Computer Geeks- Help needed
#1
Registered User
Thread Starter
Computer Geeks- Help needed
I picked up a dell 1721 inspiron laptop from the original owner a cop
Here is the story i got -- he was sitting in a chair using it plugged in and his buddy tripped on the chord and the screen went black and then it would not boot back up. He then took it to a local computer shop that looked at it and said the hard drive was ok and checked the CPU claimed it was as well and then came to the conclusion that the power port (plug in connector on the motherboard was bad.
They said it had a broken pin in it and it would need a motherboard or someone to install a new power port which they would not due because they could not warranty it. Charged him $60 for this opinion and then offered to buy it from him cheap.
I did not think this sounded right and i asked him if it would boot from the battery and he said no. He went out and bought a new laptop and sold me this one.
I have checked out the power supply and it will charge the battery and will power it without the battery installed i have the proper 19.5vdc to threw the port (connector) and onto the bottom of the M board also the center tap from the oem power supply appears to work as it charges up and shuts off the blinking blue light.
When you try to boot from either power source it try's to start for about 2 seconds the hd starts up but the cooling fan does not even try also no beeps and it then shuts down/powers off. I have tryed this from many configurations for example without the HD or the optical drive installed and each ddr stick in different slots as well as each one separate.
Does anybody know if this unit has a fail safe in it that must see the fan run in order to boot up ?
I have checked the fan at the male 3 pin plug when not hooked to the board and get the following results.
Black to red = 543 ohms
black to yellow = 651 ohms
Red to yellow = open
Any idea which two are the 5vdc needed to run the fan to test it ?
I am thinking at this point the motherboard has a problem.
Could be a nice unit fixed it is very clean has a 17" screen and even came with a wireless remote but dell is totally useless once you are out of warranty no info on their website and they won't even talk with you other than to get you to buy another year of warranty for $206
Idea's thoughts and suggestions please ...............
Here is the story i got -- he was sitting in a chair using it plugged in and his buddy tripped on the chord and the screen went black and then it would not boot back up. He then took it to a local computer shop that looked at it and said the hard drive was ok and checked the CPU claimed it was as well and then came to the conclusion that the power port (plug in connector on the motherboard was bad.
They said it had a broken pin in it and it would need a motherboard or someone to install a new power port which they would not due because they could not warranty it. Charged him $60 for this opinion and then offered to buy it from him cheap.
I did not think this sounded right and i asked him if it would boot from the battery and he said no. He went out and bought a new laptop and sold me this one.
I have checked out the power supply and it will charge the battery and will power it without the battery installed i have the proper 19.5vdc to threw the port (connector) and onto the bottom of the M board also the center tap from the oem power supply appears to work as it charges up and shuts off the blinking blue light.
When you try to boot from either power source it try's to start for about 2 seconds the hd starts up but the cooling fan does not even try also no beeps and it then shuts down/powers off. I have tryed this from many configurations for example without the HD or the optical drive installed and each ddr stick in different slots as well as each one separate.
Does anybody know if this unit has a fail safe in it that must see the fan run in order to boot up ?
I have checked the fan at the male 3 pin plug when not hooked to the board and get the following results.
Black to red = 543 ohms
black to yellow = 651 ohms
Red to yellow = open
Any idea which two are the 5vdc needed to run the fan to test it ?
I am thinking at this point the motherboard has a problem.
Could be a nice unit fixed it is very clean has a 17" screen and even came with a wireless remote but dell is totally useless once you are out of warranty no info on their website and they won't even talk with you other than to get you to buy another year of warranty for $206
Idea's thoughts and suggestions please ...............
#2
With age comes the cage
Sounds like the mother board to me, it is not uncommon for them to break at this connection. mine did the same thing(under normal usage) 4 days before the 4 yr warranty expired..
Power cord connections need to be in a recessed strain relieved enclosure but they are not. The hard drive can be pulled and your data salvaged of of it.
Power cord connections need to be in a recessed strain relieved enclosure but they are not. The hard drive can be pulled and your data salvaged of of it.
#3
Registered User
Thread Starter
Sounds like the mother board to me, it is not uncommon for them to break at this connection. mine did the same thing(under normal usage) 4 days before the 4 yr warranty expired..
Power cord connections need to be in a recessed strain relieved enclosure but they are not. The hard drive can be pulled and your data salvaged of of it.
Power cord connections need to be in a recessed strain relieved enclosure but they are not. The hard drive can be pulled and your data salvaged of of it.
I have checked for power threw that connector and it is getting to the board at that point and i have re soldered that connection as well to make sure their are no issues at that point.
Also i do not see any damage to the board or broken trace on it. The plug makes a decent connection as well. Nothing appears to be broken in the plastic or the metal pins in that connector. The guy claimed it never fell on the floor and that appears to be true it still looks new.
I had even bought a new connector for the board before i had a chance to take it apart and check it myself and trusting their prior diagnosis !
Thought it was going to be be a real easy cheap fix
I can sell just the screen and memory to cover my investment but i would like to fix it if i can reasonably. This thing was $1300 or more new less than 2.5 years ago.
#4
It sounds like it could be a couple things ....
- The cooling fan is shot and/or the motherboard controls for it are shot,
- Cooling fan/heatsink isn't in contact with the CPU,
- Bad thermal sensor (aka bad motherboard)
Thermal shutdown is normal and would happen under 90 seconds if the CPU gets too hot, and once that tempurature threshold is reached the circuit trips the main power and it shuts down until its cool enough to power back up.
Remove the thermal compound from the contact patch between the CPU and heatsink, then replace it with some Arctic Silver 5 and reassemble. Use denatured alcohol and a soft lint free cloth to remove the old thermal compound and residue before applying the new compound, which should be roughly half the size of a pea.
Make sure the heatsink/heatsink mounts aren't broken, as this would also cause the thermal shutdown issues I believe you're having.
If Dell wants only $206 bucks for the warranty, make sure it will cover the repairs and buy it. The screens are worth anywhere from $500 to $1100 to the right person, and for $200 bucks I would do it so that its covered for anything else that might happen.
Kris
- The cooling fan is shot and/or the motherboard controls for it are shot,
- Cooling fan/heatsink isn't in contact with the CPU,
- Bad thermal sensor (aka bad motherboard)
Thermal shutdown is normal and would happen under 90 seconds if the CPU gets too hot, and once that tempurature threshold is reached the circuit trips the main power and it shuts down until its cool enough to power back up.
Remove the thermal compound from the contact patch between the CPU and heatsink, then replace it with some Arctic Silver 5 and reassemble. Use denatured alcohol and a soft lint free cloth to remove the old thermal compound and residue before applying the new compound, which should be roughly half the size of a pea.
Make sure the heatsink/heatsink mounts aren't broken, as this would also cause the thermal shutdown issues I believe you're having.
If Dell wants only $206 bucks for the warranty, make sure it will cover the repairs and buy it. The screens are worth anywhere from $500 to $1100 to the right person, and for $200 bucks I would do it so that its covered for anything else that might happen.
Kris
#5
Registered User
Thread Starter
It sounds like it could be a couple things ....
- The cooling fan is shot and/or the motherboard controls for it are shot,
- Cooling fan/heatsink isn't in contact with the CPU,
- Bad thermal sensor (aka bad motherboard)
Thermal shutdown is normal and would happen under 90 seconds if the CPU gets too hot, and once that tempurature threshold is reached the circuit trips the main power and it shuts down until its cool enough to power back up.
Remove the thermal compound from the contact patch between the CPU and heatsink, then replace it with some Arctic Silver 5 and reassemble. Use denatured alcohol and a soft lint free cloth to remove the old thermal compound and residue before applying the new compound, which should be roughly half the size of a pea.
Make sure the heatsink/heatsink mounts aren't broken, as this would also cause the thermal shutdown issues I believe you're having.
If Dell wants only $206 bucks for the warranty, make sure it will cover the repairs and buy it. The screens are worth anywhere from $500 to $1100 to the right person, and for $200 bucks I would do it so that its covered for anything else that might happen.
Kris
- The cooling fan is shot and/or the motherboard controls for it are shot,
- Cooling fan/heatsink isn't in contact with the CPU,
- Bad thermal sensor (aka bad motherboard)
Thermal shutdown is normal and would happen under 90 seconds if the CPU gets too hot, and once that tempurature threshold is reached the circuit trips the main power and it shuts down until its cool enough to power back up.
Remove the thermal compound from the contact patch between the CPU and heatsink, then replace it with some Arctic Silver 5 and reassemble. Use denatured alcohol and a soft lint free cloth to remove the old thermal compound and residue before applying the new compound, which should be roughly half the size of a pea.
Make sure the heatsink/heatsink mounts aren't broken, as this would also cause the thermal shutdown issues I believe you're having.
If Dell wants only $206 bucks for the warranty, make sure it will cover the repairs and buy it. The screens are worth anywhere from $500 to $1100 to the right person, and for $200 bucks I would do it so that its covered for anything else that might happen.
Kris
Kris,
I would agree it sounds like a bad fan or motherboard that is what i am trying to determine. A fan would be a very cheap fix i need to know which 2 leads to put the 5 vdc on to test/confirm if it is good or bad .
I have already reseated the CPU and heat sink so i know that is all correct there but i have not personally tested the CPU.
There is a minor problem with your idea of putting the $206 dollar warranty on it with dell it must first be up and running so you can go online (with the actual computer to register) for it to become active . If it is dead, unless you have a clone to lend me that can't happen.
The shut down is very quick maybe 2-3 seconds after the power button is pushed and no beeps the only noise is the hard drive spin up.
When you plug in the ac adapter to the jack the light comes on to show it see's it and when you push the start button the power light comes on as well as the bluetooth light, the hd starts to spin up ( the fan does not even wiggle or try to go) then it powers down and the HD light gives a flash and the power light gives a pulse as well then that is it game over.
***** anybody know if the fan must come on first thing for boot up to continue ??? *****
My buddy has a dell N5010 which is a few months old -- at start up his fan comes right on full speed and then tapers back and cycles as needed. I have never seen this 1721 or any other 2 year old dell in action so i do not know if it should act the same.
#6
Okay I did some looking and this appears to be a common problem.
When you turn it on, how long does it stay on, what lights come on (num lock, caps lock, etc.) and how long does it take to shut down? Other than the fan not coming on, does it make any noises?
Most of the problems seem to point to a possible bad CPU, which can be picked up for cheap from Newegg or another retailer. If it does come down to a bad chip you need to make sure you have some thermal paste available to make sure there is a good transfer of heat from the chip to the heatsink. Arctic Silver 5 is sold in the small tube (roughly $7.99) and you can pick it up from the Egg as well.
Kris
When you turn it on, how long does it stay on, what lights come on (num lock, caps lock, etc.) and how long does it take to shut down? Other than the fan not coming on, does it make any noises?
Most of the problems seem to point to a possible bad CPU, which can be picked up for cheap from Newegg or another retailer. If it does come down to a bad chip you need to make sure you have some thermal paste available to make sure there is a good transfer of heat from the chip to the heatsink. Arctic Silver 5 is sold in the small tube (roughly $7.99) and you can pick it up from the Egg as well.
Kris
#7
Registered User
Thread Starter
Okay I did some looking and this appears to be a common problem.
When you turn it on, how long does it stay on, what lights come on (num lock, caps lock, etc.) and how long does it take to shut down? Other than the fan not coming on, does it make any noises?
Most of the problems seem to point to a possible bad CPU, which can be picked up for cheap from Newegg or another retailer. If it does come down to a bad chip you need to make sure you have some thermal paste available to make sure there is a good transfer of heat from the chip to the heatsink. Arctic Silver 5 is sold in the small tube (roughly $7.99) and you can pick it up from the Egg as well.
Kris
When you turn it on, how long does it stay on, what lights come on (num lock, caps lock, etc.) and how long does it take to shut down? Other than the fan not coming on, does it make any noises?
Most of the problems seem to point to a possible bad CPU, which can be picked up for cheap from Newegg or another retailer. If it does come down to a bad chip you need to make sure you have some thermal paste available to make sure there is a good transfer of heat from the chip to the heatsink. Arctic Silver 5 is sold in the small tube (roughly $7.99) and you can pick it up from the Egg as well.
Kris
When you hit the power button i get 2 lights the one indicating power and the other one that indicates bluetooth . The unit runs for exactly 4 seconds and then it powers down you hear a clunk from the HD as it stops and the HD light gives a flash. If you try it without the HD installed everything is the same except no noise of course.
It has got to be one of 3 things i think.
1-- fan bad ?
2-- CPU burnt ?
3-- bad motherboard ?
I am certainly no expert this is my first tangle with a laptop i know a lot of our fellow members know much more than i do about these if someone would please tell me what fan leads get the 5vdc both + and - positions i could then find out if the fan is ok.
Thank you for your help so far.
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