Ludlum model 3 issues

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Richard Hull
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Re: Ludlum model 3 issues

Post by Richard Hull » Fri May 08, 2020 3:53 am

I'm with Rex......."Thanks it works now", is not a fix! What fixed it!!!! We've gone through this posting for a bit now.... What fixed it??? We were left hanging by your response or lack thereof.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

Sarmad suseyn
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Re: Ludlum model 3 issues

Post by Sarmad suseyn » Fri May 08, 2020 9:02 pm

Hi Richard
I think my problem was the variable resistor
It is 64 watt resistor. And when i checked the ohms . It gives zero
I think this was the problem. Check it with a 100ohm resister
It burned my multimeter 1000v .
Cant change it right now because of curfew . Every electronics shop is closed. But im sure this is the problem
Thanks Richard

Rex Allers
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Re: Ludlum model 3 issues

Post by Rex Allers » Sat May 09, 2020 3:36 am

None of that explanation makes any sense to me. There's no 64W pot in a Ludlum 3. The batteries probably couldn't supply 64W if they were shorted. The little pot for HV adjust setting is probably 100K ohm. In the circuit it should draw microamps and micro watts.

Not sure how you were measuring resistance but 0 ohms (a short) seems very unlikely. I can't think of how a single 100 ohm resistor could be used in your diagnosis. I also can't imagine what in a Ludlum 3 could burn your meter.

Of the schematics I have found, the Model 3A looks probably closest to being similar to the pictures you have provided. Not the same but I would guess the circuits are very similar. I edited those schematics to make one page with the HV supply circuit and the HV adj pot as it would connect. I also added a purple dot in the same place where I put one in an earlier version of your picture that I posted. If you can't understand that circuit, you are probably not in a good position to diagnose your device.

Rex Allers

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