Progressive Dynamics PD9280 Converter repair & mosfet ID

[albert001]

Hello,

I have a Progressive Dymanics Converter / Charger (PD9280) that was installed in a RV and all of sudden stopped putting out any DC as one it's 20 amp fast acting ceramic fuse keeps blowing.

One end of the 20 amp ceramic fuse has continuity to the AC black hot and one of the white wired of the rectifier. Possibly the rectifier is bad, however what's causing the fuse to blow can be somewhere after the rectifier and after the other end of the fuse , as anything connected to the circuit potentially can cause the fuse to blow.

I've been looking at the rectifier as these have been known to fail. The rectifier I'm able to find a part number and replacement.

https://www.digikey.com/product-detail/en/comchip-technology/KBPC2504-G/641-1851-ND/3300067

However there are two mosfets that potentially can go bad. Qa1 and Qa2. (neither have any continuity to the fuse) I have the schematics and other documentation from it's patent however I'm not able to find a part number for the two mosfets as it appears the part numbers have been distorted by a marking pen of some sort. (see pic)

https://patents.google.com/patent/US7782002

Link to schematic with mosfets Q1a and Q2b https://patentimages.storage.googleapis.com/US7782002B2/US07782002-20100824-D00004.png

I've only cleaned up two mosfets as it appears both will need to be cut out and I'm still trying to determine a part number before removing.

After cleaning  up the mosfets which appeared to have some corrosion, the 20 amp ceramic fused blew again.

here's a pic of the mosfets which have some corrosion. Both have plastic tubing installed near the bottom where the pins connect to the pcb. The mosfets I'm looking to replace are the two on the left.

[Chris56000]

Hi!

I've been reading that Patent Document, and, in my honest opinion, 2 X IRFP460 (Farnell, Digi–Key or Mouser!) should be found satisfactory to replace the original scratched–off devices – these are in an identical TO-247 package and have approximately the same Rds–on as the types suggested in the Patent!

I would NOT attempt to over–rate the devices as higher–power or higher current devices may have a substantially greater Qgs (gate–charge rating), which may require much more gate–drive current than the drive circuits can provide, leading to possible overheating and early failure of the replacement devices!

The Patent Document is very comprehensively written with excellent circuit descriptions and well worth a careful study!

Chris Williams