Back With A Syncrowave 250 Project

[Doug_]

Hi guys, It's been awhile since I've posted and I apologise for that.

Well I picked up a Miller Syncrowave 250 1991 Era and you guessed it I'm having some troubles with it. For now I have it hooked up to a 248 volt 50 amp circuit.
when I throw the switch the fan comes on and the machine draws about 4 amps. There is no Power Factor Correction option on this machine.
I know I need a 100 amp service for this to run properly but thought I'd give it a try to test it.

When I try to Arc Weld with it nothing happens, no arc not even a spark.

I pulled off the side cover and the jumpers are the correct terminals for 230 volts. o O-O O-O o

looking around on the inside I can see that there was some wasp or Mud Dauber nests.

I also found this wire off and dangling the number on it is Arrow Down 76 looking at the wiring diagram inside the cover it looks like it goes on FL1
which is that bent terminal above it. The lower wire is Arrow down 77. I hooked the wire back up and still nothing. At this point I'm looking for direction as to what to try next.
Any help would be appreciated, thanks in advance.

[Doug_]

I checked the spark gap on the Hi Frequency points and the left one was set to .045 and the right was set to .059
I looked up the setting and set them to .008.

[Doug_]

Meanwhile I took the foot pedal apart and gave it a good cleaning.
It wasn't too bad on the inside.

[wb4rt]

Hi Doug.

I have a Syncrowave 250, about the same age. I’m not a technician but probably one will chime in soon.

I assume you are trying to TIG, not stick. Setting the points is good, but getting that wire connected correctly is important. You will get some good assistance on here to troubleshoot but you need to indicate all the switch setting. It could be you have a remote switch or something simple set wrong. I have a document with pictures showing default settings for steel and aluminum. If you want it I will try to get it to you. It was posted on an old thread. It is helpful for a quick reference without reading the whole manual.

Edit- added link: post 6 here https://weldingweb.com/vbb/showthrea...d-help-with-HF
The picture with pointers looks odd on my iPad, it is rotated 90*. You can still read the switch settings in chart below. Maybe picture will look right on your device.


Be sure you get a copy of manual at Millerwelds.com.

Looking forward to seeing your machine working!

[G-ManBart]

Hi guys, It's been awhile since I've posted and I apologise for that.

Well I picked up a Miller Syncrowave 250 1991 Era and you guessed it I'm having some troubles with it. For now I have it hooked up to a 248 volt 50 amp circuit.
when I throw the switch the fan comes on and the machine draws about 4 amps. There is no Power Factor Correction option on this machine.
I know I need a 100 amp service for this to run properly but thought I'd give it a try to test it.

When I try to Arc Weld with it nothing happens, no arc not even a spark.

I pulled off the side cover and the jumpers are the correct terminals for 230 volts. o O-O O-O o

looking around on the inside I can see that there was some wasp or Mud Dauber nests.

I also found this wire off and dangling the number on it is Arrow Down 76 looking at the wiring diagram inside the cover it looks like it goes on FL1
which is that bent terminal above it. The lower wire is Arrow down 77. I hooked the wire back up and still nothing. At this point I'm looking for direction as to what to try next.
Any help would be appreciated, thanks in advance.

The wires coming off the silver filter (FL1) go to the shunt which is the aluminum bar below the fan motor. It will have red insulators on either end that stand out. One wire from the filter goes to each end of the shunt. If one of those wires is off, the welder will either weld minimum or maximum current, but nothing in between. If the other wire is off, I'm pretty sure the welder won't produce an arc at all. I had one where one of the wires fell off at the shunt end, and it would weld minimum or maximum, but nothing in between. I replaced it, but noticed Miller didn't secure it with a nut...it was like it was soldered in place. I checked the other end and that one fell off in my hand. I put nuts on both and everything was fine.

It may be just the picture, but the terminal on the filter looks like it may have melted, rather than just bent....hard to know for sure. If that's damaged I wouldn't expect the machine to weld.

I'm sure one of the pros will show up with more info, but that's at least something to check into a bit.

I have run about 15 different Syncrowave 250 and 250DX on a 40 amp breaker without issue...at least up to 250A output or so. I eventually bumped it up to a 60A breaker because I had the wire size to support it, but you should have zero problems on a 50A breaker.

[G-ManBart]

I just checked the manual wiring diagram and the wire I had fall off was down arrow 77, which shows as negative. Up arrow 76 is the positive lead.

I just finished going through a similar vintage Sync 250 today and will be selling it soon...I think it's a 1989 model (definitely still has the shunt), so most things should be the same if you want me to check something for you. They don't last long, so let me know!

Does the HF fire and the gas solenoid click when you press the pedal?

[Doug_]

Hi Doug.

I have a Syncrowave 250, about the same age. I’m not a technician but probably one will chime in soon.

I assume you are trying to TIG, not stick. Setting the points is good, but getting that wire connected correctly is important. You will get some good assistance on here to troubleshoot but you need to indicate all the switch setting. It could be you have a remote switch or something simple set wrong. I have a document with pictures showing default settings for steel and aluminum. If you want it I will try to get it to you. It was posted on an old thread. It is helpful for a quick reference without reading the whole manual.

Edit- added link: post 6 here https://weldingweb.com/vbb/showthrea...d-help-with-HF
The picture with pointers looks odd on my iPad, it is rotated 90*. You can still read the switch settings in chart below. Maybe picture will look right on your device.


Be sure you get a copy of manual at Millerwelds.com.

Looking forward to seeing your machine working!

Hi Burt,
Thanks for the information. I am just trying to get the welder to work. I recently acquired it and just started doing some work on the welder. It came with the welder, cooler, foot pedal tig torch and SMAW leads. Plus a whole stack of Tungstens, cups, flow gauge and packages of filler rods.

Because I haven't serviced the water cooler I didn't want to try tig welding with it, so I just tried stick welding. I have set the settings to stick weld but I'm not getting any power at the rod. I've tried all AC, DCEP and DCEN settings but nothing.

I want to try to find the Thermal CB that's supposed to be near one of the transformers. If it overheats it opens up and the machine won't weld until it cools off and resets. Maybe it's stuck open. I'm hoping it's something simple like that.

I have both the owners manual and the maintenance manual for the Syncrowave 250. the owners manual is for the serial number that mine is but the maintenance manual is for newer models I think.

Yeah I can't wait until it's up and running.

[Doug_]

The wires coming off the silver filter (FL1) go to the shunt which is the aluminum bar below the fan motor. It will have red insulators on either end that stand out. One wire from the filter goes to each end of the shunt. If one of those wires is off, the welder will either weld minimum or maximum current, but nothing in between. If the other wire is off, I'm pretty sure the welder won't produce an arc at all. I had one where one of the wires fell off at the shunt end, and it would weld minimum or maximum, but nothing in between. I replaced it, but noticed Miller didn't secure it with a nut...it was like it was soldered in place. I checked the other end and that one fell off in my hand. I put nuts on both and everything was fine.

It may be just the picture, but the terminal on the filter looks like it may have melted, rather than just bent....hard to know for sure. If that's damaged I wouldn't expect the machine to weld.

I'm sure one of the pros will show up with more info, but that's at least something to check into a bit.

I have run about 15 different Syncrowave 250 and 250DX on a 40 amp breaker without issue...at least up to 250A output or so. I eventually bumped it up to a 60A breaker because I had the wire size to support it, but you should have zero problems on a 50A breaker.

I just checked the manual wiring diagram and the wire I had fall off was down arrow 77, which shows as negative. Up arrow 76 is the positive lead.

Does the HF fire and the gas solenoid click when you press the pedal?

Hi Gman-Bart
Thanks for the information.
I saw that the wire was off and then looked at the wiring diagram. It was wire 76 that was definitely off. The terminal was bent like something hit it. I straightened it back up and slipped the connector back on. It's not burned that's just dirt that fell on it.

I saw that it went to the shunt on the wiring diagram and just went out in the garage to look at the shunt. There are 5 wires on the shunt 2 heavy wires and 3 small white wires they are all tight.

I haven't tried to see if the Hi Frequency or gas solenoid fire or click yet. I'll give it a try tomorrow.

[Doug_]

I just finished going through a similar vintage Sync 250 today and will be selling it soon...I think it's a 1989 model (definitely still has the shunt), so most things should be the same if you want me to check something for you. They don't last long, so let me know!

Thanks for the offer, if I come across something I'll definitely ask. I know that they don't last long and when they sell they hold their value. That's kind of why I jumped on this one.

[wb4rt]

For stick - Amp Adjust should be Panel, Arc Control s/b Up, and HF Off.

Just check to be sure.

[Louie1961]

Here's the technical manual which should help immensely with the trouble shooting. https://www.manualslib.com/manual/46...owave-250.html

[Doug_]

For stick - Amp Adjust should be Panel, Arc Control s/b Up, and HF Off.

Just check to be sure.

Thanks Burt, I'll double check and see how the settings are set.

Here's the technical manual which should help immensely with the trouble shooting. https://www.manualslib.com/manual/46...owave-250.html

Hi Louie, thanks for the link to the manual.

[wb4rt]

BTW Doug, I have run my Syncrowave on a 50 amp circuit for 7 years without any problems. Of course as a hobbiest I don’t need full power.

[Doug_]

BTW Doug, I have run my Syncrowave on a 50 amp circuit for 7 years without any problems. Of course as a hobbiest I don’t need full power.

Hi Burt,
I'll keep that in mind, it would save me the expense of adding another circuit for the Sw250.

I dove a little further into the welder today. There is a thermal breaker mounted inside the transformer and I needed to see if that was open or closed. I ohmed out circuit 104 and 105 on CR2 and found it to have continuity so that's good.
Next I wanted to see if I had continuity through the Output Contactor switch so I ohmed out the switch where 104 and 105 attach. nothing it was an open circuit in the on position. I jumped out 104 qnd 105 and gave it another try and still nothing. There are 4 circuits on that switch so there still might be one more of the 4 not making contact.

Next I hooked up the tig torch and the pedal. I set the contactor switch to Remote hit the pedal and had an arc at the tig torch. I think if I replace the contactor switch I might have SMAW capability.

[ccawgc]

replace all the toggle switches on the front panel if you can. Old switches cause problems.

[Doug_]

replace all the toggle switches on the front panel if you can. Old switches cause problems.

Sounds like a good idea, thanks.

[Doug_]

Back with an update.

I ordered the new switches and spark gap points.

I installed them and now have a working welder.

Thanks for everyone's help.

[G-ManBart]

Back with an update.

I ordered the new switches and spark gap points.

I installed them and now have a working welder.

Thanks for everyone's help.

Nice!

That's really the beauty of these machines....they usually aren't hard to fix and the parts don't cost an arm and a leg! The one I went through went to a new home the other day and I'm looking at another one not far from me...