I am repairing a failed ATX computer power supply (PSU). It is rated 100-240V 9A input, 620W max output. Its 10 A bridge rectifier is dead, and I am able to get at most 8 A bridge rectifier as a replacement. 8 A is not 10 A, of course, but I live in Europe, we have got 230 V in mains, so my idea is simple: If the PSU is designed to work in a wide range of voltages from 100 V to 240 V without a manual switch, its 10 A circuitry is probably needed only for 100 V, but not for 230 V we use here in Europe. So I think I can safely put there 8 A rectifier bridge, or even go as low to 5 A or possibly even to 4 A without any problems. Is my idea correct?
I also replaced the blown 10 A glass fuse by a 4 A ceramic one, it should be just enough for the PSU and also can help to protect my 8 A replacement bridge from possible overcurrent.
My math: Originally 100 V, 10 A => 1000 VA. Now 230V, 4A fuse => 920 VA.
I tried it in praxis, it seems to be fine and working (under normal conditions, not fully loaded). So this is rather a theoretic question, I'd like to understand it.
If somebody is interested, it is Seasonic SS-620GB (S212II Bronze) ATX PSU.
Also, there is a fuse information on its printed board saying that 200-230V variants should be fitted with a 5A "H"-rated fast blow (T) fuse. I used the correct H T type.
Original bridge was GBU 1006: reverse current 5 microA, forward surge current 220 A.
The replacement is KBU 805: reverse current 10 microA, forward surge current 300 A.