Another Bosch charger repair. This time 18V, 1.4A unit. This is quite a simple unit with through hole components.
Not one SMD in site.
Problematic part of the charger is its primary side.
Most common components to “release the white smoke” are:
In rare cases you can expect bad resistor R9 200k, 1% TH 1/4W, and if you forget to change 30Ω R7, you will burn the R19 (120Ω resistor).
Regarding the main FET, you can get away with anything close to N-Channel 800V, >2.5A, and <4.5Ω RDS(on).
It seems that F3NK80Z was used in older revisions, and MMF80R900P as an upgrade.
I’ve noticed one possible manufacturing issue. They tend to cover the PCB in some sort of epoxy to keep it safe from moisture. In the coating process, the epoxy seeps in between the V6 MOSFET and its heat sink. So when you replace the MOSFET it would be a good idea to clean the aluminium heat sink and, maybe, add some heat sink paste.
If you have a problematic transformer, you can compare it to the values below:
High resolution pictures of PCB:
Finaly, you can download a complete: AL1814CV part list in PDF
Very detailed level of component repair. Thank you from our service department here in Canada.
Glad I could be of service. Love your picture gallery.
Cheers