Spectra Physics 261B tick ...tick ...tick...

[GooeyGus]

usually if it's ticking, everything in the PSU is alright (again, *USUALLY*). The starter circuit uses the same voltage as the tube to convert into a high voltage pulse, so usually ticking means the head is getting the high voltage DC and it's trying to fire.

Does the tube 'flash' at all while the ticking is happening?

I'm not sure about the smaller SP argons, but I know on JDSU argon lasers the current ramps all the way up for the starting of the PSU, so that seems normal to me, but I could be wrong. The reason I would guess that nothing is getting hot is because this current isn't going anywhere yet. It's probably just displaying what it's 'trying' to send to the tube rather than what is actually flowing across it. As soon as the PSU senses voltage across the tube the current instantly drops to idle or whatever it's set to.

Stick a white card directly in front of the output aperture while it's ticking and see if you get any flashes. No flashes while it's ticking either means the tube is up to air, is severely high pressure, or the start pulse is not getting to the tube for whatever reason (shorting to something else?)

If all else fails, pick yourself up a BD-10A hand-held oudin coil from ebay. These are worth their weight in gold. They output from 10-50kV @ ~1mA and are AWESOME for getting those hard-to-start tubes to fire up. It's one of the best laser tools I've ever purchased. One little zap to the tube should cause the argon inside to glow, letting you know there is still gas in there. Then while it's ticking give it another gentle zap and it should fire up. Avoid any seals on the tube and mirrors as the HV arc can poke holes

[keeperx]

like i said... its out of gas....

[mixedgas]

Keeperx, You dont know. You cant just say outta gas.

You need to measure the voltage across the tube during startup, preignite, keeping in mind that the ignite pulse will blow a DMM to bits.
Or test the PSU with a known good head. Or test the tube with a known good psu.
It is possible to have ignite pulses without enough current to run. It can be a open interlock due to a warn connector, there are a dozen or more things that can go wrong, and until its on a properly set up workbench, or ran through a swap test, its a guess.

On a 261, most of this is accessable inside the psu.

Steve

[argon-ion]

Aaaaaaagh !!!!!
Those extra pins in the remote socket are not there, they have not been fitted.
So that's that fix, down the swannie.

thanks
Argon Ion.

p.s. please see my posting relating to JDS uniphase PSU remote jumper settings.

[keeperx]

Steve, i was being facetious because I have no clue with this stuff.

"gas" is an obvious reference by way of bad pun to gasoline. thats why i said "out of gas" and gave no more detail. i was being funny. Well i was trying to be funny and apparently failing horribly.

[platinum]

Steve, i was being facetious because I have no clue with this stuff.

"gas" is an obvious reference by way of bad pun to gasoline. thats why i said "out of gas" and gave no more detail. i was being funny. Well i was trying to be funny and apparently failing horribly.

Sidestep FAIL.

[mixedgas]

[QUOTE=keeperx;92248]Steve, i was being facetious because I have no clue with this stuff.

Sorry, but low gas pressure is a valid fault on a argon. So is high gas pressure, and its not a real fun experience to try to find out if you have either fault or a psu fault. 200V at 10 amps plus a 10-20 Kv ignite pulse means you need a pretty good bench setup to even come close to working on these, not to mention about 25 different interlock configs between different manufacturers and users, often on the same 30+ pin connector, but with different pinouts and levels.. I have a couple of BD10s and a set of PSUs and speciallized ignitors that will light almost anything ION on the planet and even I have to do comparison tests and swap tests, and I WROTE the majority of the FAQ on these. Not to mention about 10 years of doing social engineering to get the schematics, data and test sheets, and you could say publishing some of them has been detrimental to my career, as in yes MR Roberts, we'd love to hire you here at Sfutter Lasers, but there is a matter of needing you to erase or reword certain things you've published in the FAQ.

That is why the slight anger over your comment.

Steve

[keeperx]

well i thought it was funny...

like if someone were to ask "i have a pair of high power magnetrons with differential anamorphic sequence shifters and i cant get them to work" I would probably say "Have you tried plugging them in?"...

[buffo]

Well Alec, if you can't offer someone any advice on "high power magnetrons with differential anamorphic sequence shifters", then it's probably better to not say anything, rather than trying to sound funny and failing - right?

Argon-Ion;

Ok - your PSU doesn't have the extra pins. So there must be some other reason why the interlock light on the PSU isn't coming on. Unfortunately, I don't have a clue what that could be! Sorry. (My guess is that this is an indication of a problem with the PSU.)

Also, with regard to what Gooey Gus wrote - while the JDS uniphase units might ramp the current all the way up to start, the SP 261's do not. You can start them at idle if you want (which is around 4 amps), or you can start them at any other current all the way up to wide open (which is around 12-14 amps, depending on how robust the PSU is.)

If you had the unit in current mode and had the current adjust dialed down to the middle of the range, then there's *no* reason for the meter to read 12 amps. Also, that current meter reads off a sensing resistor that is in-line with the high voltage output of the PSU. So if you've got a reading, then 12 amps at around 90 to 110 volts DC is going somewhere! And if it's traveling down the tube, then there should be a plasma glow that you can see. (Use the white card trick that Gus suggested and see if you see a faint purplish halo of light...) Maybe you've got a problem with the current regulator and it's dumping max current down the tube regardless of the setting. I actually had this happen on one unit, but the tube would still pulse and flash...

As for the splashes of paint - well, I'll leave that for you to experiment with. But hey - if teenagers can make their cars go faster by adding stickers, maybe some day-glo orange paint will fix your PSU. Then again, maybe not...

Seriously though, If that current meter is accurate, then I think you've got a discharge traveling down the bore. If that's the case, then you should be able to see this. Then we just need to figure out why it's not lasing. But if you in fact do *not* have any current traveling down the tube, then you've got something seriously hosed in that PSU, and I'm afraid I won't be able to offer much help in fixing it. (Though Steve's suggestion to check Sam's Laser FAQ is a good one. There's tons of great information in there, most of it written by Steve!)

Adam

[GooeyGus]

I just thought of something else... If the tube is lit down a gas return in the tube you wont really see much of a plasma glow, it will also cause your current to read all crazy, AND the starter pulse will keep going because it wouldn't be seeing the correct voltage drop.

I had this happen to a smaller tube I have here.

has this tube worked in the past or is this your first time trying to start it?