Battery Charger

[TZRACE]

So, I am new to this forum. I am not an electronics whiz. But, being in the HVAC trade for many years, I have limited electronics experience. Anyways, I have this Makita battery charger that quit working and upon closer inspection, there is an obvious diode or something that has shorted out on the board. Problem is, it's burnt so bad, I can't identify it. I tried researching the board Mfgr. for a schematic or diagram, to no avail. I think that if I were to replace it (I am able), I could probably make it operational. Thanks for any help!

 

[JimB]

there is an obvious diode or something

I think that you will find that this is an "or something".
Actually it looks like a transient suppressor.
If you look at the track side of the circuit board, I think that you will see that it is connected directly across the incoming mains supply.

You could try removing the burned suppressor, the battery charger should work OK without it.
If the charger does work OK with the suppressor removed, then we can consider what would be a suitable replacement.

Your suppressor has obviously stopped one transient too many, it has done its job.

JimB

 

[tvtech]

There will be a blown fuse too that you will need to replace when the MOV destroyed itself.

 

[TZRACE]

Wow! Thank you. I will remove the suppressor and check the fuse. Thanks for your help, I'll let you know what happens and go from there.

 

[TZRACE]

Jim,
So, I had done a little more research after chatting with you and yes, do believe it is a transient voltage suppressor diode. It indeed does tie in at the line and neutral mains supply on the other side of the board. Removed the suppressor and checked the fuse, it was blown. Replaced with a temporary fuse, test and charger works fine. I will order a new correct fuse but, was able to find a suppressor with it being so badly burnt, no identifying marks. I found one that is almost identical physically but, a different color. From the other info I browsed, Not sure if it's critical. I know it should have the correct values but, once again my search from the board manufacturer was unsuccessful.
Thanks again!