On Aug 26, 7:05*pm, David Billington
wrote:
Jim Stewart wrote:
DrO wrote:
I have a Chicago (something)Plasmatorchfrom Harbor Freight and it
keeps dying on me...you kind of get to rely upon the fun tools in the
shop!

The current issue is that it will spark the pilot arc but not continue
to burn (it's like it blows it out, or something doesn't cycle...bad
transistor or relay?)...I cannot find anything about the schematics
for it and I'm tired of taking it in for 4 weeks to get a $20 part fix
and a $80 labor bill.

If you put a daub of fingernail polish on
all the parts, you'll know the one that they
replace.

I don't know whattorchyourplasmahas but mine has a Trafimet/Selco
S30 IIRC and I found out a design problem by debugging the workings when
it failed to play ball and I thought the electronics had failed . The
internal electrode is pushed back by the air pressure when the *plasma
is initialised and the repeated impact of the consumable electrode on
the back housing upset the material causing it to pinch the retracting
shaft that the electrode was screwed into, eventually the pinch was
enough to prevent the electrode going back to the start position so the
electronics didn't see *arc initiation and so no operation. Once I had
realised what the problem was a couple of quick passes with a small 3
corner scrapper sorted the burr and no further problems till the next
time but then I may know what the problem is.

I found a picture of the air cooled electrode with a consumable
breakdown...(mine is the center consumable option)

http://www.plang-daichi.com/thai/pro...met_plasma.php

On what part in the picture did you find the flaw?