The two relays are wired in parallel - both the 24v DC operating coils and the 40 Amp contacts are paralleled. Together, they switch the main AC power through to the primary of the main welding transformer.
( Other welders have a small relay on the PCB which drives a large contactor to do that job.)
Since you can strike an arc, the transformer and bridge rectifier must be getting power, so the relays are fine.
The "uprated" board uses a different make of relay to yours, with contacts rated at 30 rather than 40 Amps. Some of the resistors have a slightly higher wattage rating, but I do not think there is any real advantage in replacing your PCB with the newer one.
Except that the new one probably works, and yours does not!
If you want to troubleshoot your own board:
Variable power for the wirefeed motor comes from a rather crude switching circuit based on the BT151 thyristor ( SCR ) on the right-hand side. You could start by removing and testing that component. Google "testing an SCR". With the flat metal tab at the back, from the left the three pins on the BT151 are: Cathode, Anode, Gate.
sako243 thank you, I will check this and report back. Thanks for your time.
I tested the motor straight from the motor terminals. Connected a 12v car charger to them.
Does it matter about polarity ?
Red to left or right also what voltage do I set the meter to say 30v in DC)?
I will let you know when I put the new BT151 Thyrister in.
Don't have my voltmeter here, it's at my sons
OK checked the continuity across the 2 thick solder points.
+ probe on the left and - on the right side.
Power on and trigger NOT pressed no continuity reading.
Power on and trigger pressed I DID get continuity.
Power on trigger pressed and NO voltage reading.
Any ideas please.
The reason you get continuity is because I suspect it's meant to be wired up something like this. I.e. either power or ground connected to the PCB and then the motor to the other terminal with the opposite of power or ground connected directly to the motor.
Conclusion is I think your PCB is working if the relays are clicking and you're getting continuity so I'd focus on chasing through the wiring to make sure it's all OK.
Just had a close look at the board again and just noticed this transistor with rusty pins.
The solder on the back looks fine, if this transistor had failed could that cause the wire feeder to not work ?