Service Manual Dynasty 350

[wumpscut223]

I bought a 6/3 power cord because I noticed the unit didn't have a pig tail attached. I opened the top of the box and the manual to go with the welder. It looks like the welder is supposed to be shipped with a pigtail already wired into the welder. Most obviously it would hook to the back of the switch....

So the 700 series power cable instructions say to use the top two poles on the switch for single phase. But those are the push in and screw clamp connections. The 350 uses spade terminals.

Is the 350 the same as far as connection location goes? I will be using it single phase.

[wumpscut223]

Ok... I finally got the machine hooked up. For those of you who requested the usage stats they are - 415 hours and 135308 cycles.

I completed a factory reset per the owners manual.

Today I tested both AC and DC and found them to be functional using the Lift Arc method.

I checked and cleaned the HF points and set them to .010. HF did not work at all no matter the pedal position or AC/DC. What is my next troubleshooting step?

[cruizer]

Because the HF worked but was erratic, I'd say that PC-7 is pooched.

[wumpscut223]

Because the HF worked but was erratic, I'd say that PC-7 is pooched.

The HF never worked for me but the seller claimed that it is intermittent. Do you have any troubleshooting guidance for PC7? That is a $500 part and I'd rather change components if I am able to source them. I am comfortable soldering and testing components as directed.

Does anyone have a schematic for the PC7 board?

Thanks!

[cruizer]

I appear to be the only one with that info, but it won't help you.

Only 2 checks to make

RC1 check for 325Volts bewteen RC1-1 to RC1-3, unit on at idle

RC2 check for +15 volts between RC2-1 to RC2-2 HF off
Check for 0 volts HF on

Or 700HZ betwwen RC2-1 and RC2-2 HF on

If that is there, all is happy and you need a new PC-7 Replacing parts on this board is probably NOT a good thing. as it may dynamite the rest of the machine.

[wumpscut223]

I appear to be the only one with that info, but it won't help you.

Only 2 checks to make

RC1 check for 325Volts bewteen RC1-1 to RC1-3, unit on at idle

RC2 check for +15 volts between RC2-1 to RC2-2 HF off
Check for 0 volts HF on

Or 700HZ betwwen RC2-1 and RC2-2 HF on

If that is there, all is happy and you need a new PC-7 Replacing parts on this board is probably NOT a good thing. as it may dynamite the rest of the machine.

cruizer - Thank you for responding!

I will check those voltages this weekend (hopefully). Right now I'm out of town for work. Please confirm with welder on and set to HF start mode:
RC1-1 to RC1-3 voltage at idle is 325V AC or DC?
RC2-1 to RC2-2 should +15 VDC pedal up?
RC2-1 to RC2-2 should 0 VDC pedal down?


I don't have a scope right so I can't check the 700Hz now but I can buy a scope if need be. I'd rather invest the $500 in a scope and fix the card for $15... but I will take your advice as we work through this. Thanks!

[cruizer]

Whoops, yes DC volts

[shovelon]

Just to rule this out.

I had a 350DX delivered that would only work on lift arc. It turned out to have a Canadian board in it instead of the USA board. When the correct board was installed it worked perfectly.

[cruizer]

Ummm, Canadain boards and US boards are the same.... CE (european) boards are different.

[shovelon]

Ummm, Canadain boards and US boards are the same.... CE (european) boards are different.

Perhaps that was what it was then. A call to Miller confirmed it though. The new board cured the start problem.