Attn: CRUIZER! Millermatic 175 dead (Power to welder-No fan-No Gas-No Arc)

[blue devil]

So the other day my Millermatic 175, which was bought around 2003-2004, die on me. I had just finished a few beads and set the torch down on the table as I setup for a few more. After a minute or two I heard a loud fuse style pop noise behind me. Checked the house fuse (OK), checked wall power (OK), checked for power into welder (OK), but the welder itself had no reaction to anything. No fan, no feed motor, no gas output, no arc, nothing.

I came across the following thread in which CRUIZER (hopefully he sees my thread) responded with the following comment:

http://www.millerwelds.com/resources...reply&p=267467

There is a transformer internal to the fan motor that supplys 24Vac for the rest of the system, it may be pooched. however if it is pooched, there is no protection on the circuit board, so two traces are generally blown off it. These 2 traces pass from one side of the board to the other and simple to repair with a couple of 24 gage wires soldered from one side to the other

Looking at my board, everything visually checked out, but as mentioned the two traces were blown off. Now I have done a good amount of prototype circuit board work and I have also made several complete wiring harnesses for racecars, so this task does not intimidate me.

My question to CRUIZER and others:
I see exactly which wires to replace, their beginning/ends, I have the proper wire guages, and I have all of the proper tools. Based on your experience, would your advice be:

1. Solder in mentioned wires
2. Replace the $36 fan motor unit: P/N 196 064 . . MOTOR, fan (230 VAC model)
3. Test welder by trying to power it up.

What are the other potentially damaged items? I have no problem taking my chances, spending $36, and a few hours to possibly repair the unit before throwing down $1000 or more for a new unit. I just wanted to know if this same scenario killed any other components that I will need to replace?

Thanks!
Jerry

[duaneb55]

Got it done yet?

[blue devil]

No, I havent even ordered the fan motor. I wanted to make sure I was understanding his statement clearly and was looking for any further advice or knowledge before doing so.

I figure if he recommends a new fan and two new traces, worst case scenario I am out $40. Its a cheap price I am willing to pay to get the welder functional so it can live another day... and buy me more time to save for a new MM211

[Miller Kevin]

Blue Devil,

I would suggest checking the fan motor with an ohm meter to see if it has failed. It is pretty easy to check, unplug the fan motor and ohm across the 2 white wires, you should see about 5 ohms and across the black leads you should see about 50 ohms.

[blue devil]

Okay I will check with my multimeter tonight and post the results. Are these resistance values indicative of a good motor or bad? I'm assuming good. What is the acceptable tolerance (+\- ? ohm) on these values?

[Miller Kevin]

Those would be for a good motor, they should be pretty close to that probably +/- 1 ohm on the 5 ohm reading and +/- 5 on the 50 ohm reading.

[blue devil]

I always test three individual times to rule out my own error...

Black: 48.3, 48.6, & 48.7 ohm
White: 2.8, 2.7, & 2.9 ohm

Im guessing it's bad... Which is good as last night I wen ahead and ordered the $40 part.

[Miller Kevin]

From your readings I would say that the fan motor is ok. The 2.9 ohms is a little low but typically if the fan motor fails you would see a dead short or an open there. Take a reading across the gas valve to see if it is shorted.

[cruizer]

No, I havent even ordered the fan motor. I wanted to make sure I was understanding his statement clearly and was looking for any further advice or knowledge before doing so.

I figure if he recommends a new fan and two new traces, worst case scenario I am out $40. Its a cheap price I am willing to pay to get the welder functional so it can live another day... and buy me more time to save for a new MM211

Fix the board, replace the fan/transformer motor, all should be ok.

[blue devil]

I will check the resistance across the gas solenoid. Depending on results I'll replace the fan motor with the new one that came in yesterday ($40 for preventative maintenance) and then rewire the board as I know I have a ton of 20-24 gauge wire from one of my last projects(scratch built track car).

Ill report back the (hopefully) positive results.

Cruizer, any idea what kind of amperage these traces are rated for? I'm trying to work in some type of preventative measure for the future. Thinking along the lines of a amperage regulator as the board probably already has a voltage regulator at the input. Just the engineering mindset thinking out loud...