Re: Repairing Fortron Epsilon 600W

I replaced all caps, but the problem is still here - big spikes on all rails, with load and without. What is the usual voltage on the main filter cap? Currently is 400V.

Re: Repairing Fortron Epsilon 600W

Hi,
Thank you for the reply. The attached schematic is very similar to my PSU.
The replaced cap was C15, which in my case was 100uF/25V.
I found that for all caps, even they have the rated capacitance, their ESR is probably terrible due age. Just adding 100uF/400V to main filter cap, reduced the spikes more than twice. I ordered replacement for all caps....

Hi,
I want to restore one old PSU. I found the main reason to not working. It was small cap (100uF/25V) on the Vdc bus going to the PWM controller. I replaced the cap with 470uF/25V (don't have currently 100uF) and PSU now works, tested under load with old GPU (ATi HD5830) and Furmark software. The replaced cap doesn't have any external signs of malfunction, even with capacitance meter is value is OK. But with it Vdc bus is ~11V and adding a small value like 4.7uF put the bus right, where it should be ~15.5V.
What currently doesn't like is the spikes on 12V and 5V buses. Please see...

Re: New Members - please post your introductions here

Hi Everybody!
I'm software/hardware specialist, currently trying to bring one old PSU back to life.