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Electronics => Repair => Topic started by: rodrigopires on March 20, 2023, 10:38:51 pm

Title: miller xms 403 current sensor
Post by: rodrigopires on March 20, 2023, 10:38:51 pm

I'm repairing a miller xms 403 welding machine that displays help 1 error, that is a fault in the input current sensor. I looked around and everything looked ok. Disconnected j2-1 from the board and the error disappeared, but when I connect it again the error pops up. What could be causing this? 

White wire is phase and black wire is sensing.

Title: Re: miller xms 403 current sensor
Post by: peb on March 21, 2023, 04:00:33 am

It looks like your board is partially damaged (left to L1-2 clamp). Can't some copper tracks on the other side be broken?
I would check the foil capacitors on the board.
I have solved a problem in the past where the capacitors degraded over time and only had about half of their original capacity.
The image is not sharp, probably to the right of the POS label (prime suspect..) and above R7 label.