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Monitor Says No Signal

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January 1, 2012 5:29:25 AM

Hello Techies :hello: 

I gave my little sis my old computer, worked fine when it left here but she lives 4 hours away. When she got home her husband hooked all of it up and monitor says :pfff:  No Signal. I had it all running coulple days before it left here , reformatted and clean install of Windows and such, using the same monitor and everything that went with it. So did something shake loose, did the vibration in the car ruin the video card/mobo/PSU I don't know? Where to begin with the troubleshoot? I had him check and recheck the cables, try both inputs on the video card, and try the on board video to no avail.

The Specs I posted on an earlyer thread here. I never did upgrade it so the specs are the same.

http://www.tomshardware.com/forum/forum2.php?config=tom...


Thanks in advance ;) 

More about : monitor signal

a b B Homebuilt system
a c 76 U Graphics card
a b C Monitor
January 1, 2012 5:50:03 AM

is he sure it is actually turning on? harddrive light flashing away as it boots, fans running, etc. if so:

Has he tried switching the input selection on the monitor? I know mine will auto switch, but maybe yours doesn't and is on the wrong input?

if they have another monitor (or TV with inputs) have them try that, or have them try the monitor on another PC to make sure its OK.

finally I would have him pull the GPU which will force it to use the onboard GPU. if the onboard works reinstall the discrete one and try using it again.
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January 1, 2012 8:14:53 PM

Well tried another monitor, unhooked the video card to force the onboard video, tried both monitor and a Tv, checked all connecrtions on the MoBo. Nothing. He said fans are all spinning but the DVD/RW and DVD drive bays won't open and no the lights aren't blinking so I'm thinking chunked MoBo?

Edit: He said the hard drives were all spinning up too.

Edit: Also tried switching out the ram sticks and using one at a time in both slots
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a b B Homebuilt system
a c 76 U Graphics card
a b C Monitor
January 2, 2012 1:54:46 AM

I would expect DVD drives to open as long as there is power. so that's odd. does the motherboard give the startup beep, or any other beep?

I would say reset the BIOS. if that doesn't work disconnect everything. cards, drives, just onboard video, ram and CPU. check all the motherboarx screws. if you get nothing there, and he doesn't have another PSU to try, reseated the CPU incase the heatsink pulled it off a bit while driving.
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January 2, 2012 2:27:50 AM

unksol said:
I would expect DVD drives to open as long as there is power. so that's odd. does the motherboard give the startup beep, or any other beep?

I would say reset the BIOS. if that doesn't work disconnect everything. cards, drives, just onboard video, ram and CPU. check all the motherboarx screws. if you get nothing there, and he doesn't have another PSU to try, reseated the CPU incase the heatsink pulled it off a bit while driving.



Reset bios you mean like reseting cmos by removing the battery for a few seconds and putting it back in? that battery has never been changed by the way, that couldn't have anything to do with it would it?
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a c 122 B Homebuilt system
a b U Graphics card
a b C Monitor
January 2, 2012 4:15:54 AM

Work systematically through our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-postin...
I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

If no luck, continue.

The following is an expansion of my troubleshooting tips in the breadboarding link in the "Cannot boot" thread.

I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different, but they all use a single short beep for a successful POST.

Breadboard - that will help isolate any kind of case problem you might have.
http://www.tomshardware.com/forum/262730-31-breadboardi...

Breadboard with just motherboard, CPU & HSF, case speaker, and PSU.

Make sure you plug the CPU power cable in. The system will not boot without it.

I always breadboard a new build. It takes only a few minutes, and you know you are putting good parts in the case once you are finished.

You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU. Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

If no beeps:
Running fans and drives and motherboard LED's do not necessarily indicate a good PSU. In the absence of a single short beep, they also do not indicate that the system is booting.

At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire (standby power supply): 5 volts always on. The green wire should also have 5 volts on it. It should go to 0 volts when you press the case power button (this is also a good way to test the power switch and the associated wiring), then back to 5 volts when you release the case power switch. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=yout...

A way that might be easier is to use the main power plug. Working from the back of the plug where the wires come out, use a bare paperclip to short between the green wire and one of the neighboring black wires. That will do the same thing with an installed PSU. It is also an easy way to bypass a questionable case power switch.

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.

If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card.

Silence, long single beeps, or series of short beeps indicate a problem with the memory. If you get short beeps verify that the memory is in the appropriate motherboard slots.

Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.
At this point, if the system doesn't work, it's either the video card or an inadequate PSU. Or rarely - the motherboard's PCIe interface.

Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.
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