Need help with no start on a Chinese welder, Amico S-185 multi-process

Thread Starter

Raylicker

Joined Nov 14, 2019
2
Hi all, I left it on for about an hour and when I got back it was off and never to start again. The power light goes on but nothing else. The switch is good. Only had the thing for 1 year and then one month after the warranty expired it died. Thank you for any help with troubleshooting PCB's. I'm getting power to the capacitors but don't know where o check after that. Here are pics of the two boards in it. Could it be on the little board? if I am getting power all the way to the capacitors, shouldn't I have front panel lights or something? Please any help, here are pics of both boards
 

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drc_567

Joined Dec 29, 2008
732
... You might take a look at the blue disk parts, in the heat sink photo. It looks like they are metal oxide varistors:

If one is shorting out, it may be warmer than the others. (First turn power off if testing with finger.)
The other option is:
Desolder and check to see if the conductivity is uniform and consistent.
 

Dodgydave

Joined Jun 22, 2012
8,466
The 8 pin chip that pulses Q1, to Q4, is the Switchmode psu, if this isn't working then nothing will power up, you need to check the Voltages from T1 and T2 Outputs and from the bridge rectifiers.
 

Thread Starter

Raylicker

Joined Nov 14, 2019
2
The 8 pin chip that pulses Q1, to Q4, is the Switchmode psu, if this isn't working then nothing will power up, you need to check the Voltages from T1 and T2 Outputs and from the bridge rectifiers.
I'm not sure if am testing right but I tested on the back of the board there is a glob of solder under both t-1 and t-2, is that what I test? If so I'm only getting about .2 dc volts. I marked where on attachment. Can you tell me by looking at other attachments where I plug in the fan, the gas valve, the wire feed, and the two wires that come off the mainboard? It has been about a year since I took this apart and not too sure where they go. Thank you so much for any help.
 

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