Milwaukee M12 Cordless drill repair

[Arkadius1984]

Hi all,

My name is Ark, and I live in the UK.

I'm troubleshooting (or actually struggle with ) my milwaukee m12 brushless drill - the component shown on the photo is a diode ( most likely schottky one, as voltage drop across it is only 0.34v) - however I can't find any information online as to it's specs - it has got marking as shown on the photo - I would really appreciate any help with identification. Also that diode is connected straight to the +12v supply as shown, but on it's cathode it only shows around 9.6v after battery is connected to the circuit - any ideas?

[frozenfrogz]

W37 might actually be W3Z for a W3 Zener diode.
http://www.s-manuals.com/pdf/datasheet/b/z/bzt52c2v0-bzt52c51_r37-2_diodes.pdf

Page 2 item 5 »BZT52C3V3«

Just a wild guess though

[Arkadius1984]

I was thinking the same - however that 0.35v drop doesn't fit:D unless there are zeners with lower than 0.6-0.7v drop:) even if it is zener, there is still a question of choosing the one with right specs:D

[frozenfrogz]

Would 9.6V be the correct for the circuit? Maybe it is a Zener that should regulate/stabilize at 3.3V but since it is damaged, forward voltage drop is no longer 0.7V and Uz changed to 9.6V - quite odd since I would expect a Zener to be either fried or working correctly...

[Arkadius1984]

I forgot to add that I've borrowed a similar drill from my mate, and comparing the voltages, the zener's cathode on his pcb is 11.6V in opposition to my 9.6v. It's really damn hard to troubleshoot electronics without a schematic - especially for someone like me who is a complete beginner