Video card or PSU

[shadowbreaker513]

I got my new hard drive in today, so I figured I may as well do some work on my computer while it was inside anyway. I notice I still had my old 520 modstream laying around, and decided to do some work on it. Previously I had to remove it, as my computer would turn on and POST but nothing would display on the screen (LED codes on the motherboard let me know it booted successfully). Took it to a shop that had parts to diagnose the problem, and they said it was the PSU. I had to mod the 4 pin connector on the PSU previously as it was too short, so I chalked it up to this finally failing, and installed my old 480w Thermaltake.

On a hunch, I unwrapped the tape on the modstream and found out, sure enough, 1 of the connections had come undone, I reconnected and rewrapped all of the cables. Put the motherboard on a piece of cardboard (was also transferring cases), plugged in the video card, RAM, PSU, and started it. Same problem as before. Fiddled with a few connections, thing stopped booting alltogether. Oh well, I figured, so I went to reconnect the old PSU. Started it up with the TT, and a loud screaming was coming from the PSU. I noticed I forgot to plug in my video card. Turned it off, plugged it in, and booted it. Uh-oh, same problem with the other PSU. Now that this problem has spread to 2 PSUs, I'm wondering if it isn't the video card failing

I've noticed some odd things the past few days. Twice after coming back to my computer after it being idle long enough for the screensaver to turn off, It refused to come out of sleep. I would mash the keyboard, jiggle the mouse, but it stayed with the fans whirling, but the monitor off and the light just blinking. Also while playing left4dead, mid game the computer just straight up turned off, like I had accidentally hit the power switch.

Anyway, TLDR, previous PSU problems, now happening on 2 PSUs, strange problems the past few days, POSTs but no output. No idea what's wrong.

Anyone have any ideas?

 

[Dangman]

Try a 3rd PSU? Third time is the charm

Oh and try these:

If your system doesn't POST...

This is basic troubleshooting if your system has never POSTed (as in, you just put it together); Though, it may be helpful to others whose system no longer POSTs...

If you have both the 20/24 pin main ATX connector plugged in, AND the 4-Pin (or 8-pin) ATX12V P4 CPU connector plugged in, then the board should boot fine (unless it requires more power connectors from the PSU). First, try clearing the CMOS w/ the proper jumper or button.

The next thing you could do is test the PSU. Jump start it (on the main atx connector, short the green wire with any black wire, using a paperclip), and see if it stays on. If not, then its probably a faulty PSU. If it works then you can proceed with the suggestions below. ***NOTE: The paperclip trick is a simple test for those that do not have PSU testers, multimeters, nor a spare PSU to test with. It is not a 100% conclusive test of the PSU.

How to test with a multimeter @ BFG

Setup everything outside of the case, with the mobo on top of its cardboard box. Plug in only the essentials:
- PSU (namely: main 20/24-pin ATX connector and 4-pin ATX12V P4 CPU Connector; The 4-pin should work in the 8-pin EPS12v plugs, too)
- CPU w/ HSF
- Single stick of ram
- Videocard if there is no onboard video (along with its power connector, if it has one)
- System speaker/buzzer (your board may have an on-board tweeter/buzzer/speaker)
- Monitor & Keyboard

Reset/Clear the CMOS by following the instructions in your mobo manual.

* Use a screwdriver if your board doesnt have an onboard power switch. Jump the two power switch leads to turn the power on.

If it won't post, try different RAM slots. If it still won't post, pull out the ram (so no ram in the system) and listen for error beeps. If none, pull the vidcard and listen for error beeps. If none, re-seat the CPU and HSF, then try again. Report back with results if you're still having issues.

 

[shadowbreaker513]

Was digging around and found that I had a 7950GT never used in a system sitting in a box, and an old 420w mini aspire PSU. Swapped both of those in, and took out all the ram but 1 stick. Same problem. Tried a different stick of RAM, no change. Is it possible the CPU fried itself? While fiddling around last night I noticed on one of the boots that a cable was laying on the heatsink fan, preventing it from starting. I moved it, it twitched twice, and then started up. Is it possible, or even likely that the internal throttling/shutdown mechanism failed and the CPU fried itself in the few seconds the fan was off?

I also noticed that my motherboard isn't particularly useful at telling me what's wrong. It uses an LCD screen instead of error beeps, and the screen doesn't seem to be functioning. It goes quickly through most of the codes and then stops on FF. FF is labeled as boot, and is supposed to indicate a sucessful boot.

 

[shadowbreaker513]

Curious as to if this was a monitor problem, I plugged in my TV to my computer. All I got was a no signal message. The TV was set up correctly as I was immediately able to plug it into my laptop and get a signal. So apparently in a computer with a processor and motherboard working fine yesterday, with the only problem I've ever had being poor onboard sound, I'm getting the same problem I got a year ago due to a faulty PSU after testing with 4 sticks of ram, 2 video cards, and 3 power supplies. I'm stumped.