Dremel Li-Ion Charger Stopped Working

[thaphatmaster]

This is my dremel charger for one of the Dremel / Bosch 10.8v (3s1p) Li-Ion packs. There are many like it, but this one is broken.

It stopped responding the other day. No light when a battery is inserted, no voltage at the output when tested.

The dremel itself and its battery are fine and working.

Looking online, many people just replace this type of charger with an Aliexpress version. However most of the through hole components look straightforward enough to replace if they are broken.

I'll do some basic poking about (continuity checks etc) later. I've already checked the internal glass fuse and plug fuse (both fine).

Nothing obviously looks burned or popped

In the meantime, here are some pictures of the circuit.

Any pointers for order of testing etc would be greatly appreciated.

[lotas]

Check these diodes for short circuits.

[thaphatmaster]

Whatcha know "top" one looks open both ways.

Is this a suitable replacement (IN5400)?

[lotas]

SBxxx is a Schottky diode, it has a lower junction drop than a regular one, raise one leg on it and measure it outside the board.

[stj]

you may want to brush all those metalic chips out of it - just sayin
drilling steel or aluminium over it?

[thaphatmaster]

I don't see those, but I'll give it a brush anyway.

It only really lives inside the fabric demel case.

If it's out of the case, its being used to charge the dremel, so it is unlikely I'm making metal chips.

[thaphatmaster]

SBxxx is a Schottky diode, it has a lower junction drop than a regular one, raise one leg on it and measure it outside the board.

Results are in (I also brushed it)

[lotas]

The diode is live.

[thaphatmaster]

Working?

I'll check the components here next as I've seen others with blown resistors / diodes in this area