ESAB LHO 150 - schematic diagram circuit board

[inajaf]

Hello everyone,


I’m looking for a detailed schematic diagram of the circuit boards for the ESAB LHO 150 welding machine.
I already have the basic documentation, but it’s not enough - I specifically need the full board schematics with component markings and ratings (diodes, thyristors, transistors, resistors, capacitors, etc.).
This is the type of diagram engineers use to repair the electronic boards.

If anyone can share it or point me in the right direction, I’d really appreciate it.


Thank you!

 

[inajaf]

The manual only mentions it briefly, but I need the full specifications and parameters for Item No. 110 – Potentiometer RP01 (0193 995 501).

 

[eddie49]

Hello and welcome to the Forum!

The ESAB manual that you attached is already a lot more useful than what is generally available - which is often nothing at all !
It has an interconnect wiring diagram, process descriptions, and troubleshooting advice. It is very rare to get full internal circuit diagrams of printed circuit boards.
If you still have the potentiometer RP01, you could get a rough estimate of the value by measuring with an Ohmmeter, even if this means dismantling it and probing at the ends of the circular carbon track.
The manual makes a point of stating that this pot must have an insulated control shaft.

 

[inajaf]

Hello and welcome to the Forum!

The ESAB manual that you attached is already a lot more useful than what is generally available - which is often nothing at all !
It has an interconnect wiring diagram, process descriptions, and troubleshooting advice. It is very rare to get full internal circuit diagrams of printed circuit boards.
If you still have the potentiometer RP01, you could get a rough estimate of the value by measuring with an Ohmmeter, even if this means dismantling it and probing at the ends of the circular carbon track.
The manual makes a point of stating that this pot must have an insulated control shaft.

Thank you.

We currently have no way to determine the resistance value (in kilo-ohms) of the RP01 potentiometer.
Unfortunately, it’s damaged, so we can’t measure it. That’s why we’re searching for the schematic.
Maybe you can suggest or if you know how many kilo-ohms it could be?

 

[eddie49]

No, I do not know the value. It could be 5K, or 100K.
Perhaps you could cut open the casing of the damaged component and measure the resistance of the track.
Maybe try to identify a PWM MOSFET gate driver chip on the control board and look for typical control pot values in the application notes for that chip.

 

[inajaf]

No, I do not know the value. It could be 5K, or 100K.
Perhaps you could cut open the casing of the damaged component and measure the resistance of the track.
Maybe try to identify a PWM MOSFET gate driver chip on the control board and look for typical control pot values in the application notes for that chip.

Thanks a lot for your advices.

 

[EBME2]

Given it is wired as a potentiometer across 10v and not a variable resistor its value probably isn’t that critical. If it was mine I’d try with a 100k or 10k linear see what happens.

 

[inajaf]

Given it is wired as a potentiometer across 10v and not a variable resistor its value probably isn’t that critical. If it was mine I’d try with a 100k or 10k linear see what happens.

Thanks for the advice