I have a HP/Compaq DC5000 SFF pc, that uses a proprietary PSU that runs HOT!! It runs so hot that I have had to recap it twice. It even managed to bloat some Panasonic FC capacitors after about 4 years of 24/7 use. I tried connecting the fan directly to 12v, but found that it was very noisy and not very effective. I have also removed the brown glue that goes conductive over time.
Anyway, I was wondering if it would be possible to increase the efficiency of the supply, and reduce the heat output, by replacing the primary side mosfet, which is a single Fairchild 9N90C 900v 9A part with a RDS of 1.4 ohms with a part with a much lower RDS. I was thinking something along the lines of a Fairchild FCPF22N60N, which has a RDS of 0.165 ohms and a better (22A) current rating. However, the voltage rating is lower, only 600v, and I was wondering if that would cause a problem.
I was also thinking of replacing the secondary side rectifiers with parts with a lower forward voltage drop. I assume as long as the voltage and current ratings are the same or better, that I should have no problem there.
Fairchild 9N90C Datasheet http://pdf1.alldatasheet.com/datashe...A9N90C_06.html
Fairchild FCPF22N60N Datasheet http://www.fairchildsemi.com/ds/FC/FCPF22N60NT.pdf
Anyway, I was wondering if it would be possible to increase the efficiency of the supply, and reduce the heat output, by replacing the primary side mosfet, which is a single Fairchild 9N90C 900v 9A part with a RDS of 1.4 ohms with a part with a much lower RDS. I was thinking something along the lines of a Fairchild FCPF22N60N, which has a RDS of 0.165 ohms and a better (22A) current rating. However, the voltage rating is lower, only 600v, and I was wondering if that would cause a problem.
I was also thinking of replacing the secondary side rectifiers with parts with a lower forward voltage drop. I assume as long as the voltage and current ratings are the same or better, that I should have no problem there.
Fairchild 9N90C Datasheet http://pdf1.alldatasheet.com/datashe...A9N90C_06.html
Fairchild FCPF22N60N Datasheet http://www.fairchildsemi.com/ds/FC/FCPF22N60NT.pdf
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