Just got my hands on a cheap Cebora 150 DC TIG... Im brand new to TIG so bare with me....
First off I thought i would test to see what DC voltages i was getting between ground and electrode. Well I am getting 46.6Vdc and if i turn the dial on the front of the machine to increase or decrease power the voltage does not change at all.
So anyway i opened up the machine and the first thing i noticed was that the largest relay upon its own pcb at the back of the machine wasnt opening or closing when i either struck an arc or pulled the torch trigger. I figured it probably should, so i decided to hold it closed myself with a plastic pen and now when i try to scratch start an arc I get loads of little teeny weeny sparks that are completely quiet, and seem to fizz arround the tip radiating out about 5mm, plus I can actually lift the tip now and get it to start a teeny bright blue arc, which is very very weedy to say the least, any more than 1-2mm lift and it dies and its absolutely tiny, doesnt light up the area like a good strong arc on other tigs ive seen actually do...
Also when i was getting 46.6Vdc previously between ground and electrode, now it jumps from 46.6Vdc to 66Vdc if i hold down the largest relay with a plastic pen, and again this does not change if i turn the power dial on front of machine.
So basicaly I am going to go through each of the seperate pcb boards and test and elliminate any fault if i hopefully come accross one.
So first off can anyone help identify each of the pcbs ive got within my machine, heres the pics below, this will help me no end.
So heres the pcbs from this machine that ive removed to test. Ive not taken pics of the large transformers located in the bottom of the machine, just didnt see the point for this. ~I figure this is most deff a pcb problem, most likely the main pcb to boot whre the current dial potentiometer is located. This pot tested fine with my meter and showed varying resistance thru its sweep.
NOTE There is a large thyristor upon a small pcb board (see pic) i did read a post in the past where it was recomended to test this Thyristor, which i will do in time.
First off this board below has a big capacitor and some power resistors, plus a square capacitor and not sure what the purpose of this boards for? All components on this board tested fine out of circuit.

 

Just got my hands on a cheap Cebora 150 DC TIG... Im brand new to TIG so bare with me....
First off I thought i would test to see what DC voltages i was getting between ground and electrode. Well I am getting 46.6Vdc and if i turn the dial on the front of the machine to increase or decrease power the voltage does not change at all.

So, dumb questions. If you are new to Tig, why open up the welder? Why do you think the voltage should change when the "power" of the welder is actually amperage? If not knowing any of the first, why would you see the need to "hold the relays down with a pen"? My hope is that this wasn't a brand new welder that you just voided the warranty on. Not trying to be mean to you just trying to understand why you did what you did, to an innocent welder.

 

I hope that you now realize that defeating the controls designed into the welder by holding down the relay contacts manually is not a rational action if you do not know the function of the relay.

Rather than posting a bunch of photos (which in some cases can actually be helpful), locating and posting a schematic of the welder would be much more helpful.