Sync 250DX HF Start Problems

[Helios]

Hey, all,

I have a 2010 Syncrowave 250DX that I bought new (stock number 907194-03-2 with serial number prefix MA) five years and six months ago that suddenly has some problems with HF start. (Machine has very low hours, as I am still just a hobbyist.)

If I put it in DCEN and HF Start, it won't start the arc. I also noticed that although I can hear something activating in the machine when I hit the pedal (it sounds like big caps being charged or discharged), the overhead fluorescent tubes don't "flicker" like they used to always do when I hit the pedal. However, if I scratch-start with it set this way, it will weld, and I do have pedal amperage throttle control.

If I put it in AC and HF Continuous, same deal: It won't start when I hit the pedal, but if I hold the pedal down, I can scratch-start, and it will start and sustain the arc, so I assume the HF is working continuously, otherwise, it wouldn't be able to sustain the AC arc, right?

I welded for a minute or two in AC with HF continuous, thinking that maybe the dew in my shop had gotten into the HF points, and maybe running the HF on continuously would dry them out, but that didn't seem to make any difference.

Then I went back to DCEN and set the HF to continuous. Tried to start using the pedal. No go. Scratch-started and welded that way for a minute or so, hoping that the HF on continuous would dry out the HF points, but again, it didn't do any good.

I verified:
– Argon on (and yes it's straight argon, I've been using this bottle successfully for months)
– Everything in torch is tight.
– DINSE connectors tight.
– Good ground on work clamp (I also tried to light up directly on the work clamp)
– Tried a few different tungstens, and a few different collets and collet bodies. No love.

Can anyone give me any clues on how to diagnose or fix this machine? My LWS is 70 miles away and getting this beast to them would be a nightmare. Thanks in advance.

[H80N]

Have you cleaned and regapped the HF spark gaps??

See Section 5-3. "Adjusting Spark Gaps"

Page 49 (Page 55 of the PDF)

https://www.millerwelds.com/files/ow...O363AF_MIL.pdf

BTW... lots of old threads on the subject ...

[Helios]

Have you cleaned and regapped the HF spark gaps??

I opened it up and inspected the spark gaps once maybe a year ago, but everything looked factory-fresh and to spec. Probably less than two hours of arc time on the machine since then...but I guess that's the next thing to check. Wish it wasn't such a hassle to go in there...much easier on my 330A/BP if I recall correctly.

Thanks for your reply.

[H80N]

I opened it up and inspected the spark gaps once maybe a year ago, but everything looked factory-fresh and to spec. Probably less than two hours of arc time on the machine since then...but I guess that's the next thing to check. Wish it wasn't such a hassle to go in there...much easier on my 330A/BP if I recall correctly.

Thanks for your reply.

It does not take very much dust and crud to short them to ground

just bit of High Voltage leakage can kill your HF arc starts

Besides cleaning them i quick and easy

[Helios]

OK, thanks. I'd bet that's what's wrong -- dust combined with the dew. There was dew on the top of the welder, and I'm sure there's probably dew inside (crazy weather here this winter). Thanks for your help.

P.S. In doing a search for similar threads, I found this, which I had not heard about before (reposted here for posterity):

Woodweld1
I know this is an old post, but a mentor of mine showed me how to clean the points. You depress the pedal and when you see the it arc across the points you take a pc of paper and slide it across the point while there arcing (be careful) I do that once a month to my machine and it works. I know it doesnt sound safe, and I thought he was trying to prank me, but he took the time to do it himself and show me how. Not saying this is your problem but it does smooth out the HF I have an older 250 syncro and when you lift the bottom cover the point are right there in plain sight so its easy to do.

cruizer
Yep the paper trick works wonders to clean the points. your unlikely to get zapped as paper is a great insulator. The hf spark bounces back and self cleans itself without loss of the points coating making for a significantly better signal.
Physically cleaning the points with a wire brush or sand paper removes the coating. This doesn't help the hf spark much and makes it become erratic very quickly.:

[H80N]

OK, thanks. I'd bet that's what's wrong -- dust combined with the dew. There was dew on the top of the welder, and I'm sure there's probably dew inside (crazy weather here this winter). Thanks for your help.

P.S. In doing a search for similar threads, I found this, which I had not heard about before (reposted here for posterity):

Woodweld1
I know this is an old post, but a mentor of mine showed me how to clean the points. You depress the pedal and when you see the it arc across the points you take a pc of paper and slide it across the point while there arcing (be careful) I do that once a month to my machine and it works. I know it doesnt sound safe, and I thought he was trying to prank me, but he took the time to do it himself and show me how. Not saying this is your problem but it does smooth out the HF I have an older 250 syncro and when you lift the bottom cover the point are right there in plain sight so its easy to do.

cruizer
Yep the paper trick works wonders to clean the points. your unlikely to get zapped as paper is a great insulator. The hf spark bounces back and self cleans itself without loss of the points coating making for a significantly better signal.
Physically cleaning the points with a wire brush or sand paper removes the coating. This doesn't help the hf spark much and makes it become erratic very quickly.:

I would clean the area round them as well... as the "paper trick" does not help if you have leakage to ground...

blowing the machine out with the covers off is not a bad idea either

[Helios]

It does not take very much dust and crud to short them to ground

just bit of High Voltage leakage can kill your HF arc starts

Besides cleaning them i quick and easy

Well, that was it. Thank you for your spot-on and fast reply.

I took out the 30 or 40 machine screws and sheet metal screws and bolts necessary to access the points and hit the pedal, and sure enough, all I got was a yellow spark on one of the gaps. So I cleaned the ends of the points by squeezing paper (wetted with electrical contact cleaner) between them and dragging it through, and some black stuff came off one of the points. I guess maybe this was carbonized dust or sawdust or something.

I reset the gaps and fired it up again, and the blue sparks returned. Tried to weld with it, and all seems back to normal.

One question for the techs here: Since the point gaps seem to get smaller over time, due to carbon building up and whatever, and since the manual for my 330A/BP says that you can get more reliable arc initiation if you increase the length of the spark gap, would it be wise to increase my spark gap from the recommended .008" to .010" ? Even if it wouldn't help, is there any chance it could harm anything? Because I'm tempted to try it.

Thanks again.

[H80N]

Well, that was it. Thank you for your spot-on and fast reply.....


One question for the techs here: Since the point gaps seem to get smaller over time, due to carbon building up and whatever, and since the manual for my 330A/BP says that you can get more reliable arc initiation if you increase the length of the spark gap, would it be wise to increase my spark gap from the recommended .008" to .010" ? Even if it wouldn't help, is there any chance it could harm anything? Because I'm tempted to try it.

Thanks again.

Some folks run as much as .012..... I would leave it at factory spec....that choice up to you...

One thought for the future... many times hard TIG starts are due to crappy ground connection... the factory supplied tin clamp leaves a lot to be desired... the cast bronze clamps give much better service...

[Helios]

Yeah, that's actually the work clamp I use. I also took some copper wire that I stripped out of a piece of Romex and used the tig torch to melt/braze it onto the leg of my welding table where the clamp contacts the steel, which reduced resistance even more (also did that to the legs and tips of my "third hand" gizmos)