Uniphase argon advanced help needed...

[dxs]

Hi!
I just received a nice argon set, psu 2214-40mla (the gold box), head 25mlup. It was working before it was shipped to me, and was probably really jolted during that ;-)
Actually, it does not work for me (I know... it's not "my laser is broken" forum)!
Symptoms are:
- psu correctly issues trigger signal command (5,5v across violet and green if I remember colors correctly), a bit low according to Sam's faq (??)
- I jumpered pins 1-3 and 2-13
- key is turned to on
- thermal interlock on the head is a short
- I checked all fuses in the psu, they're ok
- PS is set to 220v (I'm in France), I tried with a 110v transformer on the 110v setting, no change
- I can't get the psu to output DC+ (the hv 100v). I tried connecting only the round umbilical to the psu, and I checked for DC+ directly inside the PS: still nothing else than 0v.
- checked wiring from head to plugs, everything seems fine

Any hint?
Using the PS alone with no head at all, does someone know if jumpering the thermal interlock should get me DC+ out? Will it damage anything?
I can make measures if needed.

Many thanks for help.


Edit: Pictures will follow ;-)

[mixedgas]

cathode lit?

Steve

[Diachi]

cathode lit?

Steve

If you can't see the cathode lit down the bore, go inside the head and measure the resistance across the two pins at the back (cathode), it should be almost a dead short.

-Adam

[LesioQ]

Don't forget to wait about a minute. This much time is for cathde heating-up, only then the high voltage is applied to head followed by start pulse.
Do You have a factory remote for it or just a DIY panel ?
A picture might help with help
Piotr.K

[Laser Ben]

A picture would for sure help. How are you controlling the power supply? Did you get the factory control panel?

[dxs]

Stupid me, I forgot to say. Yes, cathode is lit, voltage across it is fine (around 2,5v). Resistance is a short when cold.
I wasn't sure if HV should be applied as soon as the PSU is powered, or after the delay when trigger command is sent. When the delay expires (around 25s on this ps), the 2 contiguous red and green LED on logic board light up, and I can measure the trigger signal command at the head. But no HV, and hence no starting. I tried waiting more, up to a minute, nothing else happens (there's even no magic rabbit going out of the ps ).
If of any interest, the red LED in the middle of the logic board is always lit.
I don't have the full blown commercial remote... euhhh... just 2 jumpers for now. I'll make the real thing the day I see coherent light out of this!

[dxs]

A thread if worthless without...

The head with start module visible:


How it looks with cover:


Inside PSU:


Logic board, you can see the red and green LED I was talking about on the left, and the red alone in the middle:


Head detail:


PS detail... don't shoot at the guy who made that, I'll buy a male plug asap:


According to Sam's Faq, using those 2 jumpers the system should be idling peacefully... Mine doesn't
While checking for HV, it's possible that a few times I saw a random voltage at the very moment when the trigger start command is issued, but so short my meter had no time to give a real value. I'm not brave enough to plug the HV output in my oscilloscope

[LesioQ]

Interlock in OK (1-3), so is the discharge command (2-13).
I'd suggest adding IDLE (11-4) and current control (11-5), as ot me it's not sure if You order the head to run light controlled with zero power request will it issue HT at all.

Oh, and measure voltage between 13 and 11 - do You see 15 Volts ?

Piotr.K

[mixedgas]

Sounds like you have no drive to the fet gates, or bad FETs/Reverse diodes.

NO drive could occur if you have no potentiometer or control voltage, so I'd add the wires LesioQ suggested.


Just for a sanity check, do you see a bore flash on a white card when the ignitor fires?

remember to keep you meter away from the ignite pulse.

Steve

[dxs]

I'll try that LesioQ and keep you informed. Right now I'm away for my job, I'll be back tomorrow.
Steve, I have no start pulse, because on this laser, the start pulse is made from DC+ (no boost voltage). No DC+ ---> no start pulse. HV pulse is made by the blue box you can see on the head (it's written "assembly..." on it).
13-11 was checked, 15v as it should. I also checked 2-11, about 12v, so it's floating high unconnected.
Thierry