I purchased a used Hobart 135 with what seems to be the very common sticking closed CR1 relay. The previous owner used it like this for two years!
The machine hums, and receives electricity to the wire even with the on off switch in the OFF position. Further, the gas valve is always on, with this sticking relay. The fan turns on, and the wire feed works once I switch the on off switch to the ON position.
After reading multiple posts, from others with the same problem, I took the cover off, blew out the insides with compressed air, and lightly tapped the two relays, CR and CR3 about ten times with a screwdriver. Thought I heard a click after that tapping.
Plugged the machine in. and guess what, no humming, no hot wire. Turned the power switch to the ON position, and the welder functioned normally. Seems to be fixed for now.
What causes these relays to stick shut?
Will this be an on-going problem?
Should I just change out the relay anyway? Or is that not necessary now?
Thanks for your input.
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