Power Surge killed Dell 8300

towger

Hi,

I may have had a power surge last week following a power cut. Since then my Dell Dimension 8300 is deal. :mad: Diagnostic LEDS do not light at all and neither does the power button. However when open I see a small green LED is lighting on the motherboad when the unit is connented to the power. Any ideas ? Thanks

Thomas_S_Hunterson

All modern ATX psus have a POWER OK line connected to the motherboard, so basically when the PSU is switched on, it does a self diagnosis, and if all it's voltages are correct, it sends 5volts (if my memory serves me correctly) down that line. If the mother board detects that this voltage is too far above or below the 5V, it can decide on a course of action, ie. to shut down to prevent damage, not to start up or whatever.
IMO it seems that your psu has failed as a result of the power surge, which i'm guessing was fairly substantial, because computer switch mode PSUs generally have fairly high surge tolerances. The great thing about them is that except in the case of a massive surge, they will generally protect the rest of your computer from damage, albeit by sacrificing themselves

cormie

Sorry to but in here, but in the case of a new laptop (battery powered) is it at less risk if the cpu is smart enough to detect higher voltage can it just switch off from that and use the battery instead?

Good luck with fixing you pc, I have no suggestions I'm afraid:(

Gurgle

cormie wrote:

Sorry to but in here, but in the case of a new laptop (battery powered) is it at less risk if the cpu is smart enough to detect higher voltage can it just switch off from that and use the battery instead?
(

How make power surge on DC side of transformer ?

cormie

Gurgle wrote:

How make power surge on DC side of transformer ?

Sorry, I don't know what you mean? Which is the transformer and which is the DC side of it?

Thomas_S_Hunterson

Mains power is 220V AC, the adaptor steps this down to generally 18-24V and rectifies it to DC, so the DC side is the bit that plugs into the laptop.

The Dimension 8300 is a desktop however as far as i know

towger

Hi, yes the 8300 is ( Was !!! ) a Desktop

Thomas_S_Hunterson

If you replace the power supply within the computer, it should start working again, failing that, the damage probably runs deeper and well...

towger

Yeah thanks .... my fear is that the PSU is ok ( given that power seems to be making its way to the motherboard ) but that the board and/or processor is blown.

Thomas_S_Hunterson

No, there would be power making its way to the motherboard, but because the power supply has done its self diagnosis and has found that its voltages are either above or below normal, the POWEROK line which connects into the motherboard, supplies a different to normal voltage (either above or below 5V) and the motherboard sees this and decides not to turn the computer on because of potentially hazardous voltages that could damage the computer. This, is the computers way of protecting itself against a damaged power supply,

I don't think you need to worry

maidhc

Make sure that non Dell PSUs work in Dell computers... Getting a Dell PSU might be awkward?

Unless you have bits and pieces handy you should probably just send it somwhere for repair and send the bill to your insurance company. I did it with my computer many years ago, and there was no hassle.

towger

Yeah .... was only the PSU that needed to be replaced luckily. Had to get it from the UK .... not cheap because a Dell cannot take a generic one. But as I can claim on house insurance I'm happy to pay up rather then chopping bits out of the case to make a generic one fit.

Drapper

had same problem with a 8100 :-) fried the USBs, last Dell I ever bought !

Gurgle

cormie wrote:

Sorry, I don't know what you mean? Which is the transformer and which is the DC side of it?

Mains = AC
Battery = DC

Theres a fair few things to get through from the plug to the laptop, including a step-down AC-AC transformer, a rectifier and a voltage regulator.

Thats all in the box-on-a-lead with the mains plug on one side and the laptop connector on the other. There will also be a fuse in the mains plug & one on the motherboard on the DC input.

Even if all that stuff was blown, and the fuses failed to blow (or didnt exist to save 12c in manufacturing) and the over-voltage managed to get as far as the laptop itself, the capacitance of the battery itself should be sufficient to prevent a power spike reaching the motherboard.

'Power surge' is the new 'RTFM Error'.

landser

towger wrote:

. But as I can claim on house insurance I'm happy to pay up rather then chopping bits out of the case to make a generic one fit.

why didn't you just claim for a new computer?

Thomas_S_Hunterson

Because that drives insurance up for the rest of us!

landser

sean_keevey wrote:

Because that drives insurance up for the rest of us!

OK, have you finished with the moral high ground??
he's claiming anyway and he would be entitled to claim for a new computer. the cost will be marginal to the company given that the major cost here will be the investigation.

Stephen

They're far less likely to engage in an investigation over the cost of a power supply unit than the cost of a whole new PC.

Thomas_S_Hunterson

landser wrote:

OK, have you finished with the moral high ground??

Thank you for at least confirming that i am right

MrPinK

Your insurance company will more likely want you to bring it back to Dell and let them replace anything that needs replacing, or decide if it's a complete write off.

Ruu_Old

if its insured as part of the Dell PC, they probably wont cover power surges, unsure though. It depends how big the surge was i guess, could have passed through your PSU and to the rest of the board. Unless it went down your phoneline in that case its hit the modem, try removing the cards one by one and try powering it up then.

maidhc

All I had to do to claim a few years ago was provide a "techicians" report that the modem had been fryed by lightening. It wasnt enought to have a receipt for a new one, nor was it eounght that it burn marks... A clown (for he was that) in a computer shop had to say it was a goner....

Snowbat

I had a power supply that usually wouldn't start after a power cut or brownout. It needed to be unplugged from mains for several minutes and plugged back in before it would fire up. Possibly it had a bad voltage protection mode that reset by removing power for several minutes.

kippy

something everyone should learn from this episode. Buy a surge protector-preferebly one with a phone line port as well.
To fix the problem as mentioned before you'll need to get a new power supply-keep an eye out on the web or ask a supplier to get you one-they are not that hard to fit.
On other thing-I assume you have tried a different power cord....I know-we live in hope....
Finally-

had same problem with a 8100 :-) fried the USBs, last Dell I ever bought !

You'd have the same issue with any standard PC without a surge protector built in.
Kippy

towger

In the end the cost was €50 for PCWorld to check it out and install the new PSU and €170 for new PSU shipped from UK.
Seems insurance will be happy to cover it ... only thing is they wanted a letter from the ESB confirming that there was a power cut on the given day. ESB obliged no problem ... it was the day a few weeks ago when 200,000 homes were knocked out for a few hours.

heffo9

just for the record dell machines can take generic psu's, i have a thermaltake butterfly 480w fitted to my dell dimension 4600

maidhc

heffo9 wrote:

just for the record dell machines can take generic psu's, i have a thermaltake butterfly 480w fitted to my dell dimension 4600

Not all. The 4600 can but the 8200/8250 cannot, I dont know about the 8300 but one would suspect it cannot.