High Voltage supply for an Electrostatic speaker

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I have a few High voltage power supplies for an kingsound electrostatic speaker that don't seem to work properly. they were replaced by the previous owner and some of the units in the speakers are faulty as well.

The modules for the midrange panel vary between 5 and 6.5Kv and the tweeter between 2.6 and 3.4 KV.
The only difference is the number of caps in the voltage multiplier.

All of them had the DC input voltage 2K(P202) trimmer sealed with laquer. Most are reading too high so I replaced the trimmers on a few of them.
Only one of them reads correctly when I turn the new trimmer - a tweeter HVPS ranges from 2.4 to 3.4KV. The others vary by 0.1 to 0.4 KV and not always the same as the trimmer rotation.
Ideally I want to get around 4.5 to 5.5KV for the mid and 2 to 3.5KV for the tweeter HVPS.
I could tap off the multiplier array to get lower voltages but would like to get them going properly.

I have posted in the planar speaker thread but no luck.

The large grey capacitor like component confuses me. I would expect a 555 timer IC as in some of the circuits I googled.

I havent checked that the 7809 reg is actually working as yet but will do soon but thought it improbable that they would all fail.
The one that I have managed to get working had a few visible cold solder joints that I fixed so it's not improbable that they all need redoing.
I have just bought a board holder as I am tired of zapping myself while testing.

Hoping someone can give me a bit of information on these things in the meantime.
thanks,
kffern

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.
 
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at higher V board surface leakage can be a problem

I'd detergent and water wash, distilled water 1st rinse, then 91% isopropyl rinse, and dry before beginning to trust anything


knowing your meter/probe is high enough Z not to load the bias is good too
 
I used this type switching type power supply before .
And I found this PWM (Yellow box) is proprietary item. (no model and part no)


0z90Ev3.jpg
 
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