High Frequincy start up problem DYNASTY 300 DX

[MrRogue]

High Frequency start up problem on my Dynasty 300 DX. (AC / Aluminum) High frequency start-up at the start of the an arc just pulses continually.Sometimes if I stop and start again it will make the high freq pulsing start the jump in to an arc like it should.This high freq start pulsing isn't right.This problem is with AC while welding aluminum.The past four months I've been using the machine to DC weld mild 16 gauge steel and I've not have one problem.I've had TWO guys come look over the machine trying to figure out the troubles.One friend that owns a biz where he an his father have welded aluminum for over 50 years...The second guy in a Welder Tech guy from our local AirGas store.He lives close so he came by and checked the points, moved further apart, moved closer together. We swapped out the foot peddle with a know good one to see if the trouble was trouble, ...it was not.I have a long extension cord/cable from the main barker to the machine.The cord is a 10/4. It's around 100ft long.The machine (300DX) came with 10gauge wire power cable so I matched it.Thinking the cable might be causing the problem, we talked through it. The high freq uses large Voltage to Start the arc, not Amps. So with that thought, the long extension power cable isn't the problem.At this point we are looking at the High Frequency board with the points gap on it. Changing the Gap didn't do anything to curve the problem. We are thinking the problem is in one of the circuit components on that high freq board.Board: C7 PN: 189 137Anyone with any ideas ?MrRogueRogue Racing[email protected]

[cruizer]

Yep might be the high freq board, unlikely as boards generally don't work if there is damage plus there is a protection fuse on that board. Might be a tig torch about to fail as well.

And just cause the caps and hf transformer build up a charge means pretty much zip if the cable length is too long with a under size primary. Takes power to make the auxillary, plumb that low power to DC which now is even lower which runs the boards. So now we have low power, which equates to heat.

If your using twist lock plugs on your cable ends, might want to take them apart and tighten the internal screws.. Never the less 10/4 is simply too small on that long of run.

[Tryagn5]

Yep might be the high freq board, unlikely as boards generally don't work if there is damage plus there is a protection fuse on that board. Might be a tig torch about to fail as well.

And just cause the caps and hf transformer build up a charge means pretty much zip if the cable length is too long with a under size primary. Takes power to make the auxillary, plumb that low power to DC which now is even lower which runs the boards. So now we have low power, which equates to heat.

If your using twist lock plugs on your cable ends, might want to take them apart and tighten the internal screws.. Never the less 10/4 is simply too small on that long of run.

Yup..10-4 is very small...unless he has 460 volts. Still be questionable. I would move the welder closer to the power and see what happens. Also would check the voltage.
Kevin

[MrRogue]

Thanks for the reply's,I will look into the cost of getting the 8/4 extension cable.I'm using single phase 200 amp service here. 240vI will check the click lock cord ends. good idea, it's been a while sense I check those.

[MrRogue]

...also...Cruiser I did replace the entire torch and leads about four months ago.20mm tig torch.

[MrRogue]

still no luck with this issue on the 300DX.I have called and talked to the Miller Techs, places that trouble shoot and rebuild pc boards for welding machines.Local tech has really put a lot of effort into trying to figure this out as well. We have not figured it out.I open to any other suggestions, if there are any new ones....Thank,MrRogue

[cruizer]

Has to be the HF board, its a separate unit mounted under the top board left side. May just be a corroded connection, or corroded posts on the fuse.

As the board works, this is all I can come up with.

What you can do is hook it up, remove the cover, turn off the light and hit the pedal. Maybe there is a short inside the unit, never know....