Shopmaster 300 AC/DC Troubleshooting Help

[txpaul57]

Hi,
I was wondering if someone has ever had the issue I am having with my Shopmaster 300. I was welding on a Friday and all was good, came in Saturday and not welding. Was running S32P, so first thing i did was troubleshoot the wire feeder but could not find any issues. so I tried stick and no arc at all. So after looking in a few forms and seeing the main issue might the CR1 or PC1, I replaced CR1 with OEM part, still no fix. Pulled PC1 out and looked for blown components, burnt spots or cracked tracing and still not seeing any issue. Called local repair shop and they said to test PLG55 pin 5 for 10V, was 11.3. Then tested PLG51 pin 1 & 2 for 18V, was 19.4. If I had voltages at these points then more than likely PC1 issues. Also checked TP1 which had continuity.

So knowing I didn't need to spend 800.00 on new PC1, I located and checked out a company 3E Services in Tucker GA, highly recommended, that had repaired many of the Miller 155826 boards. Called and spoke to them and received estimate, sent in for repair. Received back with a list of components replaced.

Installed board this morning and still same issue. So I tested SR2 for the heck of it..... But do not know where to go from here. Is it possible for the repaired board to not really be repaired? Never know unless I replace with a new one, but if not PC1 then I spent 800.00 for nothing, plus the repair cost of board.

I have gone as far as I can here, any suggestions?

Paul

[cruizer]

Hmm, same question you posted earlier, and without the freaking serial#, WE CAN'T HELP YOU

[txpaul57]

Sorry for the double post....... searched for it earlier, but couldn't find so I posted as new post. Serial # is KD408969. Have also tested HD1, Pos to Neg 1640 ohm, 1.5M Pos or Neg to #2 pin.

Paul

[cruizer]

Sorry for the double post....... searched for it earlier, but couldn't find so I posted as new post. Serial # is KD408969. Have also tested HD1, Pos to Neg 1640 ohm, 1.5M Pos or Neg to #2 pin.

Paul

Problem was likely NEVER your circuit board nor anything else other than the following.

So pick one:

Failed TP1 secondary transformer thermal, should be a closed circuit between CR1 wire 101 and RC54-10 wire 101 --very likely-- you can bypass it if its the problem.

Failed f1 fuse, center left bale assembly possibe if you have very little spark

[txpaul57]

Checked TP1, located in T1, is closed circuit. Schematic OM-318 PG 20 not showing 101 from CR1. I just traced the wires frin TP1 to termination point. CR1 only list wires below. Looks like 104C on CR1 is the mate to is RC54-10 wire 101. None the less, TP1 is closed.

104C(IT-C) #4
105C(IT-O) #7
35A(RC1-J) #A
34A(RC1-B) #8
4A(Baff GND) #B

F1 is good tested out of socket with meter and also swapped spare below it. I actually have no spark at all.

Paul

Problem was likely NEVER your circuit board nor anything else other than the following.

So pick one:

Failed TP1 secondary transformer thermal, should be a closed circuit between CR1 wire 101 and RC54-10 wire 101 --very likely-- you can bypass it if its the problem.

Failed f1 fuse, center left bale assembly possibe if you have very little spark

[cruizer]

Does the fan come on full blast or does it seem kinda lower than normal.

[txpaul57]

The fan runs as it did before this issue. Blowing full blast ....

Does the fan come on full blast or does it seem kinda lower than normal.

[cruizer]

Well then it comes down to that one of your limit switchs has failed

[txpaul57]

Checked LS1 and LS2 at switch and termination points and all check ok.

Paul

Well then it comes down to that one of your limit switchs has failed

[cruizer]

Not that I don't trust your t-shooting Techniques, but your best to take it in for service, perferably someone that holds a Miller CST cert.