HeNe PS woes..[solved] photo update:JDSU 1135P dissection/decanned

hwang21 · Jun 22, 2015

Whoa that's a deep shade of purple... sad laser

Most of my HeNe's that I bared tubed used a 5W 75K ballast and like a 3W 10K stabilizer at the other end. Not really necessary though. The fact that you see flickering should mean it's good

vk2fro · Jun 23, 2015

Like everyone has said, if you get the characteristic orange flashes in the tube (without the ballast resistor inline) the tube should work once you get one in the anode lead.

Try firing it again with a white card in front of the OC and you should see flashes of laser light each time the tube flickers. This test will tell you if the mirrors haven't suffered significant shock; not enough to cause the tube to come up to air, but enough to whack them out of alignment (I had an NEC tube with this problem. Running the tube with a plastic tube over the HR and rocking it, would get it to produce an emission. So I tried to give it a bit more pressure in the direction it needed to produce a beam and it cracked the seal, bringing it up to air

)

ultimatekaiser · Jun 24, 2015

True, but running it without the anode is bad for the tube, do it'd be best to just wait till you run it properly.

vk2fro · Jun 24, 2015

Very true - not worth ruining the tube for the sake of some time and a 20c resistor.

Down with Umbrella · Jun 24, 2015

Looks like for now this project is benched till later in the week. I got a notice today that the 2x resistors I ordered were shipped. This frit stuff seems pretty tough but brittle. The mirrors could be shot, I hope is hasn't suffered the same fate as sigurthrs.

Down with Umbrella · Jun 26, 2015

New developments:
The resistor came in last night. After work before even eating I ran out side to the garage and soldered it in as close to the tube as possible, I also used a cotton swap and some Eyeglass cleaner to clean the mirrors. Flipped the power supply on and BAM! Photons! No flicker, great output. Seems awesome. I was ecstatic this dead tube had been brought back to life!
Now the down side. I let it run for 15mins with no issues. I turned it off....a short while later I went back out to try it again and all it did was flicker like it was doing the first day

hmm.
Than I noticed my wiring from the Alden connection to the leads leading to the anode and cathode were arcing at the crimps.(less than ideal but it was ok for testing I suppose)

-I spread the +\- further apart soldered them and taped them. That mitigated the sparking but not the flicker.
- I soldered the 75k ohm ballast CLOSER to the anode <1"
- increase wire size to 18guage? Shouldn't matter too much but worth a try.
-by passing the 10k ohm on the other side.

All resulted in a flicker.
I might try changing the 75k ohm 5 Watt resistor. Could have failed.

Thought?
Is this cycling on/off and testing going to damage my lab PS? I do not want to toast that. Also what would happen if it was wiring backwards?

Thanks guys. I was so sure it was fixed I didn't even get a photo

Sigurthr · Jun 26, 2015

Down with Umbrella said:
New developments:
The resistor came in last night. After work before even eating I ran out side to the garage and soldered it in as close to the tube as possible, I also used a cotton swap and some Eyeglass cleaner to clean the mirrors. Flipped the power supply on and BAM! Photons! No flicker, great output. Seems awesome. I was ecstatic this dead tube had been brought back to life!
Now the down side. I let it run for 15mins with no issues. I turned it off....a short while later I went back out to try it again and all it did was flicker like it was doing the first day hmm.
Than I noticed my wiring from the Alden connection to the leads leading to the anode and cathode were arcing at the crimps.(less than ideal but it was ok for testing I suppose)

-I spread the +\- further apart soldered them and taped them. That mitigated the sparking but not the flicker.
- I soldered the 75k ohm ballast CLOSER to the anode <1"
- increase wire size to 18guage? Shouldn't matter too much but worth a try.
-by passing the 10k ohm on the other side.

All resulted in a flicker.
I might try changing the 75k ohm 5 Watt resistor. Could have failed.

Thought?
Is this cycling on/off and testing going to damage my lab PS? I do not want to toast that. Also what would happen if it was wiring backwards?

Thanks guys. I was so sure it was fixed I didn't even get a photo

Hot tubes require a very high voltage to start. Let it get cold and see if it starts up, if so that's normal for an older tube.

Can side is cathode. Reversed can kill a tube over time but almost always fires up even easier, paradoxically.

Down with Umbrella · Jun 26, 2015

The tube is wired correctly. Man, not many options. The voltex maxes out at 3200VDC.

ultimatekaiser · Jun 26, 2015

Nah. Just let it cool down like suggested. The voltex works it's just a bit marginal for that tube. Old HeNes require a bit more voltage to run, and as the y warm up they require more voltage to start. I have a ver long 26" tube that gas similar woes ever since I bare tubes it. Starts easy cold, but when warm it flickers a second before it 'catches'. It's normal.

Sigurthr · Jun 26, 2015

UK you know the voltex, what topology is the HV line? If it is inverter via chopper is there a Vreg on the DC line? If so it could be modified to allow a higher voltage, or if unregulated like CO2 supplies you could just have DWU run it on a variac. It's a CC supply when voltage is at maximum, so should work.

Down with Umbrella · Jun 27, 2015

Sigurthr said:
UK you know the voltex, what topology is the HV line? If it is inverter via chopper is there a Vreg on the DC line? If so it could be modified to allow a higher voltage, or if unregulated like CO2 supplies you could just have DWU run it on a variac. It's a CC supply when voltage is at maximum, so should work.

I do have a Variac I've been itching to use on something other than a pump motor but I assumed the input AC on the Lab supply had some type of over volt protection.
I have not opened the supply yet to see if a modification is possible.

icecruncher · Jun 27, 2015

Down with Umbrella said:
- increase wire size to 18guage? Shouldn't matter too much but worth a try.
-by passing the 10k ohm on the other side.

All resulted in a flicker.
I might try changing the 75k ohm 5 Watt resistor. Could have failed.

Something worried me

Question: What wire is 18gauge?

Is it the high voltage wire, or the leads into the PS.

Just a thought but most HeNe lead wires are special silicone coated and designed for helium neon tubes. You can run into probelms if you try and run regular wire for the cable from the HeNe supply to the tube.

Shorting on the leads could also damage the PS.

Down with Umbrella · Jun 27, 2015

You are correct, I don't have HV leads. When I spit apart the Alden wire it had one wire with heavy silicon and the other was uninsulated. From there I used some wiring at the house. I believe it's just a standard 18gauge Home Depot special.

There WAS some arcing when I crimped the leads too close to each other. But I separated that quickly and taped it well.
I do have one 12" piece of 14g GTO left over from my tesla build.

Sigurthr · Jun 27, 2015

Down with Umbrella said:
I do have a Variac I've been itching to use on something other than a pump motor but I assumed the input AC on the Lab supply had some type of over volt protection.
I have not opened the supply yet to see if a modification is possible.

Yeah don't try it. That's why I asked UltimateKaiser, as he has experience with the voltex psu. The variac trick only works on very specific supples (like chinese CO2 ones), so it is risky if you don't know beforehand.

Down with Umbrella · Jun 27, 2015

Power supply. The one part I was concerned about damaging is now doing strange things then cut out on me. I put an end to the decanned tube project this morning.

After all this I put the ps back on my green heNe which I knew it worked perfect with and as soon as I hooked it up it started making a high pitch screeching sound. I turned it off than on again. The sound tapered off than the output of the hene ceased.
Edit: when flipped on again it will power up with the screech.

I don't see any fried parts when I take the cover off but something is definitely wrong.

icecruncher · Jun 27, 2015

Down with Umbrella said:
Power supply. The one part I was concerned about damaging is now doing strange things then cut out on me. I put an end to the decanned tube project this morning.

After all this I put the ps back on my green heNe which I knew it worked perfect with and as soon as I hooked it up it started making a high pitch screeching sound. I turned it off than on again. The sound tapered off than the output of the hene ceased.
Edit: when flipped on again it will power up with the screech.

I don't see any fried parts when I take the cover off but something is definitely wrong.

My guess is that the tube is fine, but the power supply shorted and ended up not being very happy..

The arcing probably caused some issue. What? I don't know.

With it arcing, it may have stayed in the initial start voltage for a long time or shorted, thats my best guess.

HeNe PS woes..[solved] photo update:JDSU 1135P dissection/decanned

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