Sign in with
Sign up | Sign in
Your question

Computer not turning on

Last response: in Components
Share
December 25, 2011 2:52:45 AM

I have an old HP Pavilion a1600n that I'm repairing to run some tests on. This PC was from an friend that moved. When I turn it on, nothing appears on the screen, and the monitor is not faulty. I have tried another video card, but still no video. All fans and lights light up. I'm suspecting an power supply issue but would like to have that confirmed before I spend 100 dollars on it. Thank you for any help!

More about : computer turning

December 25, 2011 3:47:22 AM

is there both an onboard and gfx card, try both, is there a buzzer/beeper, does it beep?
December 25, 2011 4:48:53 AM

strip it down to bare minimum. CPU/Ram/video. If more than 1 stick of ram. Then make it only 1 stick.
If that doesnt work. Try moving the Ram to a different slot. Or try the other stick, if there was one.

Then if the CPU-fan is connected directly to motherboard, does it spin when you turn it on?

Then more on what the other guy said. If it has onboard video, use that. If it works, go into bios. Then disable the onboard video. Or make the agp/pci-e/pci video card as primary. I dont know what type of video card, you have. So i listed 3 types.
December 25, 2011 11:05:53 AM

no video can also be caused by faulty cpu
December 26, 2011 3:22:30 PM

keha12 said:
strip it down to bare minimum. CPU/Ram/video. If more than 1 stick of ram. Then make it only 1 stick.
If that doesnt work. Try moving the Ram to a different slot. Or try the other stick, if there was one.

Then if the CPU-fan is connected directly to motherboard, does it spin when you turn it on?

Then more on what the other guy said. If it has onboard video, use that. If it works, go into bios. Then disable the onboard video. Or make the agp/pci-e/pci video card as primary. I dont know what type of video card, you have. So i listed 3 types.


Thanks for the reply! So I took it down to 1 stick of ram, CPU, HDD, dvd. 2/2 fans spin, and there is no video at all, much less bios. There is only the onboard video and I have tried putting in an spare graphics card. BTW: I'm good at software but suck at hardware... know the parts but dont know how to wire it, so I'm not even sure the hard drive/ dvd is wired correctly. But if they were not correctly hooked up, the bios should still come up. Once again, thanks for the help.
December 26, 2011 3:24:49 PM

nna2 said:
is there both an onboard and gfx card, try both, is there a buzzer/beeper, does it beep?


As I wrote earlier (to keha12), there is just onboard. I have tried a PCI graphics card with no luck. There is no beep, or buzz. The computer just starts up and keeps running with nothing comming up. **An import point I forgot... when I got this PC to fix up, there coins in it... could the coins short out the motherboard or something?
Thanks for the replies.
December 26, 2011 3:25:46 PM

mcnumpty23 said:
no video can also be caused by faulty cpu


Does that only apply to PCI/PCI Express video?

Thanks for replying.
December 26, 2011 3:26:39 PM

no--if your cpu is faulty you get no video period
December 26, 2011 3:34:35 PM

mcnumpty23 said:
no--if your cpu is faulty you get no video period


Wow.... that was fast...
so is there any way to check if the CPU is faulty other than to replace it?
December 26, 2011 3:52:05 PM

not really unless you or a friend have another pc with a compatible motherboard to test it in
December 26, 2011 4:04:16 PM

mcnumpty23 said:
not really unless you or a friend have another pc with a compatible motherboard to test it in


I probably have one... might, so it just has to have the same socket, right?
December 26, 2011 4:17:11 PM

yes--same socket and be able to support the cpu speed

think it may be a A8M2N-LA motherboard in there so socket am2--AMD Athlon 64, Athlon 64 X2, and Sempron processors

though not 100% sure as they may have used different boards for some of that model

motherboard model should be written on the board--though hp may have renamed it to something like Nodus-GL8E
December 26, 2011 4:23:52 PM

mcnumpty23 said:
yes--same socket and be able to support the cpu speed

think it may be a A8M2N-LA motherboard in there so socket am2--AMD Athlon 64, Athlon 64 X2, and Sempron processors

though not 100% sure as they may have used different boards for some of that model

motherboard model should be written on the board--though hp may have renamed it to something like Nodus-GL8E



Ok, from what you have told me, it could be a power supply and/or a processor problem. I have a power supply that has sat in the rain, but would like to try that first. What are the steps in changing the power supply?

Also, why is this in the UK fourms? I'm in the United States.....
December 26, 2011 4:34:32 PM

didnt realise there were seperate forums for seperate countries

the questions i answer seem to come from all over even though i am in the uk

not sure i would be happy using a psu that had been out in the rain

changing the psu is straight forward just look at the one thats in there--you dont even actually have to take the old one out of the case


disconnect it from mains power--press on /off switch to discharge capacitors

just disconnect the cables leaving the old one----connect the same type of cables to the same places the old ones were

sit the new psu outside the case--connect power and turn on

you can totally remove the old one if you want and put the new one inside the case but if it doesnt fix the problem then you will have to take it back out and put the other one back in so its just quicker the way i said
December 27, 2011 3:57:46 AM

mcnumpty23 said:
didnt realise there were seperate forums for seperate countries

the questions i answer seem to come from all over even though i am in the uk

not sure i would be happy using a psu that had been out in the rain

changing the psu is straight forward just look at the one thats in there--you dont even actually have to take the old one out of the case


disconnect it from mains power--press on /off switch to discharge capacitors

just disconnect the cables leaving the old one----connect the same type of cables to the same places the old ones were

sit the new psu outside the case--connect power and turn on

you can totally remove the old one if you want and put the new one inside the case but if it doesnt fix the problem then you will have to take it back out and put the other one back in so its just quicker the way i said


Ok... I'll try that, Ill post back tomorrow...

btw: while I may be a geek software wise, I fail at hardware maintenance...
December 28, 2011 5:15:43 PM

mcnumpty23 said:
didnt realise there were seperate forums for seperate countries

the questions i answer seem to come from all over even though i am in the uk

not sure i would be happy using a psu that had been out in the rain

changing the psu is straight forward just look at the one thats in there--you dont even actually have to take the old one out of the case


disconnect it from mains power--press on /off switch to discharge capacitors

just disconnect the cables leaving the old one----connect the same type of cables to the same places the old ones were

sit the new psu outside the case--connect power and turn on

you can totally remove the old one if you want and put the new one inside the case but if it doesnt fix the problem then you will have to take it back out and put the other one back in so its just quicker the way i said


mcnumpty23,

I have taken a look at the psu, but the wires go inside... Do I have to take apart the psu to remove the connectors? and if so, how?

Thanks,
sam
December 28, 2011 5:21:59 PM

no--you remove the ends that are connected to the motherboard and hard drives and other components not inside the psu

heres a youtube showing it

plenty more on youtube if this ones not clear enough--just search replace pc psu

http://www.youtube.com/watch?v=UzolRkN7Eew

though he totally removes the psu--where i would just leave it in and test with the other psu outside the case for speed

December 29, 2011 3:17:46 AM

mcnumpty23 said:
no--you remove the ends that are connected to the motherboard and hard drives and other components not inside the psu

heres a youtube showing it

plenty more on youtube if this ones not clear enough--just search replace pc psu

http://www.youtube.com/watch?v=UzolRkN7Eew

though he totally removes the psu--where i would just leave it in and test with the other psu outside the case for speed


Ok, before I do so, take a look at these pictures. The PSU I'm using as the replacement is one from a eMachine. There is no power indication light, which leads me to want you to take a second look. The "broken" PSU are the pictures titled "hp 1" all the way to 6, the one thats going to be the replacement are titled "emachine 1" and 2. Please take a look and tell me what you think.

here's the link!

Thanks,
Sam
December 29, 2011 8:03:16 AM

looks like the emachine psu should do--cant see the wattage but the hps only 300w so should be ok

not all psu have a power light or on off switch on them--doesnt really matter--just connect the mains cable last--the psu shouldnt come on anyway till you press the power button on the pc

youll know the psu is on as the fans will spin--leave the case open when you power it up so you can check fans are spinning
December 29, 2011 1:43:37 PM

Lets do this systematically. First, this is a "build your own" thread, but it will show you how things go together:
Build it yourself:
http://www.tomshardware.co.uk/forum/274745-13-step-step...

Having spare components to test with is very useful - if they are known good parts.
Next , 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 not, 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:

Check for line power at the PSU input. Extension cords, power strips, and power cords do fail.

If you have power and no beeps, suspect components in likely order are PSU, motherboard, and CPU.

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: 5 volts always on. 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.
January 9, 2012 1:02:02 AM

jsc said:
Lets do this systematically. First, this is a "build your own" thread, but it will show you how things go together:
Build it yourself:
http://www.tomshardware.co.uk/forum/274745-13-step-step...

Having spare components to test with is very useful - if they are known good parts.
Next , 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 not, 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:

Check for line power at the PSU input. Extension cords, power strips, and power cords do fail.

If you have power and no beeps, suspect components in likely order are PSU, motherboard, and CPU.

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: 5 volts always on. 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.


Thanks for the help!

I've tested the power supply according to this video; http://www.youtube.com/watch?v=EpmsYrDRcG0 , and the voltages match the ones on http://en.wikipedia.org/wiki/Power_supply_unit_(computer) scroll down to the "wiring diagram".... and I have tested the power switch by doing the "short the two pins" thing. I'm pretty sure it's a failing processor now...

Sam
January 10, 2012 12:20:12 AM



Can someone please confirm the fact it's a failing processor?

Thanks!
March 26, 2012 12:17:00 AM


Hello, once again!

I know this forum is quite old, but I have gotten around to working on this computer. The PSU has been tested and verified working. I have put in a new processor I got in the mail. The computer still does not work. I've given up alotta hope now, is there anything else that could be wrong? It's possible I could have not grounded my self prior to touching the CPU, but that seems unlikely. Please help!


-Sam

jsc said:
Lets do this systematically. First, this is a "build your own" thread, but it will show you how things go together:
Build it yourself:
http://www.tomshardware.co.uk/forum/274745-13-step-step...

Having spare components to test with is very useful - if they are known good parts.
Next , 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 not, 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:

Check for line power at the PSU input. Extension cords, power strips, and power cords do fail.

If you have power and no beeps, suspect components in likely order are PSU, motherboard, and CPU.

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: 5 volts always on. 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.

!