Rescued this one
Started it up in the computer case, and noticed that it would shut down after about 10s in the BIOS
Took it out, connected to hard drive and it loses all power on all rails (except for 5VSB) after about 40s or so. (the same result happens without a hard drive connected)
The 5VSB drops to 2.5V when it 'shuts down'
And the voltage across the primary cap falls from 335V to 330V at the same moment
I think that the 5VSB is regulated by an A6069H PWM chip (which was initially dropping to 2.5V even before the the PS-ON was grounded - but it now stays at 5V if the PSU isn't started)
It has a CM6800 APFC chip.
I thought about bypassing it, to see if it was the culprit, but it looks too complicated to do after looking at the application circuit that's pictured in the PDF.
Monitoring Vcc on the A6069H PWM standby(?) chip:
11V when PSU is first switched on,
then jumps to 18.6V when PS-ON is grounded,
then falls to 9.63V when PSU shuts down after about 40s
Any experience/thoughts as to what might be causing this phenomena?
Started it up in the computer case, and noticed that it would shut down after about 10s in the BIOS
Took it out, connected to hard drive and it loses all power on all rails (except for 5VSB) after about 40s or so. (the same result happens without a hard drive connected)
The 5VSB drops to 2.5V when it 'shuts down'
And the voltage across the primary cap falls from 335V to 330V at the same moment
I think that the 5VSB is regulated by an A6069H PWM chip (which was initially dropping to 2.5V even before the the PS-ON was grounded - but it now stays at 5V if the PSU isn't started)
It has a CM6800 APFC chip.
I thought about bypassing it, to see if it was the culprit, but it looks too complicated to do after looking at the application circuit that's pictured in the PDF.
Monitoring Vcc on the A6069H PWM standby(?) chip:
11V when PSU is first switched on,
then jumps to 18.6V when PS-ON is grounded,
then falls to 9.63V when PSU shuts down after about 40s
Any experience/thoughts as to what might be causing this phenomena?
Comment