Repairing control board on Washing machine

Thread Starter

Darry71

Joined Dec 27, 2020
7
Hi. Recently our washing machine broke and for fun I have decided to repair it. The problem appears to be in the control board. Not knowing how to properly test components on the board I did it probably not the way others would do it. With board on my desk I connected it to 240v and using my multimeter I followed the rail until I found a voltage drop. There are 2 large capacitors connected in series (both are 250v 560uf). Positive is 240v. But, where they are connected in sequence there is drop to 88v. Is that normal or is that the problem?
 

AlbertHall

Joined Jun 4, 2014
11,318
Good photo of the board might give us a clue.
When you were measuring voltages was your meter on AC or DC?
Where was the other meter lead connected to?
 

AlbertHall

Joined Jun 4, 2014
11,318
With no power on the board, and wait until those voltages have fallen to zero, connect the meter on an ohms range across each of those big capacitors in turn. You should see a low resistance gradually increasing to a high resistance. The time this change takes will depend on which ohms range you use, the higher the range the longer it will take so select a range which gives a sensible time. To repeat the measurement on a capacitor, reverse the meter leads.

Both capacitors should take about the same time.
 

Dodgydave

Joined Jun 22, 2012
9,956
What voltage AC do you get on the bridge rectifier input, and DC on the output, the two Capacitors are the half supply, there are 100K Resistors across them to discharge it .

There is a chip U241 next to the Yellow Transformer , this is the switchmode chip for the board, take pictures of it please.
 
Last edited:

Thread Starter

Darry71

Joined Dec 27, 2020
7

Thread Starter

Darry71

Joined Dec 27, 2020
7
You may find more failed components associated with your IC.
I've used these repair kits from:
L1880 LNK305GN Repair KIT Whirlpool Bauknecht Laden Ignis Dryer | eBay For Info only.
LNK623 pdf, LNK623 description, LNK623 datasheets, LNK623 view ::: ALLDATASHEET ::: For Info only.
Thanks for the links. I will change the power controller and see what happens. I don't really need the board as I have another one. I'm learning how to do this as a hobby. I genuinely appreciate the help I got from this thread.
 
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