Makita Charger Not Working

R!f@@

Joined Apr 2, 2009
10,004
By the way,
If it blew, then there should be a reason. Low value R just don't blow for fun. It's a protection resistor of sort. I believe,. The shunt R is the big one.

If the 0.47R is supply power to the PWM chip, then you have main issue. A blown PWM or, and the MOSFET


edit : correction.
The PSU chip starting with "MIP" could be the issue.
 

Thread Starter

VLCT

Joined Jun 15, 2024
29
If it blew, then there should be a reason. Low value R just don't blow for fun. It's a protection resistor of sort. I believe.
So if I replace the resistor is there going to be a high chance that something else is causing this and it will fail again??
Anyone else think that replacing the resistor wont be the fix for this??

Should I start a new topic this??
 

Dodgydave

Joined Jun 22, 2012
11,395
The resistor has blown probably because the Mosfet has blown, trace where the resistor is connected to , post pictures of the circuit board both sides.
 

Thread Starter

VLCT

Joined Jun 15, 2024
29
Charger 1.jpg1.jpg2.jpg3.jpg
4.jpg




One side is working so I can use that for reference with testing components.

The mosfet is 0.532 and OL.
 
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Dodgydave

Joined Jun 22, 2012
11,395
The resistor is in series with the small transformer supply (T101) I would check out the diodes around that area , especially on the output side and any other items.

IMG_20240624_152802.jpg
 

R!f@@

Joined Apr 2, 2009
10,004
Here you can see the 0.47R supply Raw DC ( ~ 300VDC ) to the stby PSU chip.
You need to change the MIP chip and the 0.47R.
The resistor can be changed to any value ranging from 0.1R to 0.68R. Keep the wattage or size same.The R serves as a protection fuse function

If there are no shorted diodes, the PSU will work once you replace them both.

Based on my experience I am saying this. The PSU chip might blow if the main filter cap has degraded. Need to check the capacitance of the main filter cap
 

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Thread Starter

VLCT

Joined Jun 15, 2024
29
Thanks R!f@@, a bit to get through there, so will do my best,:)
How is the fuse ?
Fuse is good.

Show me pictures of the problem PSU.
What part of the board do you need better pics of??

Need to check the capacitance of the main filter cap
Which cap is the main filter one? Is that the C203?

Checked all diodes, all good there,
Big cap is 327V DC.

stby PSU chip.
So is the stby the IC102 chip which is the MIP?
 

Thread Starter

VLCT

Joined Jun 15, 2024
29
I found a youtube vid with someone changing the MIP2K2 IC, then he bridged the R131 with a thin wire.

I tried that for a test and the board is working and charging again?


Image1.jpg
 

R!f@@

Joined Apr 2, 2009
10,004
Ya !
You tube is the one to go at times.
Keep the wire. Next time the IC shorts circuits it will blow the bridge. There is a reason for the resistor.
Bad practice might cost you.
 
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