Wanptek Power Supply KPS305D - Out not stable

[abuhafss]

Hi

My bench power supply has started giving unstable output. The voltage fluctuates continuously even when the POT is idle. The PCB inside shows no damaged or burnt component. No domed capacitors.

Any idea, what's wrong with it?

 

[davenn]

My bench power supply has started giving unstable output. The voltage fluctuates continuously even when the POT is idle.

is this with or without load ?

 

[abuhafss]

is this with or without load ?

Without any load.

 

[abuhafss]

One more point, when the voltage POT is turned slowly to maximum, before reaching the limit a slight mechanical click heard and the voltage slowly goes down to 0. Then, if the POT is turned slightly towards the minimum side the click sound is heard again and the voltage changes abruptly.

 

[Martaine2005]

This sounds like dirty pot contacts.
But, is the click you hear a relay?. Some of these bench supplies have relays for different voltages.
Could still be as easy as cleaning the pot or pots with contact cleaner.
I would do this first to rule it/them out.

Martin

 

[abuhafss]

This sounds like dirty pot contacts.
But, is the click you hear a relay?. Some of these bench supplies have relays for different voltages.
Could still be as easy as cleaning the pot or pots with contact cleaner.
I would do this first to rule it/them out.

Martin

Thanks for the tip, it worked.