Corsair RM850x (synchronous ATX) need help troubleshooting

[W1ngl3t]

Hi all,

I have a Corsair RM850x that refuses to turn on. I have 5v stby but as soon as I try to power it up it goes 'click' and does not deliver any voltages.
I have not been able to find any blown or shorted components and there are no bulging capacitors. I have replaced the APFC controller and for a brief period (2 or 3 on/off cycles) the PSU worked but then the fault returned. Perhaps heating the PFC area is what resulted in the temporary fix?
The only option I see now is to start pulling components one by one, but before I proceed, perhaps someone more knowledgeable could suggest a better approach.

Many thanks in advance!

[CapLeaker]

Check it out if it turns very briefly on and then turns off? If that’s the case the supervisor IC may be shutting it down. Post some straight shot high resolution pictures of the PSU, so we can see something.

[W1ngl3t]

So this morning I thought it would be a good idea to hit the PFC area with the hot air gun to see if I can get it to power on again... and *boom* something blew and the power went out in the whole house. I think it was the thermistor. Now the question is: was it the thermistor all along or did I create a new fault?
I've got my money on the thermistor being the culprit because I did not apply a lot of heat so it should not have blown up the way it did.

[CapLeaker]

Could it be a thermistor? Sure. But it just limits the power to the primary side and acts kinda like a fuse if it blows. So it shouldn’t blow up the PSU. I got no idea what you did. I think the supervisor IC cut the primary off.and you were going down the wrong road concentrating on the PFC without looking why it is not working. The supervisor can turn the PSU off. You would have had a look on the state of the Fault Protection Pin first. These are complicated little buggers,

[Robert Pryor]

Than you so much for the info.