Syncrowave 250-No remote amperage control

[70Chevelle]

I just acquired a Syncrowave 250 that belonged to my uncle for most of its life. My uncle was sick with ALS for about 7 years, and recently passed last fall. He was a pro welder/blacksmith, and took care of his equipment.

I know the welder worked when he last used it, but it sat for 7 years, then was moved to an auction, and my father bought it back and it may have got a little rain on it on the ride home.(2 weeks ago)

I just hooked it up 2 nights ago, and the remote amperage control does not work. I can switch it to panel, and it will weld. I did try it on AC, DCEN, and DCEP. I tried another known-good foot control and still didn't work. I also tested mine out, and it checks out good(checked it with an ohm-meter)

I currently have the unit apart,it doesnt look like it got wet inside, and there doesn't seem to be any loose wires or burned components.

Anyone have any ideas on what else to check?

Thanks a lot!
-Anthony

[Desertrider33]

Maybe there's a circuit breaker that serves the remote outlet? Look in your owner's manual for possible location.

[H80N]

Manual/Troubleshooting

Anthony
if you do not have a paper copy of the manual, here is a link to the downloadable PDF's of the manuals all you need to do is enter the serial#

http://www.millerwelds.com/service/ownersmanuals.php

there is a schematic and troubleshooting guide in the manual, that will at least get you started...
We have a member here that goes by the handle CRUIZER, he is an exceptional welder service tech and has talked lots of people here through the big troubleshoot... hopefully he will chime in...
hope this helps
Heiti

[Bob Miller]

Check switch # 4 and #9 in http://www.millerwelds.com/om/o353u_mil.pdf
and make sure they're in the correct position.
Good Luck,
Bob

[70Chevelle]

4 & 9 are both set to remote.

I think I may pull the circuit board out next, and inspect all the components and solder joints.

[cruizer]

4 & 9 are both set to remote.

I think I may pull the circuit board out next, and inspect all the components and solder joints.

Yeah, that sounds like a great idea, now why would a control board be suddenly fry on the remote side and work in local. Hmmm, i'd go with corosion likely with the molex connectors or with the harness leading to the remote ampehnol.

Dielectric (Yep, I know I harp on this stuff, but it works!) grease in all the connections, though for the time being simply pull the connectors and reinsert them.

Pulling your board to check for a failed trace or solder joint is just dumb, as you woun't find any without alot of patience and a 5:1 magnifing lense. Likely you'll just blow it up with a static electricity pulse from your body.

[70Chevelle]

cruizer- Thanks for the warning about blowing up the board with static, but I'm well aware of how to handle static sensitive devices, it was my job for a year or so. And I did pull and inspect the board already-everything looks as good as new(aside from a little dust), no signs of corrosion, bad components or bad solder joints anywhere.

As for the “remote circuit” on the board frying and it working in local, I think that could very well be what happened. Not only did I check all connections involved, I did a continuity test and found everything is good from the components on the PC1 board, to the remote pedal, and back the board. I found there is a circuit on the PC1 that feeds the remote pedal(consisting of a op-amp, bjt, a few resistors a cap and a choke). This circuit it bypassed when amperage control is set to Panel, feeding the output of the amp control knob directly to the weld circuitry. When you set amp. control to Remote, you feed the output of the amp control knob through the “remote circuit” on PC1, which feeds the pedal, which then feeds the weld circuitry.

Now back to the "remote circuit". Its more likely for an op-amp or a bjt to fail, than it is for a resistor, capacitor, or choke to fail.

I found a replacement op-amp for $1.42, and a replacement transistor for $.57. I’m going to order both, and replace the transistor first, then the op-amp if that doesn’t fix it. If neither work, I will only be down a couple bucks, and at that point I may pay someone else to figure it out.

I will post my results after I try this out.

Thanks for the help!

[cruizer]

Are you telling me that there is no 10-12Vdc between "C" & "D" in the remote cct?.

Does "A" to "B" start the gas and power.

Since the local control determines the remote output, what is it set at?

[70Chevelle]

A and B do start the gas and power. I get about 5.6v at terminals C&D. Didn't seem to change when I varied the "local control" amperage from 5-310 amps.

[cruizer]

Check "C" &"D" for the 10Vdc pedal disconnected

[ccawgc]

check the little pc board on the back of the 14 pin socket.
After checking for the 10 volts. turn panel control all the way up.
If you have the remote control with the small cord and something was dropped on it. They will short out inside the cord. Takes the 24 volts power to ground and burns a circuit on the pc board. Easy fix. Jumper the damage on the pc board and replace the foot switch cord.

[70Chevelle]

I get 10.2Vdc across C&D with the pedal disconnected.

This has the old 5-pin socket, not the 14pin.

[cruizer]

Well actually A.B.C.D.E are the same code on both the 14 and the 5 pin. Ground is changed from your pin F to pin K on the 14 pin.


Anyhow, I believe there is a pin connector board on the back of the amphenol in the machine. you will want to resolder the lugs, or merely heat them up with the tip of a soldering gun. Very popular to fail at this point. Also check your remote switch itself, may be corroded.

This is NOT a main board problem. especially knowing that the control voltage of 10Vdc is present, and panel works

The remote end control voltage 0-10Vdc goes to the same place as the local control providing the switch is working. The local control merely then just controls the max output.

[70Chevelle]

I will check those connections again. It doesn't have a board on the back of the amphenol, there is a small board with one wire going through it about 3" away from the connector(called PC2). It only has on component, looks like a choke.

I tried a known-good pedal a buddy let me borrow, still no workie.

[cruizer]

Meter (resistance) out wire #110 on RC54-2 (control board) all the way out to the center of your foot pedal controller potentiometer. What do you have for resistance. Remote output switch in remote.

Just out of curiousity....