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[jjohn76]

When the machine shut off (it shut itself off?) did it reset either the power switch or the circuit breaker? When you say you put it back the way it was, did you try it again on the power source your brother used? If he had it on three phase, single phase puts a bit more stress on the input circuit....

[jjohn76]

I think about as good as you can get without an oscilloscope is the "RMS" reading from your multimeter. There were some AC specs listed for the shunt driver circuit. RC9 has a few test points that may provide info, but those are probably more informative for timing. I still don't quite understand...

[jjohn76]

It depends on the welder, but many measure the input voltage, and others even measure if three phase is connected.

[jjohn76]

Staring at the schematic some more, it sounds like back to those potentiometers... R57 looks like it controls the GTAW amperage range. At least now you have the prescribed voltage test points so you can get the duty cycle/trigger timing right on Q12....

[jjohn76]

That's interesting. I was pretty certain the Miller RFC-14 pedal has reference on the D pin. Does your pedal reference from the K pin? E-K resistance goes from 0-1k ohm?

Edit: The pedal (C-E) and panel potentiometers are just in series/parallel with the circuit that connect to the...

[jjohn76]

Something doesn't seem right. Your remote should be referenced to the board. Is socket D on the remote connected to board ground?

Also, does your arc starter work?

[jjohn76]

Capacitor C37 is a bypass capacitor to protect from transient voltage spikes. Be sure to do all of your measurements from board ground.

[jjohn76]

Also, sorry for steering you in the wrong direction on the phase control. This welder doesn't use phase control, it has a shunt winding on the main transformer to limit current like the older Dialarc and AP-B, but uses PWM (lower left of the schematic) instead of a 120W rheostat to control current in...

[jjohn76]

How did you have it wired and how long is "for a while?" What were you doing when it popped (machine idle, maxing it out, ?). First thing after waiting long enough for the capacitors to discharge is taking the cover off and taking some pictures to post here if taking it to a Miller tech is...

[jjohn76]

Looking further at the schematic, that entire top portion from the left of the page to the right just looks like it controls the HF impulse start. The voltage level sense is rectified (you measured it across R4), divided down (R5, R6) and clamped (R14, zener D10) to Keep A1 alive, then compared with...

[jjohn76]

Just trying to catch up, but to feed back what I understand so far, you measured R4 in DCEN and DCEP, and both are showing the correct polarity according to the schematic, but DCEP is lower. Something tells me it is in the upper right of your schematic instead of the upper left, as CR1 is the first...

Todd, if you send me the manual at [email protected], I'll see where I can help outt at least check.

Jon...

[jjohn76]

I can't remember if I had a schematic before, but will look around....

[jjohn76]

Looks like you'll get plenty of practice replacing multi-pin components. That Electrolytic cap is toast given its heat signature through the ground plane. If that 70V leaked through to your remote socket, it likely made it through a lot of your board. Do you have a bench power supply?

The...

[jjohn76]

Some enterprising guy started selling superflex power/water/gas hoses on eBay for a little over half the CK cost. He set up (had one made overseas) hose sets for my CK150 and CK230, we'll see how it goes. He's carrying the risk for at least 30 days, so I'm good with him owning the QC responsibility/risk...

[jjohn76]

Two of those parts cannot be repaired (234847 inverter igbt, 234846 input rectifier and boost igbt). You can usually find those for cheaper by searching Miller and the part number. The third component 245756, could be repaired, but I would only trust that repair from a company that warranties the work...

[jjohn76]

Doesn't ssc controls make a four position finger control?

[jjohn76]

What voltages do you measure across the C and K socket when you have it in stick mode and adjust the panel amperage? It should be the same voltage you see across E and K in stick mode. How does it perform in stick mode?

[jjohn76]

There aren't too many pictures available of that screen, is it a three digit, seven segment display? I wonder how many header pins it has. These LCD displays seem pretty common until you try to look for a replacement......

[jjohn76]

How are you clearing up the schematic? I think your issue is in the lower left of the schematic, where the Tig potentiometer feeds. That seems like a very narrow voltage range for your panel amperage, so that could be an issue too. I don't think those two circled board potentiometers do much other than...