12-22-2014, 09:12 AM
(12-21-2014, 06:48 PM)vtsteam Wrote: Bad luck!Two dead boards in completely different machines at the same time -- maybe a power spike?
At first glance that would be a reasonable conclusion. I gave it some thought and then dismissed it because:
(a) the switch on the back of the welder is a three pole single throw switch [the welder is capable of single or 3-phase input] and as you would expect, the L1 and L2 lines are totally disconnected from the plug when the switch is off. The neutral is not connected at the plug and there is no applicable place to connect the neutral to the machine. The only line connected to the house when the switch is off is the ground line and I would not think that would be an issue.
(b) the MIG and the plasma cutter are on the same circuit with similar arrangements ... when the switch is off only the ground is connected to the machines ... and both of those work fine.
© given the small number of hours on the TIG machine I suspect infant mortality more than anything else.
(d) the PC had been "acting strange" for a couple of weeks. The fans were coming on 100% much of the time, which is strange for a machine that has so little to do. I suspect that dirt and dust had finally built up [it is on 24 x 7 x 365 x 5 years] to the point where the cooling was no longer happening and something overheated. It could very well be that the section of the power supply that provides disk drive power died as I would not expect to get a POST screen if it was CPU or memory related and the drive works fine when I put it in one of the other machines, but I didn't have another power supply on hand to test the hypothesis so "its been running for 5 years so getting another everything" seemed like a good idea.
I have done as much analysis of the TIG machine as I can so now I need to make arrangements to take it [and I assume a big pot of money] to the LWS and have them look at it.
Arvid