case/Earth Ground Green/Yellow Stripe
3 Cathode/Filament (F1) Yellow
4 No Connection
5 Case/Earth Ground Green/Yellow Stripe
6 Cathode/Filament (F1) Yellow
7 No Connection
8 Cathode/Filament (F2) Blue
9 Cathode/Filament (F2) Blue
Control/Light Feedback Connector:
This is a 14 pin medium size circular male connector (much smaller than the type used in the ALC/Omni/NEC lasers). Here is the pinout (view from the front of connector on the end of the head cable):
1 2 3
4 5 6 7
8 9 10 11
12 13 14
Pin Number Signal Description Cable Wire Color
--------------------------------------------------------
1 +15 VDC White
2 Start+ (See text) Fat Purple
3 Signal Ground Dark Green
4 Interlock 1 Orange
5 -15 VDC Black
6 Start- Fat Dark Green
7 Signal Ground Blue
8 No Connect
9 No Connect
10 No Connect
11 Light Feedback Red
12 Interlock 2 Orange
13 No Connect
14 Signal Ground Dark Green
Note: According to my manual, the 211xA supplies will only work on 100 or 120 VAC and the 211xB supplies are for 200, 208, 220 or 240 VAC. The 211x (without an A or B) can be strapped for 100, 120, 200, 208, 220 or 240 VAC. The 211xP will also work on any voltage and can be changed without opening the case. So, double check to be sure the version you are considering will work with your power! Make sure your branch circuit can handle the load (12 A or more at maximum tube current at 115 VAC) without sagging too much. The power supply may buzz/whine on low line voltage. While the laser will still work, this may be stressful for it the power supply. A dedicated circuit close to the service panel would be best.
The Uniphase model 2114P and other similar power supplies a pair of mating connectors for the cylindrical 2214 laser head (a square 9 pin AMP Universal Mate-N-Lock connector for power and a round 14 pin connector for control/light feedback. See the section: CU-2214 Interconnect Wiring for details.) In order to operate the laser, some simple circuitry is needed for the DB25 "User Interface" connector as described in the next section.
There are two remote interfaces listed on the Web site, above. The model 2501 has some switches and knobs (no display) while the model 2500 has soft touch buttons and a built-in digital display. Note that based on the wiring and mounting arrangement, the Spectra-Physics 361D remote interface should be compatible with these power supplies (though I have not yet confirmed this). It is somewhere in between the 2501 and 2500 with knobs and toggle switches but a digital display.
I built a remote control panel that is similar to the simpler model 2501 except that I included a digital panel meter rescued from the trash so current or power output can be monitored independent of the mode of operation. It has separate pots for current and light control, a keyswitch for "Discharge On" (becuase I had one from a defunct PC case!), and attaches via a 3 foot cable. Everything is installed in a nice recycled aluminum box. :) Unless you're in love with digital controls, there is not much additional benefit to having the model 2500. In fact, mine is functionally identical to the Spectra-Physics 361D.
Here's the schematic for another almost identical control panel: Kevin's Uniphase 211X Ion Laser Control Panel. (Note: The functions of pins 8 and 9 are swapped and not everything else has been totally verified. I have fixed the swapped pins on Kevin's Uniphase 211X Ion Laser Control Panel.) Mine has a hardwired interlock and uses the keylock switch for Discharge On with the Emission LED tied to that as well, erring on the side of caution as the LED will be on as long as the switch is on. Since the LED DPM also requires more current than the 211X connector can supply, my control panel must be plugged into a wall adapter if the DPM is to be used. But it is otherwise functionally identical to Kevin's.
The circuit below is even simpler but adequate:
(From: Chris Leubner (cdleubner@ameritech.net).)
I am lucky as I have a remote that goes to it, but I also have the manual for these power supplies too and it is not much more then a DPDT switch, one resistor, and a 1K ohm pot. :-)
Pin 1 o-----o Pin 3 (Interlock)
(+15 VDC) Pin 13 o---+-----o Pin 2 (Enable)
|
| Idle/Run
(Run) +-----o
\
o---o Pin 4 (Idle/Run)
(Idle) +---o
_|_
-
1K 1.5K
Pin 13 o---+------/\/\--------/\/\/\----+
(+15 VDC) | CW <- ^ _|_
| | -
| |
+---o | o----o Pin 7 (Light Mode)
\ | /
o---o Pin 5 +----o DPDT Current/Light Mode Select
(Current/Light)
+---o o----o Pin 6 (Current Mode)
_|_
-
Note: Pins 10, 11, 14, 20, 21, 22, and 24 are _|_
-
This circuitry and a digital voltmeter sums up the remote control head. I wonder what they charged for it? :) (They did add a couple more switches and separate pots.)
(From: Sam.)
The absolute minimalist wiring to see if the laser comes on would be a jumper from Pins 1 to 3 for Interlock, and a jumper from Pins 13 to 2 for Discharge On. (The latter may not even be absolutely essential as the Discharge On input may float to a high level if unconnected.) And, of course, the Interlock Keyswitch on the power supply has to be enabled. After a 30 to 40 second delay, the laser should come alive pulsing to maximum current for about 1/2 second and then dropping to Idle current. If the tube is reasonably healthy, there should be a beam (and certainly during that 1/2 second), though it may be quite weak at idle. MAKE SURE YOU HAVE ADEQUATE COOLING if running for more than a few seconds. Even at idle, it's still dissipating the equivalent of a small space heater!
There isn't any problem using separate pots for current and light adjustments. The only caution is the maximum available current from the +15 VDC supply, 20 mA according to the Uniphase specs. The light adjustment sensitivity may depend on the particular laser head model (probably based on the -XX output power rating). Thus, adding a coarse adjustment in series with the top of the light adjust pot would be desirable. Same with the current adjust pot but to limit maximum current to a safe value for your particular laser. The sensitivity of the Power Monitor test point also depends on the particular laser head model and may not agree with either what is listed above (10 mW/V) or what is stated in the Uniphase specs (10 mW/300 mV). However, the sensitivities of 10 mW/V for both adjust and monitor do appear to be accurate for the 2214-30SLT and 2214-20GLT. I've also used the same control panel for a 2212-4SLBK without even having to adjust calibration.
I haven't figured out if I prefer the blue or green argon ion laser colors. The 488 nm wavelength is blue that really wants to be green; 514.5 nm is green that really wants to be blue. I wish there was a small air-cooled ion laser that did a nice yellow - the yellow HeNe at 594.1 nm is still my favorite laser color. What passes for yellow at 568 nm in a krypton ion laser doesn't really qualify - it's a yellow that wants to be green! :)
Ron Cole (gr8mxr@verizon.net) has put together a basic control panel including Enable, Idle/Run, and Current/Light switches, and separate pots for current and light level. Contact him for details and pricing. If you really don't know which end of the soldering to grab, this may be for you. :)
(From: Steve Roberts (osteven@akrobiz.com).)
If an interlock fails, the PSU must be completely powered down for 5 seconds or more or it wont restart. Some Uniphase PSUs apparently sense filament current and head plug configuration as an interlock as well as the two orange wires on the low voltage connector. Some may even sense if the filaments are warm. The timing is digital. The supply senses the power line for 5 seconds to confirm correct voltage. If that is correct, then the 40 second warmup delay provided you have good interlocks. Then it applies voltage to the tube and initiates startup.
The only connections that really matter for testing are the Interlock (pins 1 to 3) and Enable (pin 2 to +15 VDC). Make sure the keyswitch on the power supply is set to Run (1). With power applied, the red Power LED and green Interlock LED should be lit and the filament of the tube should heat up for 30 to 40 seconds before the starter is activated. The laser should come on shortly after this, initially at maximum current, then dropping back to the selected setting (Light, Current, or Idle) after a fraction of a second. If this doesn't take place as expected, check the following: