Question Mobo appears dead after using Dust-Off. Suggestions on troubleshooting?

suntower

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The inside of my PC was very dusty. I sprayed Dust-Off on the inside and when I went to re-start it doesn't POST. The fans work, the drives spin up and the mobo lights come on but no beeps and all lights on keyboard are stuck on.

Is this thing 'dead' or is the a process for troubleshooting?

Intel Sandybridge 2600
ASUS P8Z68LVX LGA1155 mobo
Samsung 240gb SSD boot drive
Antec 500w PSU
Antec Midtower case
Windows 10 Pro
 
It's likely a static issue. My suggestion is to remove all RAM sticks and re-seat them (with the power cord out) then plug it in and re-start. Blowing out the PC can cause a static charge to accumulate which this process should clear.
 

suntower

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It's likely a static issue. My suggestion is to remove all RAM sticks and re-seat them (with the power cord out) then plug it in and re-start. Blowing out the PC can cause a static charge to accumulate which this process should clear.
I should've been more specific in my o/p. Here's what happens:

1. Hit power switch. PSU fan and CPU fan come on along with mobo lights and drives.

2. After about 3 seconds, everything except the mobo lights die. Then wait 2 seconds and then...

3. PSU fan and CPU fan come back on along with drives.

But again, no beeps, the keyboard lights are stuck on.

Are you still suggesting RAM?
 
The board should beep without memory but it needs an onboard buzzer for this - many newer boards don't include one. At any rate, does the same reboot loop still happen with no RAM? Next step, reset BIOS battery (again, unplugged from power, locate small coin cell battery and gently press retention clip to release it. Leave out for a minute before restarting. If nothing works, remove EVERYTHING (except power cables and power button cable), reseat CPU, etc. Pull board from case to test out of case.

If nothing works after all this, determine warranty status with ASUS.
 

suntower

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The board should beep without memory but it needs an onboard buzzer for this - many newer boards don't include one. At any rate, does the same reboot loop still happen with no RAM? Next step, reset BIOS battery (again, unplugged from power, locate small coin cell battery and gently press retention clip to release it. Leave out for a minute before restarting. If nothing works, remove EVERYTHING (except power cables and power button cable), reseat CPU, etc. Pull board from case to test out of case.

If nothing works after all this, determine warranty status with ASUS.
Will do. Question: The mobo seems to be covered in dust that is somewhat 'oily'. Or rather caked on. I'm wondering if this couldn't be causing a short/open circuit somehow. Is there some (safe) way to clean the mobo or should I not worry about this?

(I'm a bit leery after the Dust-Off) but it just seems odd that the whole thing should stop working out of the blue. I mean there must be -something- that is causing a short/open.

Suggestion?

THANKS!
 
Hmm, probably just gently wiping it off would seem the safest option. Oil itself won't short anything out: it's non-conductive. Occasionally you hear of a whole system submerged in a mineral oil tank as a means of cooling.
 

suntower

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Hmm, probably just gently wiping it off would seem the safest option. Oil itself won't short anything out: it's non-conductive. Occasionally you hear of a whole system submerged in a mineral oil tank as a means of cooling.
OK, I removed battery as you advised and both RAM sticks and re-tried. Same thing:

1, PSU fan comes on. CPU fan comes on. Lights come on. Drives come on.

2, after about 2 seconds, CPU fan shuts down and drives shut down, but PSU fan and lights stay on.

3. About 1 second delay, then everything comes up but NO beeps. (The board -does- have a built in 'beeper'.)

I will remove the mobo from case later tonight or tomorrow AM and report back.

Thanks.

PS: I have never sent in a mobo for repair/replace... I've always just replaced. How long does that process generally take?
 

4745454b

Titan
Moderator
I doubt he's going to get a cross ship. We are talking about a Z68 board here. Everything here is pretty old.

One danger with using a can like that is condensation. If the can is tilted you can get water vapor. It can spray out the nozzle. Depending on where it lands the board could be dead. I would double check your connections to make sure everything is tight, but you're probably better off just buying a used board. Due to the age of the parts I don't see asus being able to help you.
 

suntower

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I (finally) replaced the mobo with an ASUS P8Z77-VLK from Newegg. When I power on,
  1. The green light on the mobo lights
  2. The case fan spins for 5 seconds then stops
But the CPU fan does not spin and there is no speaker beep.

I am fairly sure I was careful in building it, but who knows?

Where to begin in troubleshooting?

FWIW, this is perhaps the 10th PC I've built in the past decade and this is the first I've had with these types of problems. Perhaps it's simply my turn.
 

Karadjgne

Titan
Herald
Not a stupid question at all.

Pull the pc apart on a table covered with cardboard. All you'll need is 1 stick of ram, the cpu/cpu cooler, motherboard and psu and monitor. That's all. No other components or case.

Put the ram in slot #2, mount cpu/cooler, plug in the 2x power sockets to the mobo and using a small flat screwdriver (you'll need to look on mobo for directly where the pwr_on button pins are) gently touch both pwr pins. (if the power button will reach, use that).

This is called bread-boarding (just is, no idea where it got the name).

You should go through post and get either into bios or the inevitable warning that there's no OS drive.

If you don't, power down and swap the ram either with another stick, or into a different socket.

If it does boot, and remain booted, then the issue is not with the psu or ram or motherboard, but with one of the other components not yet mounted. Start with fully adding ram back. Then gpu, then storage.

If you get everything working outside the case, the issue is with the case. Check every single wire that's connected. Look for anything discolored or burnt or stripped/broken. Check the case thoroughly for any marks where wires went through or past metal. It's possible that during cleaning you pinched or shorted something, especially near any hdd cages.

Breadboarding starts with absolute minimums, building up until something fails. Takes a decent amount of time, (or can) or you might find the issue right off. If you can't post with just 1 stick of ram, there's only 3 possible components it could be. Mobo, psu, ram. You replaced the mobo, same symptoms, so it's either the ram or the psu. Borrow a stick from a friend, one you know is working. If it still doesn't post. It's the psu.

Once you eliminate the improbable, whatever left, no matter how impossible, has to be the answer.
 

suntower

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Not a stupid question at all.

Pull the pc apart on a table covered with cardboard. All you'll need is 1 stick of ram, the cpu/cpu cooler, motherboard and psu and monitor. That's all. No other components or case.

Put the ram in slot #2, mount cpu/cooler, plug in the 2x power sockets to the mobo and using a small flat screwdriver (you'll need to look on mobo for directly where the pwr_on button pins are) gently touch both pwr pins. (if the power button will reach, use that).

This is called bread-boarding (just is, no idea where it got the name).

You should go through post and get either into bios or the inevitable warning that there's no OS drive.

If you don't, power down and swap the ram either with another stick, or into a different socket.

If it does boot, and remain booted, then the issue is not with the psu or ram or motherboard, but with one of the other components not yet mounted. Start with fully adding ram back. Then gpu, then storage.

If you get everything working outside the case, the issue is with the case. Check every single wire that's connected. Look for anything discolored or burnt or stripped/broken. Check the case thoroughly for any marks where wires went through or past metal. It's possible that during cleaning you pinched or shorted something, especially near any hdd cages.

Breadboarding starts with absolute minimums, building up until something fails. Takes a decent amount of time, (or can) or you might find the issue right off. If you can't post with just 1 stick of ram, there's only 3 possible components it could be. Mobo, psu, ram. You replaced the mobo, same symptoms, so it's either the ram or the psu. Borrow a stick from a friend, one you know is working. If it still doesn't post. It's the psu.

Once you eliminate the improbable, whatever left, no matter how impossible, has to be the answer.
Good advice. However, that assumes that I have a good PSU. Karadjgne is proposing that my PSU might be bad. Is there a way to test for that without a 2nd PSU?

TIA.
 

Karadjgne

Titan
Herald
No. You can buy (or borrow) voltage checkers that'll look for the right voltages from the psu, but they are a fallacy. There's a huge difference between a rail totally failing and one that works at idle and fails under loads. Your psu works at startup, the fans spin, lights come on etc. It's not until there's an actual load during post where things get funky and you are restarted.

Unfortunately part of the time it's the psu causing this, part of the time it's bad ram and part of the time it's the mobo. You changed mobo's and got no fix, so it's down to ram or psu. That's at a minimum. And that's where you need to start, eliminate any other potential causes. No storage, no gpu, no fans other than cpu cooler, no nothing but ram, cpu, mobo and psu. If the symptoms persist, your other stuff is good by default, if they go away then anything you didn't include is the culprit.

This is the way better computer repair shops do things, that way they don't spend unnecessary resources replacing things that dont need replacing.
 

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