Sync 250 issue - KA755791

[tbert]

Hi folks, I am a lurker here, and a welding hobbyist… I just purchased a used Synchro wave 250 Ser KA755791. It stick welded fine prior to purchase. I pulled it apart when I got home and I noticed these two obvious issues

A broken #177 white wire back near the fan that looks like it came off a busbar...
(The other end of white wire number 177 is attached to the lower left corner of the white box in the last picture)

And a cooked resistor/diode-looking thing beneath the blades of the Polarity-changing Switch

(Computer illiterate & will try to attach pictures)

I have many more random pictures if needed. does anyone have any ideas what these components do and if the issues are related or not? I did reattach the white wire to its original position on the busbar, but I have not run the machine since i did.
It did come with a small tig torch and a foot pedal- before purchase I tried the footpedal and heard maybe the gas solenoid(?) clicking but have not tried tigging at all. (that is why I bought this machine, to learn tig)
Thank you in advance for sharing your knowledge and expertise! This forum is a Godsend

Fyi - i'm not a Smart phone user, and i don't work at a computer - sometimes my response will be slow

[GlenC]

It's a ceramic disc capacitor

Mu guess:
RMC = manufacturer
.05uf = capacitance
Z5U = temp range

• Z = +10 °C (+50 °F) - Low temp
• 5 = +85 °C (+185 °F) - High temp
• U = +22/−56% - change of capacitance

+30-20 = tolerance %
500V = Voltage

The other box (2VK1) is a General Purpose RFI Power Line Filter

[tbert]

Thank you for replying. I don't understand what purpose these serve in the machine, tho?

Are they inter-connected? Did one cause the other to fail? Are they two completely seperate issues, wire #177 & this Disc? What is their function? What do they operate, i.e. What/where do i check? Is it minor and nothing to worry about, or - a huge problem? Sorry, I'm new to this machine, so if something wasn't functioning adequately, I'd be hard-pressed to realize it.

Where can I get one, and is it easy enough to replace?

Thank you for showing interest!

[GlenC]

Sounds like you need to get this to a qualified repair technician. They may be small parts, but they are there for a purpose and the failure could lead to catastrophic failure... Get it properly repaired!

Only someone with significant knowledge of the machine might be able to give some indication of the problems, however, significant effort is needed to trace the circuits and determine the interaction between the two components.

[tbert]

"Sounds like you need to get this to a qualified repair technician. They may be small parts, but they are there for a purpose and the failure could lead to catastrophic failure... Get it properly repaired!"

Um - this IS the Miller Forum, isn't it? The only reason I am here is to make sure that it gets "properly repaired".

Just because I don't have the money to run to the car dealer every time my cars need repair doesn't mean that I don't want it properly repaired does it?

I have followed these links for a few years, as a hobbyist.I love welding but I don't consider myself a "welder"...I am quick to correct people that ask me on the side to fix something for them because they think I am a "welder". I realize just owning the equipment does not automatically make someone a welder.

I am always surprised at how much experience the folks on this forum have, and the depth of knowledge with fixing these machines. Likewise, I have learned from them how rugged the older syncrowave 250's are,and now I have found one I can afford. I have learned here - to at least stick weld with it first before purchasing it to know that it is basically a good machine and then go from there, correct?

Using the car dealership example, I do understand that sometimes some repairs need to go to the dealership, beyond a doubt. So - if that is the general consensus here… Then I guess that's what I will need to do, bring it to the welding dealership! I just thought I would put a couple pictures here of what I discovered and see what the members here could help me with.

Anyone have any hints, or experience with these porcelain disc replacements?

[tbert]

Fyi - the Purchase;

Sync250 w/ air-cooled tig torch, foot pedal, over '100 of stick leads, '98 of 6/4 SOW power cord = $750

It stick welded way better than my Linc AC/DC 225, so I took the gamble. Seller had sent previous overall pics w/ all the sheetmetal removed, so i negected to do so myself on the rainy purchase day. Live and learn, but hopefully I still get my money worth.

My welding intentions; slowly build-up a small fabrication repair business, I'm sure in which tig will play a major part.

I welcome any advice, thank you.

[GlenC]

Cruizer will most likely have the definitive answer as to the DIY possibilities or technician repair. This probably will require some electronic diagnostics and testing...

Or replace the damaged parts and roll the dice!

[Meltedmetal]

Have you looked at the operator's manual for this machine? It has fairly complete parts and circuit diagrams if I'm looking at the right one. You can find it under resources above. Free download search by serial #. ---Meltedmetal

[tbert]

Yes, i have tried...it is extremely hard to follow. It isn't something that i am familiar with.

[tbert]

Here's what I think I'm learning...

The capacitor is there as a type of spark arrestor of sorts...it seems likely that the Polarity switch was probably thrown during welding (big no-no, now i know why!) and the result was this capacitor exploding.

The other issue of the disconnected #177 white wire seems a seperate thing.

Any thoughts?

The capacitor is only $0.47...so I can handle that!

[Meltedmetal]

Here's what I think I'm learning...

The capacitor is there as a type of spark arrestor of sorts...it seems likely that the Polarity switch was probably thrown during welding (big no-no, now i know why!) and the result was this capacitor exploding.

The other issue of the disconnected #177 white wire seems a seperate thing.

Any thoughts?

The capacitor is only $0.47...so I can handle that!

Capacitors can pass AC but block DC. I think one side of that cap is connected to ground? If that is what it does it is likely there to shunt AC generated in your DC arc to ground to protect something upstream in your machine. I haven't studied the diagrams but that may be what it is for and for $0.47 if it blows again buy 2. It may have simply shorted from old age and then burned off because it would then be trying to carry the welding current to ground. When I get time I'll have to try and find #177 on the diagrams to see what it does. Cruizer would likely know off the top of his head.---Meltedmetal

[tbert]

I'm going to give Miller a call tomorrow, I'm hoping they have better schematics for this machine...the few different versions that are included in the Owner's Manual are pretty poor reading. Do you think they will? I would pay, no problem! I usually buy the Factory Service Manuals for my vehicles because they are so comprehensive...that would be fantastic if Miller had the same for their machines.

here's hoping...

[Bodybagger]

That little "bussbar" under the fan motor you refer to is a SHUNT. It's basically a strip of metal that provides a bit of resistance and dissipates heat, hence it's location right in the path of fast-moving air next to the fan. That white wire is not #177. There is no #177 in that machine. It's wire #77. It probably worked loose due to vibration of the fan motor.

[tbert]

Thanks!!

See?!… That's what I'm talking about!

Those are the type of descriptive pictures that I wish I was privy to all along! Even if they were a pay-per-view type of arrangement it would still be so worth it.

Bodybagger, do you have any thoughts as to what the effects on the welder may be if it was operated with the #77 wire off?

[tbert]

ok, got denied at the 866-931-9732 Miller number. They state they can only send Service Manuals to LWS, and that I need to contact one of those...sigh, ok - my next mission...