Ps-305d power supply

[Abdulla544]

Hi
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?

[BreakingOhmsLaw]

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.

[aa0cn]

I did a finals repair on my PS-305D, so not the same issue, but you can find schematics for this unit here: https://aa0cn.neocities.org/ps-305dm.html
Or from PierAsia on his site here: https://www.pieraisa.it/php/myHwProjects.html
Hope this is helpful!