4.2-4.3V not 5V....will it boot?

[HighYield]

I just put together a new folding rig with a known good CPU. It has a new Corsair 550VX power supply in it. When I turned it on for the first boot the fans spun up, but the computer did not post and no video signal came out. I pulled the power connectors off and hooked it up to an apevia power supply tester. It could maintain only 4.2-4.3 volts instead of 5 volts (on the 24pin connector). I checked on a PC Power and Cooling power supply hooked up the same way on the tester and it read 5 volts. The question is, will a computer boot/post with only 4.2 volts (the 12volt and 3.3 volt was ok). My vote is something is wrong with the power supply. Does this seem reasonable or is there something I might be missing.

Full system spec is
Asus P5WDH deluxe
E6700
Corsair 550VX
WD 200 GB Sata HD
Foxconn Geforce 8500 GT
Samsung DVDRW

 

[kush]

Never rely on software readings or any plugin device. A multi meter, while not perfect is the best way for the average person to get (more) accurate readings. Apevia = crap. It may be giving you a digital readout of voltages, but I'd still not trust it.

With that said though, you tried the Corsair and it didn't POST. You said you hooked up the PCP&C, but did you try hooking the system to it and booting, or just testing w/ the Apevia unit? Common sense says if the Corsair doesn't work, but then the PCP&C POSTs, the Corsair may be DOA - RMA time perhaps . Assuming the Apevia (PST-03 I assume?) is even remotely correct though, the PSU is out of spec. I forget if the ATX spec is 5% or 10%, but either way 4.2-4.3v is too low.

ps Feel free taking your time sorting this out, there's no way I'll catch you at this rate ....



[ninja] Come to think of it..You said known good CPU, but how about the other parts? All known good/tested previous or..?

 

[HighYield]

This is getting interesting....and frustrating.
Here are the known good parts (just tested them on another computer)
Good= CPU, Memory, video card
I then brought over a good PCP&C 610 watt power supply and hooked up the 24 and 8 pin cables to the suspect computer. Same thing as with the corsair 550VX. Fans spin up, but no video out and I am assuming no post (can't see anything to be sure) no speaker on this case to hear beeps.

It would seem that the corasir 550VX is probably out of spec and needs RMA'd since it's 5V is only 4.2. But now that we know it won't boot with a good power supply....I guess that just leaves the motherboard. Some of the old P5WDH deluxe boards with really old bios didn't boot with a C2D chip. I guess I might have one of those. This board is a replacement board from asus so I don't know what condition it is in (it isn't in retail packaging is all I know). I did pop the battery out and clear the cmos but that didn't help.

Anything else I need to be considering?