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Power supply shenanigans!

Posted: Fri Aug 19, 2016 1:32 pm
by Xenocrates
So, as people who bother reading my longwinded machine thread know, I still use an ATX power supply, and specifically an aftermarket one with modular cabling and tighter regulation of the lines under unbalanced loads. The reason I was sticking with that supply is now diminished, as my PT100 sensor doesn't need a PSU supplied amplifier any more, but I've got some aesthetic/random features that want it.

I went ahead and pulled all the random cabling I didn't need (Or so I thought). After this, I also pulled some cabling that went up the top deck, through the cable duct. Here's where the first obvious fail happened (I was doing this somewhat late at night, and it had been a long day). I didn't make sure that those wires, now removed from their wire nuts, were capped off properly or isolated from each other, and went to test it. (Don't do this, guys.). The power supply fan pulsed, and then cut out. The Duet and illuminated switch never came on properly. So I went looking for a cause, and found those wires. Then I called it a night after testing the Duet with a USB cable. Don't ever work on expensive electronics while you're tired.

Next morning, I tested it again, with the duet and troublesome wires disconnected. Still nothing. So I dug out the hot spare power supply. Went and connected it's 24 pin cable to the one I was worried about, and the other end to a tester. That went OK (Power good time was 330MS, long for the power supply but OK for my purposes.). That meant something was funky with my cable, so I went looking. Apparently I had missed that there were 4 V-sense wires that were connected at the contacts, going back to the power supply, which meant it wouldn't fully power without them.

I took a multimeter and made a pinout of the cable, and then some bridge wires. But I did one thing stupid when I installed them. I didn't think to flip the pinout to correspond to the side I was working from, which meant it still didn't work (At all).

Had to go and look at it again, and compare the cable side by side to figure it out. But it works now.

TL;DR, Don't be a shmuck when you muck with power supplies. Double check everything. Corsair makes very resilient models, and high end PSU's are frigging tanks.

Re: Power supply shenanigans!

Posted: Fri Aug 19, 2016 1:49 pm
by joe
Xenocrates wrote: longwinded

You got that right. Glad you got it working.