Relavant specs used in testing:
Motherboard - Asus P5Q-E (Tested and maybe damaged 2 boards now)
Processor - Intel E8500
RAM - 4GB Corsair Dominator DDR2 1066
Case - Silverstone LC-16M HTPC Case
Video Card - PaLit 4850 PCI-E
PSU #1 (probably now defective in some way) - Silverstone Zeus 650W
PSU #2 (Unknown status) - Antec Trio! 650W
PSU Tester - http://www.xpcgear.com/ps224.html
I'm having a problem with a new build where the computer works fine initially but after some usage and after reapplying power (by unplugging or switching off), the computer will not turn ON. If I leave it OFF for awhile or if I unplug some power cables, it eventually starts working again.
One thing to note (and this is my fault but also due to bad directions in the manual), is that I connected the VFD on my case incorrectly. The HTPC case has an attachment that needs to go between the ATX 24-pin connector and the motherboard. The pinout is the same except that 3 wires hang off the connector and go into the VFD (See connector: http://c1.neweggimages.com/NeweggIma...163-053-09.jpg)
PSU adapter (referring to 3 wire portion) --> VFD (power switch) --> Motherboard Power Switch
Case power switch --> VFD
**HTPC cases are setup this way so that remote control can send a IR signal to the VFD and turn on the computer**
INCORRECT Connection (I connected it this way 2 times and this MAY be the source of the problem):
PSU adapter (referring to 3 wire portion) --> VFD (Power switch) --> VFD (Power switch)
Case power switch --> Motherboard Power Switch
**There are 2 sets of power switch wires coming off of the VFD. One should connect to the motherboard and the other should connect to the case switch. I connected the VFD power switches with each other and this MAY be the source of the problem (again, my fault). I don't know if the VFD power switches are looped inside the VFD but if it is, this means that ATX wires would be crossed since these 3 wires essentially connect with the main atx 24-pin connector.
I did some extensive testing after reapplying power (this is when the problem is happening), and found that the following:
TEST #1 (Asus P5Q-E, Silverstone PSU)
-The ONBOARD power and reset button LED's on Asus motherboard blink(NOTE: The LED's on these ONBOARD buttons work similar to regular LED's found on other motherboards. They remain ON during standby). I called Asus and they said that the LED's blink when there is something wrong with the power...possibly a bad regulator on the motherboard or PSU
-The Silverstone Zeus 650W PSU makes a ticking noise when this problem is happenning. The reading with a multimeter is a highly fluctuating -1v voltage drop below the +/-5% normal range.
-After all of this the Silverstone PSU, still ticks even when nothing is connected to it. The PSU tester shows low voltages all around. The PSU eventually returns to normal with normal voltages all around but this takes awhile.
-I ran the Silverstone PSU running for awhile with ONLY the PSU tester (no mobo...nothing...just the tester), then disconnected and reapplied power. The same low voltage problem happens. This is why I think the Silverstone PSU is now busted.
TEST #2 (New/Replaced Asus P5Q-E, Antec PSU, same cpu/ram/video)
-Side note: I noticed that the starting voltage of the Antec Trio! is ~+3.52v on the +3.3v rail. Acceptable ranges are usually 5% or lower (+3.47v). This starting voltage lasts for 1 second or less then drops down to +3.3v right away. In effect, my Asus' mobo LED blinkings once then stays solid. Is this starting voltage normal for some PSU? Can ~+3.52v damage anything on the motherboard? FYI...I actually went through 2 Antec's and have the same "high" starting voltages.
-When doing this test with the new mobo and psu, I unfortunately connected the case/vfd/mobo incorrectly (I hadn't realized this problem yet). This may have led to another problematic PSU.
-The mobo LED's blink in the same way after the same reapplying of power...except no ticking noise from the PSU. Computer does not turn ON.
-I returned the Antec PSU's before I can do any voltage testing or testing with just the PSU tester alone (nothing else connected).....but from the way things were looking, the resulting voltages would probably be the same/similar.
From my tests, I concluded that the PSU becomes damaged after touching one or more of the components...or incorrect case connection. I also concluded that one of the following may have happenned...
1) My incorrect connection busted the PSU(s) or more in some way 2) There's something going on with my house electrical where voltage drops abnormally after applying a certain load 3) My motherboard, CPU, or video card is damaged in such a way where it did something to the PSU's regulators or other PSU parts.
Are any of the above true or can some be ruled out?
I'm getting RMA'd case, PSU, and motherboard but a main concern of mine is that I may have not yet identified the source of the problem...and the problems/damages will happen again. Can defective CPU, RAM, video card cause a PSU to go bad OR cause the mobo to go bad and eventually the PSU (chain reaction)? I want to make sure that when I get the spare parts, none of this happens again. Another side note: I tested the latest RMA'd mobo with an Antec PSU that went through all of this. It did not go through the incorrect case connection. I'm hoping that nothing is broken on that board.
Should I test anything else or does anyone have any ideas of what's going on?
I've troubleshooted this problem for HOURS for the last couple of days and could not make a solid diagnosis...Not to mention the RMA headache. This has got to be THE worst i've come across after many years of building computers.
The green LED on Asus boards indicates the status of the 5v standby voltage rail. If it is blinking, the 5vsb rail is pulsing. If it is off, the voltage level on that rail is below the trigger voltage of the LED. One (possible) way to to circumvent/test this is to turn the power off with the PSU switch, wait 5 seconds, flip the power switch back on and then immediately push the power button.
It's hard to visualize the connections you describe. Obviously, connecting the case power switch to the motherboard power switch header won't cause any problems. A picture of the other parts, connected, would give me a much clearer idea of whether it could damage the power supply.
Sorry, I messed up the connections description on my post. These pictures shoulds explain it. The case is in process of being exchanged so I can't confirm exactly what 3 ATX pins are being used for the VFD.
From the description of the function of the VFD, the wires from the PSU to the VFD were the +5vsb and ground. Depending upon the resistance inside the VFD, wiring it the way you did could possibly be close to a short circuit. If it had been a short, the power supply should've shut its outputs off immediately (or never turn them on).
So, yes, I would say it's quite possible that mis-wiring could be cause and that both PSU's are likely damaged. Also, I wouldn't recommend running a power supply with the PSU tester, and no other load, any longer than it takes to verify that a nominal voltage is present.