Author Topic: Ps-305d power supply  (Read 226 times)

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Offline Abdulla544

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  • Country: iq
Ps-305d power supply
« on: May 26, 2021, 09:45:11 am »
My ps-305d 30v 5A power supply '' FINE'' range didn't work properly so I opened it up and I just figured out that it was a 1k dual-line pot that u can adjust the voltage at about 0 to 2.5v the button of it didn't work I didn't have 1k dual-line pot instead I attach 50k then my power supply showed short-circuit on the output display nothing wrong happened like smoke or something but I no longer have the ability to control the voltage I just can control the amp section and by the way, the output polarity protection diode didn't short and I also tested the output ohmage it showed 850ohm not short-circuited.
Can u please help me how to fix it?

Offline BreakingOhmsLaw

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  • Posts: 190
  • Country: de
  • Certified solder fume addict
Re: Ps-305d power supply
« Reply #1 on: May 26, 2021, 10:17:27 am »
You already answered your own question.
The fine adjustment is a potentiometer that is in series with the coarse adjustment. You replaced that with a 50k instead of 1k, so that can't work.

Replace the 50k pot with two fixed 470 Ohm resistors from wiper contact to upper/lower pin and see if the coarse adjustment works again.


Offline aa0cn

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  • Posts: 2
  • Country: us
Re: Ps-305d power supply
« Reply #2 on: June 22, 2021, 07:14:25 pm »
I did a finals repair on my PS-305D, so not the same issue, but you can find schematics for this unit here:
Or from PierAsia on his site here:
Hope this is helpful!
« Last Edit: June 22, 2021, 08:51:56 pm by aa0cn »

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