This is the internal power supply from my ICOM IC-775DSP (200 watts on transmit)
This isn't your normal 13.8v, 25a power supply. It is a 13.8v and 28v power supply (all in one).
It blew, toasting two MOS FETs, two resistors and the regulator IC. I replaced all of those, plus installed all new high grade caps. Checked the solder connections and repaired a few traces. All the diodes and bridge rectifiers tested good. Result: nothing out.
The power supply is very poorly
documented. It is not in the 775 Service Manual at all. I managed to find 8 pages of a copied copy of a copy of a copy of the power supply service manual (a challenging decipher).
My suspicion is the regulator IC (Mitsubishi M51977FP) is counterfeit and probably defective - I bought it from eBay/China. Only source I could find. Perhaps there a real source, or a "replacement" regulator IC.
In the meantime, I have put together two separate new power supplies (13.8, 30a and 28V, 11a) in the same size container as the original power supply. Just one problem with that. The original power supply has a "FAN" output connection that goes to internal circuits in the 775 (I think it is something other than just a 12v output, and I do have the schematic for that). Not sure how to resurrect that.
Does anyone know someone who might want to continue this challenging repair? I am running out of competence..
Thanks and 73