Battery charger damage and repair

  An old Schumacher automobile battery charger has been used to charge the system auto batteries , for several years. One day, a couple of weeks ago, the charge went pffft. When I tried to plug the unit into the wall a grinding noise was heard. I took the thing apart. The construction was surprising. There are two button diodes used as rectifiers. One had shorted. I replaced both with standard through-hole tech diodes and reassembled the unit. Functional status restored.

Updated System Test run

 A lot of work needed to be done, but the testing was completed. 

The re-worked mosfet PCB functioned as a H-bridge reversible motor driver. But, during the testing, in the cramped space, I shorted out the PCB and blew out the Q4 mosfet. The PCB uses SMD technology which involves miniature components that lay flat on the board. Repair is therefore beyond my capability. Little experience and none of the specialized equipment. I'm trained in old school through-hole technology. Components are large enough to be inserted into holes on the board, then soldered. The new components have to be placed using tweezers.

 I'm waiting on a different design I ordered several days ago. The new PC will not require re-working, plus the new PCB uses through-hole technology, so repairs/upgrades, by me, will be possible.

One of the draw backs was the thin hook-up wire commonly used in prototyping designs. There are several wires running between the driver and other units. These broke three times. Frustrating is to say the least about the problem. I need to get some smaller gauge wire or consider using stranded wire.

The level shifting buffers worked and remain in place and ready. The limit switch software is tested and working.

I removed, tested, oiled, and re-placed the linear actuator.

Several short scripts were written and tested for use in testing the actuator.

The new driver PCB will arrive around the 12th. Waiting.