Bad processor, PSU or Motherboard?

[techlink]

I am working on a Dell Dimension 4600 Win XP pro. It will not boot or even POST, the CD doors won't open but the fan runs and the HDD spins. I scanned the HDD in another computer it is clean. Tried a differnt video card, removed all cards (modem sound even video) still won't boot or POST. How does one tell if the processor us bad without swapping it out with another?
The PSU shows no light on the -5v on a tester, could this cause all of the above problems and does Dell still require Dell only power supplies or can a generic work in it?

 

[gbaughma]

Without -5v, you have no logic gates. It's the power supply.

As far as using a generic power supply, it depends on the system. If the power supply physically fits, and has the necessary connectors, a generic supply should work fine.

Of course, if it's under warranty, use only certified replacement parts.



Just my 2¢
"Life gets mighty precious when there's less of it to waste." -Bonnie Raitt "Nick of Time"
--Greg

http://parallel.tzo.com

 

[techlink]

thanks for the quick reply. I did notice that the cd drives will open if they are not connected to the ribbon cable. I will get a power supply ordered. I had heard that Dell was proprietary on their psu's is that only on the older models? From what I have read this model will be ok with a generic, does this sound right to you?
Thanks again

 

[gbaughma]

It depends on the model of Dell.

Many of the dells, including newer ones, have proprietary PSU's, Mobos, etc. But, some of the Dimensions had standard PSU's.

My wife has an HP, and her PSU just went out.

A regular PSU fit (we put in a 500-watt with an oversized cooling fan), however it took a little dremmel work to modify the tin on the back. One little tab was sticking in the way of the power connector. ZIP! Gone... fit... happy wife.



Just my 2¢
"Life gets mighty precious when there's less of it to waste." -Bonnie Raitt "Nick of Time"
--Greg

http://parallel.tzo.com

 

[techlink]

Just installed new psu still no POST or boot, nothing has changed. Could this be a CPU failure? How can you tell without swapping it out.

 

[techlink]

I noticed that the HDD won't spin if the IDE cable is plugged in but if I unplug it the drive will spin, it's the same with both CD drives they won't open if the ribbon cable is plugged in but if unplugged they will open. Could this be MOBO related?

 

[techlink]

Looks like I'm in a quandry as to what to do with this computer in appears the only way solve this is to either swap out the CPU or motherboard however being a Dell it is going to require a Motherboard from dell($140.00 for a reman), because the recovery disk will only work on that paticular board, sounds like an expensive fix to me. I think it would be better to put in a new generic motheboard and new CPU and RAM than to get remanufactured parts from Dell. The problem I see with this scenario is that I will also need to get a new OS disk because the Dell recovery disk won't work on another board. Is any of this sound correct or am I barking up the wrong tree?

 

[wahnula]

techlink,

Sorry about your Dull, er, Dell problems. Sorrier still that you had to buy a Dell PSU to find this out. Before trashing it, I would remove the MB from the case, remove the CPU HSF, and reseat. Then, with the MB on a folded towel or piece of foam, try booting into BIOS with only PSU, CPU, monitor, PS/2 (wired) keyboard & mouse, and one stick of RAM installed, no HDD no optical drives. If you have more than one stick of RAM try swapping. If no POST in this config then yes, something is bad, and it may not be the MB. I would hate to see you throw good money after bad. I believe you are correct that your XP install is married to your Dell hardware, but a Repair Install on your old HDD in new hardware might work, never tried it.

If the PC does everything you want it to do and you are happy with it, then I would take it to a local shop and pay for a diagnosis. It will save you from buying the wrong part again (maybe!). Best of luck.

Tony

 

[techlink]

Thanks for the reply Tony, I think I have done most of what you have suggested with the exception of removeing the motherboard and booting with it out of the case. As for buying the PSU I needed one on hand anyway but it is a generic not a Dell which from what I've read this Dell will work with a generic. The RAM must be in pairs on this MOBO, I am waiting on a shipment so I can swap it out. I really think we are looking at a CPU failure but I don't have another P4 board to test it in or another processor to test the MOBO as for taking it to a local shop... that would be me, the owner already called another shop and wasn't satified. I think I can put in a new MOBO, CPU, RAM & OS cheaper than I can fix this one with Dell parts.(in case you haven't noticed I'm not very fond of Dell computers!)

 

[wahnula]

I really think we are looking at a CPU failure but I don't have another P4 board to test it in or another processor to test the MOBO

Buy both! As a repairperson you will surely find both of them useful in the future! I believe I have spares of every common socket MB and one of each socket type CPUs (even Pentium Pro) plus a whole box of Video/Sound/NIC/modem/wireless/ISA cards for testing purposes, and I'm just a PC hobbyist (well I do maintain my office fleet).

eBay is a decent source but you are always taking a chance as the product has an unknown history. If you are a pro tech you should buy a Socket A, 478, 775, 939, 940, AM2 etc CPU & MB, keep them in their original boxes. You will save a lot of time in the long run. Since $140 is not that expensive for a MB (well maybe a Socket 478) you have a 50/50 chance of fixing the problem and the same chance of having a working spare.

The reason I asked you to remove the MB is in case anything fell behind there and is shorting traces. Remember the first-ever "bug" in a computer was just that!

Tony

 

[techlink]

I undertand what you are saying. When I say I am the local shop, I am, but a very small home based business with a small budget. I do have some spare video, sound, MOBO and processors just not the one I need for this project. I don't like to buy older processors and mobo's that I may never use again if there is another alternative. I don't have enough turnover to justify buying one of everthing. I may work on a computer once every couple of weeks. Looks like I may have to spring for one in this case.

 

[techlink]

Well I managed to come up with another processor that was the problem, must have fried when the PSU went.

 

[wahnula]

Well I managed to come up with another processor that was the problem, must have fried when the PSU went.

Excellent! Thanks for posting your remedy, many people do not bother. Glad you did not buy a MB you did not need.

Tony

 

[MaxEd]

If you live near a Fry's electronic store you can take it in to have them test your mobo/CPU. Just tell them you bought it from them years ago or just talk real nice to person who is bored out of his mind doing the testing . I've managed to use their service for free to find out a bad mobo.

-Laughter works miracles.