Totally Dead PC

My friend has a Dell. He called me over one day about booting problems. He described how it just stopped at a black screen one day. When he hit the power button, the hard drive spun up to speed and the PSU fan started but the monitor was blank. After checking the connections, I pressed F8 and selected VGA mode blind as I had memorized it's spot on the menu. Later I tried my monitor. No luck, so it wasn't a display issue.

So I tried pulling up the BIOS and got nothing after F1-F12, Shift, Spacebar, and Ctrl+Alt. I immediately unplugged and opened the PC. After checking that the BIOS chip was there, I swapped out the RAM, the fan + heatsink, PSU and got nothing.

Any suggestions? I can only think of:

-Dead motherboard
-Display adapter is broken/overheated

 

did the keyboard LEDs flash (or show any glow) at all pls?

any beep?

best wishes, HJ

 

!

I had the same fault with my Dell and it was the monitor.

 

Hugh Jarss - No, the box is silent any I wish the keyboard "lock" LEDs would flash but the computer does nothing but spin the fan and harddrive.

V.D.R. - I selected VGA mode blind and tried out my own monitor to no luck, so it's not a display problem.

Obviously, my friend doesn't want to buy another PC.

 

Dave,

suspect you have a problem on the +5 supply, have you got (or scrounge) a meter? convenient place to check is the 4 wire PSU connectors which plug into HDDs or CDROMS

measure between:
- red and black
- yellow and black
(doesn't matter which black you use)
(yellow wire is occasionally orange)

(fans and the HDD spin up are powered from the +12 rail)
(keyboard LEDs and most functionality from +5)

other things to look for
- motherboard capacitors (cylindrical metal cans w. plastic sleeve) particularly those close to where the PSU plugs in to the board: look for bulging or signs of leakage
- foreign bodies (maybe under the motherboard) in my case it was a metal spring clip from end of memory socket, had broken off and got lodged between the +5 and the chassis - amazingly, removed the clip and the thing worked again !
( "spare" case screws kicking around inside the box will also do this quite efficiently)

if you can get those voltage readings it would be very useful

best wishes, HJ

 

Disconnect any added hardware (PCI cards, USB, etc).

Disconnect all power and remove the battery for about half an hour.

After that I would suspect the graphics. It sounds like the graphics are built-in. If so, you would need an add-in graphics card to try, an AGP graphics card if it has an AGP adapter or a PCI graphics card that you may find in an old computer (the User Guide/motherboard manual should have information about upgrading/changing the graphics).

If it does happen to have a removable graphics card, take it out and clean the connectors with a soft pencil eraser.

Search for the model at the Dell Community Forums. Others may have had the same problem.

Matt

 

I would pull all IDE / SATA / Floppy / KYB / mouse / USB / cables both pwr and data. Disconnect monitor and pwr it up - most will give a "No Signal" or other short onscreen msg. Once you know display works try booting again.

Have had 3 systems behave as you describe and it was an internal short (one in a HDD, one was bad KYB, the other in a CDrom).

 

After probing several contacts with my trusty multimeter, I found that my friend's computer has probaly been fried. There is leakage of god-knows-what over the motherboard surface near the 12V input area. The Dell tech hung-up after my friend used the key phrase "lightning storm" so it seems like the PSU survived but the mobo did not. My friend is going to see if he can get a compatible motherboard somewhere and now, a high-joule surge supressor.

-Dave

 

rotten luck Dave

only...

sounds like a description of what sometimes happens from failure of electrolytic capacitor

if it really was down to lightning then damage is likely to be catastrophic;

but if due to elcap going pop then it's possible, even likely, that PCI cards, graphics & perhaps CPU have survived

elcaps can bulge (excess pressure inside) and leak - but also, fail more explosively (should have pressure safety vent but they don't always work...) which distributes the contents over quite a wide area

the contents end up as typically whitish / greyish / brownish deposit, really yukky, old days called it "chicken feathers" 'coz not just on the surface, muck stuck on top too. If it has "thickness" to it rather than just a film on the surface, is probably popped elcap innards

the ones nearest to where the PSU plugs in to the motherboard are the ones which fail most frequently - they have to take a lot of stress (particularly if smoothers in PSU are getting weak) - if it doesn't vent OK the gel / paste inside boils, the metal can goes pop, the foil and papery stuff inside splats out and sticks everywhere

motherboard will be kaput particularly as you have had volts on it with the leakage over the surface (BTW wash hands if you've touched the muck - it's not very good for you)

==

whether it's actually popped or just leaked badly, the 5V rail will have failed to short

- might try a card or two in another machine (as long as drivers for whatever card can be wangled) - if cards have survived then CPU should stand a chance.

don't want to raise hopes unduly - but would be a shame to spend more than you have to

best wishes, HJ

in my youth I used to let a few off come fireworks night... old ones didn't have vents - bung 'em on a variac and...

 

After I managed to borrow somebody's motherboard:

-The CPU is toast
-The hard drive can be recycled (with some bad sectors)
-1 of the 2 RAM sticks is usable (256 of DDR333)
-All the optical drives are OK
-Built-in video is non-removable (duh)
-The modem is working, but we'll junk it as he uses cable and they come for $20
- Miraculously, the 5.1 Sound card is in working order

Well, what's done is done but my I got friend a gift, a 6 outlet surge suppressor that also takes RJ-11, RJ-45 and coaxial lines and has a 15min. backup. Hey $150 is worth it so this doesn't happen again.

 

wow - one solid commonsense gift there - nice one

best wishes, HJ

 

I had a similar problem, would get two beeps soon after turning it on, then it would sound like things were going ok but nothing would proceed. I've tracked it down to the video card not connecting properly, so I occaisionally have to take the cover off and just loosen the card and then push it home properly, and then it's fine.