JDSU 1218-1 Powersupply+1145p.. Will it damage my other HeNe's?

Just a question... see if anyone knows:

I have a JDSU 1145P HeNe tube... I have a 1135P and 1674P coming. I know the 1218-1 PSU (3700v, 6.5ma) was designed strictly for the 1145P...

I heard that HeNe tubes were pretty resiliant (but there's the ballast to think about). I know the 1135P is 3100v@6.5ma, and the 1674P is 2700v@5.0ma.

Would it be possible to just -test- the 1135P and 1674P heads on the 1218-1 PSU without damaging them?

Otherwise, I guess I'm going to have to look for a JDSU 1216-1 and 1208-1.


(Reader's Digest version: 3700v JDSU HeNe power supply. Will it hose 3100v and 2700v rated tubes?)

Really what I want to do right now is just test the heads and make sure they work; not run them for extended periods of time.

They will be fine

Peace,
dave

HeNe power supplies have a compliance range, below that there is too much voltage over the power supply instead of the tube. It would dissipate more power, that's for sure. My guess would be a tube with 1000v lower voltage would be too low.
But I'm unfamiliar with these power supplies, so I can't say how far they will go without problems, only guess.

Hmm. The 1218 - It'll light my 1145P, both of my 1135Ps, just fine.. But my 1674P -- no go. I just got the 1674P and the seller promised it was tested/working..

I am getting a 'proper' power supply (and a 1676P) from Sam Goldwasser tomorrow...
..but would "too much power supply" cause the tube not to light?

Or, are the chances that the guy sent me a bum head?

Or could the power supply have killed the head that fast?

HeNe laser tubes are quite robust (electrically I mean), only running them in reverse for more than a few minutes or running at a too high currect too long can damage them as far as I know. Depending on current this is from a few tens of minutes to hours. Power supplies die way sooner.

A 1674P, is that a polarized green tube? It should work just as easy as the 1135P I think. Does the tube try to start or nothing at all?

Yeah, it's a polarized green.. Was hoping to get a green, and this was an ebay guy who said it was tested. (Was packed pretty decently too.)

No try, nothing. Not a flash, and no glow inside the window. Nothing at all.

There's also a 'click' that happens in the PS when the other tubes start -- this one, nothing. I wait about 15-20 seconds; the others start within 5.

I don't think the tube is cracked or broken inside.

hmm. strange.

Looking into the aperture (with goggles, but only 0.75mw anyways) -- it is flickering. There's a pulsing dim red light... Could that mean anything?

Sounds like the current output of the PS isn't high enough.

See, that's odd, because the 1674P requires 5.0ma @ 2100v, whereas the power supply (1218-1, for my 1145P) is rated at 6.5ma @ 4100v. Yes, Too much. But shouldn't kill the tube... and from what i'm understanding: should light it.

Waiting for a 5.0mA 2100v power supply on UPS today but, I'm betting on it having a cracked bore

If it lights, it's not cracked. If it doesn't stay on, it can be a gas problem, a power supply problem, or even something else. You have a tube requiring 2000v less than the power supply gives, it may just shut off because it senses a short. Give it a shot with the other power supply. But even on a start pulse some green would come out. Microwatts, but easily visible.

See, I just got the corret PS from Sam.

The tube I got from him (1675P) works *great*.

This 1674P, though -- with this supply, (exact same ratings and reqs as the 1675P) -- nothing but a dull violet glow from behind the mirror. No green.

Solid dull violet glow. Tube stays lit. (I've had it lit for about 5 minutes now with the new PS.) -- Not the faintest trace of green light. (Doing this in a darkened room.) Not even a microwatt.

Strange...

The discharge spectrum is not visible because of the mirror reflecting a certain range of wavelengths. It's a typical black tube head, right? Maybe you can get one of the caps off to see the discharge of the tube. That way, you can view the spectrum and check if it is an gass fill problem. If it is, the seller sold knowingly a dead tube, gas fill only changes with years. Green HeNe's are even more critical on the gas fill. The discharge spectrum for a green HeNe is probably slightly different than for a red HeNe, but a very purple discharge is bad in any case. The mirrors are made for green, so they pass red and blue, that makes purple, so don't be worried about what you view through the mirrors, it's not representative.

More probable would be that the shipping was bumpy and that the mirrors are out of alignment. Here also you can remove the front and end caps and gently (!) push with something isolating against the mirror mounts.

In both cases: there's a fragile tube in the head, be very carefull! And there's HIGH voltage in there, probably on the mirror mounts itself. Only bring tools that are properly shielded close to the head, and remember that it can keep it's charge after it's powered off.

It's a typical black tube head yes. Compared to my 1675P, the discharge is dim, and sometimes 'sputters'.

So I do believe you're right about the gas fill problem. The mirror mounts I don't believe can be changed or adjusted; this appears to be a one piece deal.

(So basically, it's worthless, right?)

The seller was an ebay seller; guaranteed it against being DOA with 30 day return policy, but now is not responding any further. (Have sent 4 messages in 4 days, with no response.)

aryntha said:

See, I just got the corret PS from Sam.

The tube I got from him (1675P) works *great*.

This 1674P, though -- with this supply, (exact same ratings and reqs as the 1675P) -- nothing but a dull violet glow from behind the mirror. No green.

Solid dull violet glow. Tube stays lit. (I've had it lit for about 5 minutes now with the new PS.) -- Not the faintest trace of green light. (Doing this in a darkened room.) Not even a microwatt.

Strange...

Click to expand...

Well I think a return is your best bet. Start a dispute if they fail to answer.

Some options depending on what you want to do.
Listen for ticking/arcing maybe its shorted internally. If it fires letting it run (days) sometimes can help. If that falls or you feel adventurous then I would take the tube out and replace the ballast resistor. It also ensures you have no shorts on the heat tape?. (Not sure whats it is called but present in some.) That also lets you see what color the bore is. How to remove it is on Sam's sight and you will want to keep it intact or have a replacement. Longer tubes like to keep the heat consistent the length of the tube or you lose power. Other color HeNe's even more so as they are even more inefficient power in versus mW out..

I would "think" mirror misalignment of a HeNe in its tube is unlikely to change during shipping enough to stop lasing but that is a good candidate for your problem. Also aligning them is difficult and a very slow process. At least for me so if you decide to try that find out what your options are by taking a picture of each end of the tube and post. They have different setups and know which one will get yo better advice.

Remember the tube is high voltage and both power supply and tube will hold a charge after turned off as mentioned.

Sam is the man to ask but check his site first for more info.
http://repairfaq.ece.drexel.edu/sam/laserhen.htm

Best of luck on what ever course you choose.