Today at Atelier Kaz - ex-Honda R&D, F1, Indy/CART engineer

The set of the Bose AMPs with the burnt damage on one of them.
The damage to other two AMPs were also quite severe.
None of them could be powered up.
On one of the board, I had to drill a hole and pass through the hard wire to re-establish the dissolved missing track.




After lots of scraping, soldering and using several hard wires to re-create the missing tracks, the two AMPs passed the initial bench testing and ready for the conformal coating, hot melting glue followed by thermal shock final testing.




The last board with burnt damage. After some measurement, it looked to be at least no damages to the Bose ICs under no power condition so decided to give it a go.

I didn’t like the poor soldering method used on the FETs so decided to replace all four. New ones installed.




Initial bench testing was promising so all three AMPs are now going through the final testing.

For the burnt AMP, bench tested it for more than 4Hrs with thermal shock stage after 1Hr into the testing.
For the rest of two AMPs, my standard process of 2Hr testing with thermal shock after 1Hr into the testing.




All 3 AMPs passed the final testing and ready to be returned to the owner.
Not sure how long the burnt AMP will survive but hope it will last for a long time.