Cannot start an arc syncrowave 250

[jrnico]

Hey all,


I have an older (I believe mid year 2000) syncrowave 250 that will not strike an arc. I used it successfully on stainless using a scratch start but it does nothing on aluminum.
I adjusted the points to .008" but no there is no visual arc at all with depression of the pedal.
I read there should be an audible buzz noting the HF is working, but I do not hear anything other than the solenoid for the gas click on when depressing the pedal. Tried adjusting the HF intensity control (up to 100, down to zero) but it makes no difference. The only way I can get the points to spark is if I switch the Output-Contactor switch from remote to panel, and I see a quick blue arc jump between the points.

I read this could be a transformer or capacitor problem within the high frequency unit. I took the side panel off and found the capacitor, it has the markings .002uf 10,000V .If this capacitor is bad, are these available from miller still or will I have to find an equivalent to put in?

If there are any other things I could check for before tearing into this machine to test those components that would be great. Hopefully I am just overlooking something simple.

PS. It welds stick great, and if you scratch start it does a fine job on stainless.

serial # la302755

[cruizer]

HF transformer is likely kuput, quite common and cheap to fix

[pgk]

Good call Cruizer,
I had a Sync 250 and had the same thing happen quite a few years ago, and your right it didn't cost that much to repair.

HF transformer is likely kuput, quite common and cheap to fix

[M J Mauer]

Welcome to the forum.

[jrnico]

HF transformer is likely kuput, quite common and cheap to fix

You are talking about the HF unit transformer correct? Do you remember where you ordered yours from?

[cruizer]

Miller4less.com. You'll have to look up the part number

[jrnico]

So I went through this whole list, including visually checking all the relays. I originally thought the transformer or capacitor would be the culprit, but they test fine. The one test I couldn't do is test for the high voltage on the secondary of the transformer (3000-6000v) as I do not have the specialized equipment to do that. I also did not "check control board pc1", other than visually looking at it, I don't see anything burned out or out of place.

One thing I notice, if I switch the "output" switch from 'remote' to 'on' position, I get a split second of spark between the points.

Could anyone point me in the right direction?

[cruizer]

Just a guess, but probably the hf trasformer. Just could be the hf transformer. But you know what. Hmm, bet the hf transformer is pooched. However, if you ask again what it could be, maybe just send it into a repair shop. Bet you didn't disconnect the primary to the hf transformer and check for the 120 vac signal. No need to check the secondary

[jrnico]

what I do to keep it quick and simple, without really getting into the machine is cut or skin back wires 31 and 32 going into the HF transformer and meter them for 115 Vac when I hit the foot pedal. 115Vac present, and no Hf I know its the transformer pooched.



I skinned these as you noted, put my voltmeter on it and hit the foot pedal, I see nothing. Could you explain why this test shows the transformer is bad?

[cruizer]

what I do to keep it quick and simple, without really getting into the machine is cut or skin back wires 31 and 32 going into the HF transformer and meter them for 115 Vac when I hit the foot pedal. 115Vac present, and no Hf I know its the transformer pooched.



I skinned these as you noted, put my voltmeter on it and hit the foot pedal, I see nothing. Could you explain why this test shows the transformer is bad?

You have to cut these wires to test not merely skin them. then check if power is present with the foot pedal. Or go back to the board connector and test there. I cut them for speed, then butt connect them after.

[jrnico]

Figured it out, it was TD3, the preflow timer circuit. Seems there is a malfunction there, when preflow is turned completely off, everything energizes again and it works. If the preflow circuit is malfunctioning, it doesn't allow CR5 to activate, hense no high frequency. I will troubleshoot the preflow circuit another day, but for now I have a functioning welder again.

Cheers!