Electronics > Repair

Repair of Ryobi BCL14181H Li-Ion charger

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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.

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?

if the fuse has blown  check the transistor on the dissipator plate,  could / should be an mosfet,  remove it and check for shorts between the pins

You're on the money. Shortly after posting, I traced the resistor to the Source of the ndf04n60zh on the heatsink. The D and S were shorted. The tranny seems to test OK across each coil and all the local diodes and capacitors test good to. Anything else I should look for?

This MOSFET seems to be unavailable in Australia. 3 months via Aliexpress, so hoping for a local substitute.

Do I see a crack on that IC?

I did notice that but put it down to just a physical nick, but you could be right. I've taken the best photo I can with my rubbish OPPO phone using Open Camera, highest res, macro focus, zoomed, and cropped to keep the file size down. I don't have a decent magnifying glass to read the part number properly. Maybe someone recognises the number from what's visible?


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