Millermatic 250 blowing caps

[welderrepairman]

I have a millermatic 250 with a KE serial #. it is blowing caps out the pressure relief on the cap smoke everywhere. when i took the side panels off. i found down by SR1 that wire #1 was not attached. i found that it it went to TP1 and to #17. i connected #1 and #17 together then thats when i started blowing caps. If I disconnect C5 the cap bank i can get dc o/p voltage at wires 3$# and #44. this voltage only last for one or two seconds. R1 is not shorted and I also removed the liner to test no change in o/p voltage. I did an scr test also they should that they would trigger. I am wonder if any has had this happen or can they tell what i should check next, any help is needed:confused:

[cruizer]

So what your saying is that you bypassed the thermal and took the board to frame ground as thats what #1 is (frame ground) the machine should of just operate normally as that TP1 is a normally closed switch. R1 won't ever short, it'll blow open though, it should show a resistance of around 5 ohms.
you've got a bad probably shorted SCR puck. Take an ohm meter and measure between the pads on each. Never the less all caps have to be changed out together.

I'd imagine that you recently bought the machine, and opened it up to see why it wasn't working, I pull this thermostat too if the customer doesn't want it fixed, only difference is that I flag it.

Yep

[welderrepairman]

well heres the Answer: I went back in and checked SR1, not shorted, so i was going to changed out the scr's but when i got SR1 out i noticed that the compression bolts were loose. so investigating further I found out that someone (an unexperienced repairman) had gotten in there before me and installed the scr's in backwards. hence the blowing of the caps when the trigger was pulled. The help you gave was useful and put me back on track. thanks alot:D