Laserscope 800 / ALE YD4 Arc Lamp Power Supply

[turbohead]

I have two ALE YD4 Arc Lamp Power Supply from a Laserscope 800 series laser. One of the power supplies works; the other does not.

I have a stand alone ND:YAG laser connected to a coolant pump and heat exchanger in series with a di-ionization filter.



To operate the ALE, I built the controller described here:

http://www.allen.dj/laserscope/

I have also been reading the YD4-6-8 Manual (Rev B.) which states in the troubleshooting section that if the arc lamp is not igniting, it is probably a failed spark gap.

To diagnose the fault in the power supply that does not work, I have been systematically swapping circuit boards between the working and non-working power supplies. So far, all of the boards appear to be functional which narrows my troubleshooting to the spark gap.

I have yet to find the spark gap (SG1) shown in the YD4-6-8 schematic.

Can someone help me identify the location of the spark gap? What does the spark gap look like?



Thank you!

[Laserman532]

if you know or speak to this fucking clown Pro Dj ALLEN - please tell him to remove my picture and name Immediately...

[turbohead]

In case anyone is interested, I found the spark gap referenced in the ALE power supply manual as SG1.

It is the innocuous glass diode looking component marked as Q1:





I swapped Q1 from the known working power supply and the arc lamp ignited!!

Now I just need to order an 800 volt spark gap. Probably not a RadioShack item.

[planters]

I like what you are doing. An arc lamp power supply is not a mysterious thing. It seems to me that a given lamp (and it could be say, the spec lamp for any of the Laser Scope models) will have a data sheet describing the trigger voltage and the running voltage x current. You could make or buy these generic power supplies. In addition, you could interface with these power supplies in ways the the medical manufacturer never did in it's 800 models. You might be able to modulate the current. See page 27.

http://www.excelitas.com/Downloads/Cermax_Eng_Guide.pdf

[dsli_jon]

Hey Turbo -

..I found the spark gap...It is the innocuous glass diode looking component marked as Q1
...I swapped Q1 from the known working power supply and the arc lamp ignited!!...

Sorry, but.. Respectully, I think that's just an 'innocuous glass diode', not the 'Spark Gap'.. Spark Gaps look either like a really-obvious glass-tube, w/ a 'spark-gap' (ie: the LAMP is, essentially, a 'spark gap', but one designed to-then sustain an arc..) Or, they look like this: http://www.alldatasheet.com/datashee...S/ST-0840.html ..Keep looking, you should find it.. I can't recall, off the top of my head, this-specific form-factor, but I can look later tonite / tomorrow, perhaps..

..Now, I'll admit - I haven't replaced one of those yet.. (haven't run-across a bad-one, believe it or not.. but.. pretty-sure that 'Q1' is just a diode, as-seen in the Schem. of the Power-Board #01-000-556, Page 33, there.. In fact, they Ref. (Page 24 (thier-Page 22) 'Q1' as just a 'diode to check', after the supply-input fuses have blown, etc, etc.. Point-being, just because Q1 was blown / you replaced it / the lamp lit, doesn't auto-prove that's an *800V spark gap* (good show, tho! .. I gotta go do my homework on the Power Board again, and I'll be happy to stand corrected, but pretty-sure that's just a diode..

...Now I just need to order an 800 volt spark gap.

Bzzt, wasn't the ST-0840.. It's the 'SCR', there.. ..Anyhoo, lemme do some more homework and get back to ya..

if you know or speak to ...ALLEN - please tell him to remove my picture and name Immediately...

..I WILL.. Seeing that pissed me off royally, when I first saw it.. I figured you already had served him with a 'cease and desist'... I'll call up ol' dj Duncecap, tomorrow..

j

[turbohead]

I thought it was a diode as well, except it does not have "diode type" markings. There is no black band to designate the anode and cathode. The one from the working board does not test like a diode. There is no conduction in either direction. Also, it is marked as "Q1" on the circuit board (one would expect a diode to be marked as "D1").

It is definitely the defective component. I literally "scorched the earth" and tested all of the parts on board (all were good). As a last resort, I swapped the "diode" from my working board and the arc lamp ignited!

Yes, if you could please let me know what this part is so that I can order the correct one, it would be very much appreciated. Right now I am just happy to find the fault.

[turbohead]

By the way, I have another faulty component for another ALE power supply. I need a replacement high power SCR. The original part number is "ACR44U12LE" or "BTW63 800RK."

The "ACR44U12LE" has a VDRM of 1600V / IT(AVG) of 44A. The "BTW63 800RK" has a VDRM of 800V / IT(AVG) 50A. If you have one "laying around," I'll be glad to make an offer plus shipping.

[turbohead]

I think that's just an 'innocuous glass diode', not the 'Spark Gap'..
j

I did some further research. I think the component may be a diac:

[turbohead]

I like what you are doing.

An affirmation from Sir Planters is very much appreciated. I'm not even in your league. Thank you for taking notice.

You might be able to modulate the current.

I have found the ALE Arc Lamp Power Supply to be very versatile. The 26 pin interface (J100) allows one to control the current manually with a 5k potentiometer.

[mixedgas]

I have a partial parts list. Its at home.
9 PM eastern before I can check.

Steve