Timeline for Power Supply case measures 75V?
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| Feb 18, 2018 at 23:04 | comment | added | TheComputerGeek010101001 | Unplug the power supply. Take a multimeter and take 3 measurements. Measurement 1: Line (right hole in socket) to Ground (bottom hole). You should get around 120 or so volts. Measurement 2: Line to Ground You should get about the same reading as Measurement 1. Measurement 3: Neutral (left hole in socket) to Ground. You should get about 0 volts. Post your results here. | |
| Sep 2, 2013 at 0:45 | history | edited | sawdust |
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| Aug 27, 2013 at 5:46 | answer | added | sawdust | timeline score: 1 | |
| Aug 27, 2013 at 1:37 | comment | added | user200692 | Thank you @sawdust for doing this test! Now I understand that this is apparently typical for Power Supplies (or is it only lower-quality models?). I guess most people don't realize it because their systems are grounded. One thing I'm wondering is how much power is wasted if there's a high voltage difference and low resistance, but this is not a forum. I can now get back to trying to revive this dead computer. I'd like to mark the last reply as "The Answer"; how? | |
| Aug 23, 2013 at 22:24 | comment | added | sawdust | Your house has probably always been like this, but only now you noticed it. I connected a PSU to the wall outlet through a 2-prong "cheater" plug to lift the ground pin. I measured 43VAC between hot and the PSU case, 77VAC between neutral and case, and 77VAC between ground and case. I'd guess this is voltage leakage through the AC coupling capacitors that is lifting chassis ground. I would not operate this equipment without a proper safety ground! | |
| Aug 22, 2013 at 22:52 | comment | added | Ramhound | @user200692 - All information should be contained in this single question. We should not have to view multiple questions to view your information. If you don't clarify the question this question WILL be closed as its currently not clear. | |
| Aug 22, 2013 at 18:48 | comment | added | user200692 | I think I have shown that Neutral and Hot are not switched when I said (in the linked post) "Hot - Sink = 100V". (Here "sink" is a water-sink, probably with a pipe going to ground.) I used a multimeter for this. | |
| Aug 22, 2013 at 17:34 | comment | added | Darth Android | Have you verified that the outlet is wired correctly? Use one of these. The fact that you have multiple systems measuring a hot ground indicates that either the outlet is miswired (possibly neutral and hot switched) or you have 3 different systems which all have the same defect (unlikely). | |
| Aug 22, 2013 at 17:24 | comment | added | user200692 | @sawdust, Please see my reply at this link. My reply was way too long for this character-limit. superuser.com/questions/635400/… | |
| Aug 21, 2013 at 9:11 | comment | added | sawdust | 75V AC or DC? If two PSUs have "hot" cases, then it's probably not the PSUs! If you really know how to use a voltmeter and take precautions with line voltage, then take three AC voltage and three DC voltage measurements at the AC wall outlet: hot to neutral, hot to ground, and neutral to ground. Repeat the measurements at the PSU-end of the power cord with the other end plugged into the wall socket. Be careful! | |
| Aug 21, 2013 at 1:55 | comment | added | user200692 | Not home built. Computer was working before, so I assume that's not the problem. I'd rather not unscrew the mobo right now. But even if that was the problem, how would that put 75V onto the case? At worst, it would put 12V DC, right? | |
| Aug 21, 2013 at 1:47 | comment | added | Carl B | Home built computer? Were the correct amount of stand offs used for the board formfactor (ATX, Micro, etc)? Too many may be touching something to the case and mobo that was not intended. | |
| Aug 21, 2013 at 1:09 | review | Close votes | |||
| Aug 23, 2013 at 17:30 | |||||
| Aug 21, 2013 at 0:47 | history | asked | user200692 | CC BY-SA 3.0 |