System broke. No signal to monitor. Help!

[trale]

I have an older model Shuttle XPC system (it uses socket 939). It just stopped working suddenly. The screen froze. So I had to power down, then power back up the system.

The fan spins back up, the hard drive lites up, and everything ~sounds~ normal. But my LCD monitor remains blank! It does not detect a signal from my system. It's hooked up with DVI connection.

I hooked up my LCD to a laptop, and it works fine. So my LCD is not an issue.

My system also has a regular VGI connector, so I tried that too. No luck.

My system is screwed and I can't even go through my usual trouble shooting steps since I can't see jack. No P.O.S.T screen, no nothing. My LCD simply says "no signal detected".

Please help me trouble shoot this. What can cause the signal from the system to the monitor to suddenly not work? Could my CPU be fried? Or RAM? What components are suspect here?

Thanks in advance!

[Phage]

Videocard ?

[peterb]

As the man says - graphics card. You could try removing the card and restarting - if you get some beeps it will indicate that the system is reaching POST, and that will be reasonably conclusive.

Other possibilities are PSU or a memory problem.

You might want to reset the bios configuration settings by claering the CMOS memory, just in case that has become corrupted.

I am assuming that the mobo doesn't have onboard graphics, if it does, then it may boot normally without the video card - otherwise you will need to try the card in another machine, or get a (cheap) replacement card to see if that corrects the fault.

[Zhaoman]

i have the same problem, been using my laptop for the last few weeks, havent gotten round to looking at it yet.

from ur description it could be one of four things: psu, cpu, mobo or gpu.

it's probably not the psu since everything seems to power up fine, it's unlikely to be the gpu since the screen froze which suggests the gpu was still able to communicate with the monitor and most serious gpu errors would still give a screen full of colours. that leaves the cpu and mobo, and tbh a straight out blank screen with nothing else would suggest that one of them is dead. i'll be going on holiday next week so i cant look into my own comp but im thinking most likely dead cpu... check out the ram first though if u have two sticks then it's unlikely that both will blow at the same time. but u never know. keep us posted coz this might shed some light on my rig :S

[Flash477]

I had this problem with my PC and it was caused by a memory slot on the m/b dying - swapped memory to a different slot and has worked fine ever since

[trale]

I'm hoping this is a PSU or RAM problem.

If it's a graphics card problem, then I'm going to have to replace my mobo - as this is a Shuttle SFF system with integrated graphics.

I'll try to swap out the RAM and see what gives.

[trale]

So here's an update:

- Removed my tv tuner card, DVD drive, and one 1 stick of RAM = System boots back up. Yay!!!

- Put back the other stick of RAM = random results on several tries.
- Boots but freezes
- no boot (no signal to monitor)

- Take out same stick of RAM, but plug DVD drive back in = system functioning normal. Yay.

So it ~seems~ that I have a bad stick of RAM. However, this isn't conclusive, because I haven't tried to swap out the good stick with the supposedly bad stick yet.

But I am making progress! (And at least my system works, even though my RAM is now halved)

[Zhaoman]

yeah it sounds like ram alright. phew lol. at least it isn't the cpu or mobo. bad ram would usually give random freezes and stuff, must be completely dead ram if it gives black screen but that's quite unlikely. count urself both unlucky and very lucky

[trale]

So I went back in and did some comprehensive RAM testing (using Memtest 86), and jotted down the results. Here are the results. Note that I have 2 RAM slots, which I'll call Slot 1 and Slot 2, and I'll call my Ram sticks "ramA" (the one that's already in Slot 1 before I started these Memtests) and "ramB" (the allegedly bad one I took out at the end of my previous post).


Test 1: Removed both sticks, then put ramB in slot 1.
Results: No errors. Odd, so it seems the allegedly bad ram isn't bad after all.

Test 2: Remove, then put ramA in slot 1.
Results: No errors. OK, so both sticks seem to be good by themselves.

Test 3: Put ramA in slot1 and ramB in slot2.
Results: Memtest froze midway! Then when I force a reboot, there's no signal to LCD again!

Test4: Switch them up. ramB in slot1 and ramA in slot2
Results: LCD works again, boot to memtest ok, but froze at 62%. When I reboot after the freeze, again no signal monitor.

Notes so far: So it seems that both of sticks together is causing the problem, and very consistently! My next test will be to test to see if my DIMM slot2 itself is the culprit.

Test5: Remove both sticks. Put ramB in slot 2
Results: Memtest ran. Errors reported at around 20% of test! (ECC correctable error). And then it reboots itself then the test is about 60% done. But when it reboots, no signal to monitor again.

Test6: Remove stick. Put ramA in slot 2
Result: Memtest ran, then suddenly screen goes crazy with colors midway. need to reboot again.


In the end, I went back to working with one stick of ram (RamB in Slot1), and I'll run my system like this for a while to see if anything develops. But my system ~seems~ to work fine so far, but with 1/2 the RAM.

So all in all, it seems the DIMM slot 2 itself is the culprit! (ie mobo is bad). Is this a fair conclusion? Can anyone think of anything else?

[trale]

To add to my last post, ideally I would like buy a new pair of RAM sticks (DDR1, 400 MHZ, 2 GB total) and run Memtest again, but really is there any point? It seems the slot itself is screwed.

[Zhaoman]

yeah its fair to assume the slot is the culprit. u really don't need to try new sticks because both sticks ran fine on the other slot.

[UseItNow]

Hope you get your problem sorted soon, it seems I've possibly got a similar situation to yourself, will have to post later for help from folks. I just hope my hard drive isn't gone! I never backed up anything on it, got lazy and complacent!