Question about click click sound in computer PSUs

Thread Starter

disturbed123

Joined Jun 11, 2020
75
i have heard this is some kind of protection. how to eliminate that noise put the supply all ok?

the question is more principal. i have here one cheap power supply and can use it for learning.

thanks
 

AlbertHall

Joined Jun 4, 2014
11,533
i have heard this is some kind of protection. how to eliminate that noise put the supply all ok?

the question is more principal. i have here one cheap power supply and can use it for learning.

thanks
Yes, that sounds like the protection circuit operating. It detects a fault and shuts down, then has another go at starting and that can generate a click sound at each attempt. They are usually difficult and always dangerous to repair, but pretty cheap to replace which would be my recommendation.
 

Reloadron

Joined Jan 15, 2015
6,137
On a 24 pin PSU main connector Pin #8 (grey) and on an older 20 pin PSU main connector Pin #8 (same as 24 pin) grey is the PWR_OK pins.

PWR_OK.png

On start up the PSU looks at its outputs, if all outputs are in tolerance the PWR_OK line transitions from a logic low to a logic high as seen in the above image. When a supply attempts start PS_ON pulled low the supply attempts a start. However if the PSU has an excessive load or other problem and PS_ON is held low you will hear, as mentioned, a clicking sound. The upper trace is the PSU PS_ON command. So if you want to see if Power Out is OK look at the PWR_OK line.

Ron
 
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