I was recently given this non working charger.
It has been 25 years since I did my AD Electronics and about as long since I did anything with it, and for some reason my interest in electronics has been rekindled recently and I'm absorbing anything I can learn. Dave's Fundamental Fridays and repair videos are great sustenance.
The process so far...
Circuit seems to be rectifying on at the 240v level. Does this mean its a Switch mode?
Power on - No lights. Not charging
Open up
General look around - nothing immediately obvious
Check fuse - Open circuit
Replace fuse - fuse blew
Found all 4 rectifier diodes short circuit
Replaced all 4
Powered on - blew fuse and 2 of the diodes
Looked some more and found NTC blown and 0.47R on DC side blown to high resistance (edit - 0.43Ohm)
Here is the top and bottom of the board showing the above mentioned components.
![Repair of Ryobi BCL14181H Li-Ion charger 1058904-0](https://www.eevblog.com/forum/index.php?action=dlattach;topic=252602.0;attach=1058906;image)
![Repair of Ryobi BCL14181H Li-Ion charger 1058908-1](https://www.eevblog.com/forum/index.php?action=dlattach;topic=252602.0;attach=1058910;image)
I have tested pretty much all the diodes including zeners on the bottom. I can't read the chip numbers.
Is there anything else I should check or test and is there something else likely to have caused these devices to fail?
Can the NTC be substituted for something else as a temp fix?