Quicksilver ticking from PSU when plugged in but switched off

#1 Sun, 4 Jan 2015 - 21:04 Quicksilver ticking from PSU when plugged in but switched off — #1

Hello

My powermac G4 Quicksilver has a patterned ticking noise that appears to emit from the power supply even when the machine is switched off.

Does anyone have any idea what might be causing this and what the resolution might be.

If you need a video I can quickly make one.

Thanks in advance.

PS The machine otherwise works as expected and ticking disappears when the machine is turned on.

#2 Sun, 4 Jan 2015 - 21:18 Quicksilver ticking from PSU when plugged in but switched off — #2

Whatever the pieces control the standby voltage is probably the issue.

Short of taking it apart or replacing might never really know.

#3 Sun, 4 Jan 2015 - 21:32 Quicksilver ticking from PSU when plugged in but switched off — #3

I posted a video of the issue. https://www.icloud.com/photostream/#A25Uzl7VCaEhI

I hope it helps you fine folks get a better idea of what is going on.

Thanks a bunch!

#4 Mon, 5 Jan 2015 - 02:43 Quicksilver ticking from PSU when plugged in but switched off — #4

Since it still runs, its possible the 5VSB doesnt have an adequate load anymore and its going into overshoot trip. a open smoothing capacitor on its secondaries would cause this. Also an open load resistor on the output section would cause this as well. probably dried broken solder joint creating an open.

Especially if its high hours, it could have a bad filter cap on the 5VSB.