Hello all,
The above PSU fell into my hands after the owner replaced it with a new one (better brand).
The fan had failed and the PSU did not power on before i got it.
The fan rotor had a large crack and the axis was stuck in the bearing.
However when i got it the leds of the fan were lit while plugged. The leds were powered from a separate 5v supply on the PCB.
I recapped all the output caps using KZH series.
Got a new fan and the psu was ready to test.
I plugged it in a test system i have and everything was ok.
I even ran a combined stress test (Furmark for the NV 450GTS and Prime for the 4 core Phenom II of the system) for 5-6 hours.
I thought it was ok, as it passed the stress test. But 2-3 secs after i powered off the system, the PSU was trying to start again followed by some chirping sounds and the leds of the fan pulsing.
I removed the 24pin and 8pin and 6pinGPU cables from the motherboard and when i swithed the PSU switch on again it started the same thing ! Without any cables plugged in the motherboard.
I also had some light smell but no visible marks of something burnt.
After that i tried again and the PSU started normally again. Then after system shut down, the same thing again.
Only "visible" sign of some temperature increase is the cables of a thermistor on the heatsink of the output transistors.
Supervisor IC is Sitronix ST9S313A-DAG, if it is any clue to anyone.
The internals are shown in this review --> here.
I also uploaded some photos of the thermistor ( it had a metal holder bolted on the heatsink) and supervisor IC area
Any thoughts are welcome.
Thank you in advance !
The above PSU fell into my hands after the owner replaced it with a new one (better brand).
The fan had failed and the PSU did not power on before i got it.
The fan rotor had a large crack and the axis was stuck in the bearing.
However when i got it the leds of the fan were lit while plugged. The leds were powered from a separate 5v supply on the PCB.
I recapped all the output caps using KZH series.
Got a new fan and the psu was ready to test.
I plugged it in a test system i have and everything was ok.
I even ran a combined stress test (Furmark for the NV 450GTS and Prime for the 4 core Phenom II of the system) for 5-6 hours.
I thought it was ok, as it passed the stress test. But 2-3 secs after i powered off the system, the PSU was trying to start again followed by some chirping sounds and the leds of the fan pulsing.
I removed the 24pin and 8pin and 6pinGPU cables from the motherboard and when i swithed the PSU switch on again it started the same thing ! Without any cables plugged in the motherboard.
I also had some light smell but no visible marks of something burnt.
After that i tried again and the PSU started normally again. Then after system shut down, the same thing again.
Only "visible" sign of some temperature increase is the cables of a thermistor on the heatsink of the output transistors.
Supervisor IC is Sitronix ST9S313A-DAG, if it is any clue to anyone.
The internals are shown in this review --> here.
I also uploaded some photos of the thermistor ( it had a metal holder bolted on the heatsink) and supervisor IC area
Any thoughts are welcome.
Thank you in advance !
Attached Files