I found a shop going out of business that has several welders for sale so I bought the 251. Works great with a new tweco gun and 2 big rolls of wire. Only thing wrong is the digital display is not functioning.

$700 :smokin:

Anyone have a source of parts for these so I can get a replacement display ?

BTW, they have a real nice MM300 3 phase unit if anyone can use it. They are asking $1100 .

Just so you know there could be more wrong than just the display board .

the display board might not be getting the signals from the control board

could be a loose ribbon cable .

If you can weld and see the display board your much better then me.

If you want to try changing the board Pm me the serial number I see what it would cost. take it from there.

I say if it works don`t mess with it.:grinpimp:

Good score anyway good luck

I run a 251... how could you weld without the display? There's no marks on my knobs that would show what position they are in at all... I hope it's an easy fix for you, or your $700 might cost you more than what a new one would.

Some random thoughts of my own have me looking at the block diagram from the Miller 251 manual right now.

Looks like the display is *just* a display, has a whole 4 wires connecting it to the main PCB (transmit, receive, power, ground). I'd look for a loose wire inside. The 251 looks to have 'analog' voltage/speed controls (they're potentiometers), as opposed to the 'digital' controls of the 252. So technically, you don't *need* the display to weld with the 251, the pots will work without the display, and you could make your own marks on the panel based on pot rotation... but you might open 'er up just in case and see what you can find. Then again, there has to be some sort of microcontroller on the display board, so it could be zonked, but that shouldn't affect welding.

The controls work just like my MM175 so the display is just a display. You are correct, it just has a 4 pin molex connecting the display board that does have a processor on it. The shop had put marks for the setting they used. I took the board out and I am running it over to Miller to see if they can troubleshoot it.

Either way, it was a hell of a deal.

Some random thoughts of my own have me looking at the block diagram from the Miller 251 manual right now.

Looks like the display is *just* a display, has a whole 4 wires connecting it to the main PCB (transmit, receive, power, ground). I'd look for a loose wire inside. The 251 looks to have 'analog' voltage/speed controls (they're potentiometers), as opposed to the 'digital' controls of the 252. So technically, you don't *need* the display to weld with the 251, the pots will work without the display, and you could make your own marks on the panel based on pot rotation... but you might open 'er up just in case and see what you can find. Then again, there has to be some sort of microcontroller on the display board, so it could be zonked, but that shouldn't affect welding.

Is it just me or does $700 seem like not that great a deal?

paid 1700 for mine new...

Is it just me or does $700 seem like not that great a deal?

It is just you. These are still selling for $1200 - $1600 . A new 252 will run you $2000+ , the best deal I found was $1985 + Tax.

BTW, I will be able to get $600 for my MM175

Fair enough.