Milwaukee M18 Rapid Charger Repair

Thread Starter

JoeCK

Joined Mar 20, 2020
18
Hello All,

This is my first post on this forum and hopes to find some valuable input on the situation.

I have attached images of the charger circuit board herewith.

It's not charging from yesterday, so I opened it up only to find some dust and debris around the components. Then cleaned everything up using cleaner still no luck.

However, after the cleaning, the TOP256E seem to be fried :(

(while switching on, heard a tick sound and TOP256E heatsink was too hot but not sure why/what caused it!)



Please advise me is there anything could revive the charger.

Thanks a lot in advance for you guys to help.
 

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Thread Starter

JoeCK

Joined Mar 20, 2020
18
Datasheet for Top256e.. if its blown its probably gone over current mode,
Check the bridge rectifier for shorts , and input fuses, the Green Ntc near mains lead.



https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.mouser.com/datasheet/2/328/tophx_family_datasheet-1511305.pdf&ved=2ahUKEwj8qJO6wqvoAhXAXhUIHUXxDCoQFjADegQIBBAB&usg=AOvVaw2HNuoDaP4xalr5yzBjj8kK.
Thanks, Dave.
I'm a Software guy rather than an Electronic Engineer.

I would appreciate if you could let me know the "bridge rectifier, input fuses".
Kindly mark/circle the components in the pic, so I can make sure I'm checking the right parts and post back pls.
 

Thread Starter

JoeCK

Joined Mar 20, 2020
18
The TOP256E may have died, but before replacing it the four diodes on the underside of the board:
View attachment 201977
Thanks Hall, for the reply.
Yes, it is dead. Because I could see a dark brownish streak across it which was not there before :(

is that the 4 MOSFETs in the picture you mean?
or on the other side of the board can not find any four diodes together...

Is it possible to show it in the other picture, please
Or not visible, I can load a detailed picture of any area on the board if you want.

Thanks.
 

Thread Starter

JoeCK

Joined Mar 20, 2020
18
Thanks Dave,

Do I need to remove them in order to be checked? or on the circuit is fine? (capacitor, bridge rectifier, mosfets etc)

As per the picture they are MOSFETs.
 

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Thread Starter

JoeCK

Joined Mar 20, 2020
18
Hello Dave,
Sorry for the delay. (had to learn from youtube to read some of the tests and remove the components from the glued PCB)

1. The KBL406 bridge rectifier readings;
Multimeter (-) → Rectifier (+) and Multimeter (+) → Rectifier (AC) = 0.557
Multimeter (+) → Rectifier (-) and Multimeter (-) → Rectifier (AC) = 0.564
Multimeter (-) → Rectifier (+) and Multimeter (+) → Rectifier (-) = 0.485 (not sure if this reading is right)
Multimeter (+) → Rectifier (+) and Multimeter (-) → Rectifier (-) = OL

2. The 2 x 330µF 200V caps readings;
306.0µF and 306µF

3. The NTC readings;
3.0Ω

4. For the MOSFETs, GDS readings seem ok for ON and OFF states. Also damaged one of them in the process of desoldering ;(

Do you think these readings look normal? I value your advice and what could be wrong, please?
 

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AlbertHall

Joined Jun 4, 2014
9,644
Multimeter (-) → Rectifier (+) and Multimeter (+) → Rectifier (-) = 0.485 (not sure if this reading is right)
This is not right. Try with multimeter (-) to rectifier (-) and multimeter (+) to each of the rectifier (AC) contacts. They should both read 0L but I expect one of them will read very low indicating a shorted diode.
 

Thread Starter

JoeCK

Joined Mar 20, 2020
18
This is not right. Try with multimeter (-) to rectifier (-) and multimeter (+) to each of the rectifier (AC) contacts. They should both read 0L but I expect one of them will read very low indicating a shorted diode.
Hi Friends,

I have gone through the rectifier as you mentioned. The reading as follows;
Multimeter (-) → Rectifier (+) and Multimeter (+) → Rectifier (AC-Left) = OL
Multimeter (-) → Rectifier (+) and Multimeter (+) → Rectifier (AC-Right) = OL

Then I have removed the bridge rectifier from the circuit, then it reads;
Multimeter (-) → Rectifier (+) and Multimeter (+) → Rectifier (-) = 1.044
Is this reading, good?

I'm attaching the image of TOP256E removed, to verify if it's gone or not pls. Any idea how it's checked?

Is there any shop where I could get/order all the components (9561GH, 6677GH MosFets and TOP256E) in the UK pls?

Thanks a ton for your advice.
 

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AlbertHall

Joined Jun 4, 2014
9,644
Those first two readings don't tally with the earlier ones. When you check a bridge rectifier you should check each diode individually. So check from a DC pin to an AC pin (four combinations) and preferably in both directions. Each doide should show around 0.6 in one direction and 0L in the other direction.
1585325264888.png
 

Dodgydave

Joined Jun 22, 2012
9,082
Hi Friends,

I have gone through the rectifier as you mentioned. The reading as follows;
Multimeter (-) → Rectifier (+) and Multimeter (+) → Rectifier (AC-Left) = OL
Multimeter (-) → Rectifier (+) and Multimeter (+) → Rectifier (AC-Right) = OL

Then I have removed the bridge rectifier from the circuit, then it reads;
Multimeter (-) → Rectifier (+) and Multimeter (+) → Rectifier (-) = 1.044
Is this reading, good?

I'm attaching the image of TOP256E removed, to verify if it's gone or not pls. Any idea how it's checked?

Is there any shop where I could get/order all the components (9561GH, 6677GH MosFets and TOP256E) in the UK pls?

Thanks a ton for your advice.
Ebay is best place..
 

Thread Starter

JoeCK

Joined Mar 20, 2020
18
Ebay is best place..
Thanks Guys,

The order seems to arrive only after 3 weeks from ebay. It seems no one sells these components near enough to reach me by 48hrs delivery :(
Will update you as and when I receive these and jump-start the unit (hopefully )

Thanks again and I can't stop to update you on the results.

Cheers,
 
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