schematics help

[wheresmejumper]

I am trying to find a reason for a lower than specified open circuit voltage in an inverter.
i have this generalised wiring diagram and multimeter and was hoping i could basically check ac or dc voltages at different stages of the circuit and try to narrow down the fault.but no help from the diagram of what should be present where.
any clues as what way to move forward?
whats is the purpose of the 100 ohm resistor between between the + and - terminals?its obviously there for a good reason but when removed i get closer to what it should be.65 plugged in,75v removed,80v is what the output should be
cheers

 

[dan.taylor.1]

Is the resistor not there to stop any residual charge flashing say after you turn the set off and touch the torch to the return?

 

[wheresmejumper]

Could be,idhafc.
i just saw something similar on a welder generator lately to reduce ocv to be site safe/approved.stuck that one in the bin,obviously after speaking to the engineer who designed it

 

[wheresmejumper]

The smaller horizontal one is the one in question
the vertical pair seem to come from the inverter board and lead to the output transformer

 

[Jim Davey]

Selco made those machines, might be worth a chat to them. If they aren't on holiday for six weeks with the rest of Italy for whatever reason it is this time!

 

[Jim Davey]

I think I might have a service manual for that from years back, I'll have a look for you on Monday.

 

[wheresmejumper]

I think I might have a service manual for that from years back, I'll have a look for you on Monday.

Cheers Jim,i have all the literature from Lincoln.i have been humming and hawing over sending a hopeful email to selco with a couple of weeks.theyre hard enough to get info from at the best of times,even for current models

 

[Richard.]

Another fixer upper mate. You must have a grave yard for this lot of ongoing projects. Sorry can't help with the issue in question. As u well know you could fit what I know about electrics on the back of a stamp. Hope you resolve it mate decent machines those.

 

[wheresmejumper]

Cheers Richard. This is my main machine, its a dinger on stick and tig as it is.the extra ocv on stick would be sweet but i burned the bridge with my previous goto repairer.
Ill keep head scratching and hope for the best. Theres 650v dc present inside so its a cautious approach

 

[Richard.]

650 volts
I'd be giving that a wide birth.

 

[Sidewinder]

Caps first, then the bridge.
After that clock/firing pattern on the inverter.
Diagram is too blurry to help much with TBH.

 

[Sidewinder]

650 volts
I'd be giving that a wide birth.

Still low voltage though.

 

[wheresmejumper]

Caps first, then the bridge.
After that clock/firing pattern on the inverter.
Diagram is too blurry to help much with TBH.

Ill try to upload the page direct from the manual.havent figured it out yet on a tablet

 

[wheresmejumper]

This is the whole manual.cant fig out how just to upload 1 page

 

[Richard.]

Still low voltage though.

It's enough.

 

[wheresmejumper]

Page 23 is the money shot

 

[wheresmejumper]

Some photos

 

[wheresmejumper]

 

[wheresmejumper]

 

[Sidewinder]

It's enough.

It's current that kills not voltage however.
Remember this is only just above phase to phase voltage which many on here play about with with wanton regard.
We also know if this is pk-pk or RMS...

Ahh, re-read 650V d.c. is what the OP is on about, that will hurt, I have had a bump off 800V d.c and that did smart somewhat.

Still LV though.