Desktop randomly shuts off

[mr m]

I like DVM's for testing PSU's. I'm not a fan of those testers. I'd rather see a finite number than a glowing LED. I also always swap a known good PSU no matter what my meter shows. I've seen them read correctly and fail.

You must put a load on the PSU to get an accurate reading. I have two old HDD's that I have wired to a Y cable. These drives load the 5V and 12V ciruits from which all other voltages are generated.

 

[brandonkick]

Yeah... I suggested desoldering one leg to take it out of circuit. You can't accurately measure ESR in circuit,
or as others have said you run the risk of other components influencing readings and you do not want that.

And yeah again... the comment I made about the swelled up caps were that basically, I always treat swelled
caps as bad and I never assume that a cap is good just because it isn't swelled up. You need to measure the ESR
to be sure. Caps are almost a catch 22, in most cases when a cap gets old enough to go bad... the board / machine isn't
worth the repair job. Newer(ish) hardware usually never has failing caps.

Lastly, I use a trusty volt meter to test power supplies. The quick and dirty way is to just check the 3.3, 5 and 12 volts from
a PSU jumpered to run outside the case. If the values are really close, it might be ok. Testing it under load is the real test, but
if it's way off before you even put a load on it there isn't a sense in going further.

 

[MrSweet1991]

Thank you Mr m and Brandon, so I take it scrap the PSU tester, I mean if it's not really going to give you a good insight to how it's performing (and I have a multimeter) then there really is little value?

Furthermore, assume you have a volt meter to hand and you want to test the PSU under load, where exactly could you place the voltmeter ends? or did you mean in an ideal world that would be the best way?

Last but not least, I was running HWInfo64 and that provided the voltage readings from each 3, 5 and 12.. so how does that stand as opposed to using voltmeters etc?

I've mentioned it before but I'll say it again, thank you all for taking the time out to write all of this up for me. Sometimes I don't always do a direct reply to a member, but I read every post and appreciate the time and effort put into helping

 

[brandonkick]

Thank you Mr m and Brandon, so I take it scrap the PSU tester, I mean if it's not really going to give you a good insight to how it's performing (and I have a multimeter) then there really is little value?

Furthermore, assume you have a volt meter to hand and you want to test the PSU under load, where exactly could you place the voltmeter ends? or did you mean in an ideal world that would be the best way?

Last but not least, I was running HWInfo64 and that provided the voltage readings from each 3, 5 and 12.. so how does that stand as opposed to using voltmeters etc?

I've mentioned it before but I'll say it again, thank you all for taking the time out to write all of this up for me. Sometimes I don't always do a direct reply to a member, but I read every post and appreciate the time and effort put into helping

PSU testers are kinda worthless, there are equivalent to a S.M.A.R.T test for a hard drive. A failure on a smart test usually indicates a bad drive, but a pass on a S.M.A.R.T test isn't worth a crap. Same here, those LED's get lit up if the voltages are within some range. There could be enough voltage to light up that LED, but it could be still too low to actually make the computer run as it should. Maybe 11.6 volts will light up the 12V light.... but 11.6 volts might not be good enough to make the machine run stable or at all.

Lastly, if you want to test it under load, take and unfold non coated paper clips and stick one in down in a slot that has a black wire in it and one down in either an orange, yellow or red wire. Then touch your volt meter leads to the ends of the unfolded paperclip. That's the way I normally do it, just be careful when doing so.