Computer Problem

[TB Roye]

When I got my iMac I shut down my 4year old Dell, disconnected the monitor and put it away. The other day I decided to move some of the files over, pictures and some documents. Connected every thing a started it, the fans all started turning no beeps or anything but no picture, monitor said no video signal, tried another monitor same thins. The computer has built in video and VGA and HDMI out put tried both same thing "no video signal. Was tempted to go buy and cheapo video card and try it but have held off. Could it be the little Bios/CMOS battery on the mother board? or a dead onboard video. Every thing was working fine on the day I shut down no problems at all. Maybe it got mad because I left Windows. I might have to dig out the start up disk and see if I can remember out to do it.

Tom

[Cochese]

The problem isn't the video, the problem is it isn't booting. Clearing CMOS is a cheap and easy possible fix, but be prepared for anything. Check your connections while you have the case open. Look for a CMOS clear button, doubtful with a factory computer.

Edit: It's entirely possible your computer is posting without audible sounds, but I doubt it.

Here's a good guide: http://www.tomshardware.com/forum/26...video-problems

Sent from my HTC One using Tapatalk

[TB Roye]

Think I will try clearing CMOS first. Still don't understand why it is not booting when it was in September. Will try that tomorrow and see what happens, need to got to Dell sight and find out where jumper is.

Tom

[LCHIEN]

cmos battery should be good for a lot more than 4 years.

I think there's some POST audible signals if a video card is not found, however, some video problems may be a good card and video generator (which would look to the BOIS like an OK card but the output signal is not OK for some reason. Which would not sound the audible signal.

[TB Roye]

Found the computer is only 2 years old so the battery is probably good will clear the CMOS now that I found out where the jumper is and go from there. This computer is quiet never have heard any beep at any time. I will use the original monitor when I try again, gave to my wife as I had 24" on it, so I will put it back to stock and see what happens.

Tom

[mpc]

Do you see any text on the monitor at all - before the system even tries to boot? If you don't see anything at all - not even quick text or pages that flash by in a heartbeat - it's a problem long before the boot process starts. Usually there will be beeps too. That leaves:
power supply
CPU
motherboard
memory
as the primary items to check.

Some recent motherboards have a 2-digit LED display on them ("port 80" diagnostics) for the BIOS to report issues; these supplement the speaker beeps. A quick test is to remove all memory sticks (power off of course!) and then try starting the system; that should generate a few error beeps. Without any memory, the BIOS can't do much of anything so it beeps. If you don't get beeps - and know this system does in fact have a speaker of some sort - that leaves 3 potential items: CPU, motherboard, power supply. Re-seating power supply connectors can make a big difference.

Another thing that stops a PC from doing much is a device that has its power supply leads shorted to ground - i.e. a hard disk or CD/DVD drive with an internal short keeps one of the power supply voltages stuck at zero. Depending on which voltage line is shorted to ground, the power supply might not even start - the whole system acts like it's unplugged. Unplug the power leads from the various non-motherboard items and turn the power ON... if the video shows signs of life now... power down, plug one item in, and power up again. Repeat until you find out which device locks up the system when it's plugged in. If unplugging disks, DVD drives, etc. does nothing, how many cards are plugged into the motherboard? They can have the same issues; removing them (power unplugged completely since many motherboards have some power ON even with the system OFF) is another simple test.

You said the system is only a couple years old so it should be new enough to not be affected by the infamous electrolytic capacitor problem: quite a while ago, one of the companies making electrolytic capacitors (the physically larger ones on the motherboard, they're used to reduce ripples in power supply voltages) produced millions of capacitors with a screwed-up chemical mix inside (the electrolyte); they missed the stabilizing chemicals. After a couple years, the electrolyte in these capacitors would expand, bursting through the casing of the capacitor... and whatever job that cap was supposed to be doing didn't get done - usually power voltages to the motherboard or CPU got noisy and the system would be unstable or wouldn't start at all. Such capacitors are easily identified: on the top of electrolytic capacitors (which look like cylinders standing upright on the motherboard or lying like storage tanks on the motherboard, they'll have a thin rubber/plastic insulation coating on them with writing) you often see an "X" shape stamped into the metal canister. If that area is bulged outwards at all the capacitor is dying. When really bad, the X splits open, or the other end of the cap splits open, and a brown scum (the electrolyte) squeezes out. Such caps are found in pretty much every electronic device - not just PC motherboards. These bad caps also took out the automatic transmission computers in Eclipse/Laser/Talon cars for example.

mpc

[Bill in Buena Park]

Does "built in" mean integrated into the motherboard and not on a separate video card? Also - beside the fans running, do you see other signs of power to the motherboard (power lights, etc.), and does the hard drive spin up and sound like its running normally?

After checking your connections to the monitor - long shot, but I've run into situations where after a couple years, something like tarnish may build up on contacts for cards seated into the motherboard and pins on connects. I've had some success taking an abrasive pad with a few light passes over the contacts or pins (careful not to bend anything) and seat/reseat a couple times to ensure good contacts.

[LCHIEN]

as an electrical engineer very familiar with printed circuit boards I know the edge contacts on the plug in computer cards have a very thin layer of gold (often 5 microinches) so sanding or abrading on them is Strictly verboten!

THe best way to clean them is with a gum eraser. Usually, gold does not tarnish so this will clean any dirty film off. If that's the problem.

[Bill in Buena Park]

Loring, are the contacts always gold? Film might be a better description than tarnish - but it appears "oxidized" - so maybe cheaper-than-gold materials? I've used eraser successfully as well, but never sanding. More like a polishing pad.

[woodturner]

Loring, are the contacts always gold? Film might be a better description than tarnish - but it appears "oxidized" - so maybe cheaper-than-gold materials? I've used eraser successfully as well, but never sanding. More like a polishing pad.

The Molex type connectors used to connect power to the components usually use a tin coating and are a common cause of connection problems. Simply unplugging and re-plugging all the connectors may fix the problem.

[Condoman44]

I agree with Woodturner, I have a self made desktop that every year gets stupid. I just unplug and replug the IDE connections and all is better till it happens again.

Good luck.

[LCHIEN]

Loring, are the contacts always gold? Film might be a better description than tarnish - but it appears "oxidized" - so maybe cheaper-than-gold materials? I've used eraser successfully as well, but never sanding. More like a polishing pad.

PC board edge connectors for signals are almost always gold plated but the trend over time is for thinner and thinner platings to be used. Power connectors are beefier and often tin plated as the currents are high and the contacts are bigger and have more spring force and engagement distance to break the surface oxides.

[lrr]

Tom,

Do you have anything plugged in that was not attached before? I bought a 1TB external USB drive for our desktop Windows PC (older Sony WinXP PC) and if the drive is powered up when the PC is turned on, the PC just hangs. Nothing displayed, no errors, etc. if the drive is off when PC is powered on, it boots up fine. Then when drive is powered on, it can be used.

[TB Roye]

It has an integrated(on board) video card, when I start the computer and Monitor all I get is no video signal, tried 2 different monitors. The fans all start but no beeps of any kind. I will take it out in shop and on the work bench this afternoon and see what I can do. It was working when I shut it down after getting my iMac. Personally I think Bill Gates put a curse on my for going to Apple. The computer has been trouble free since I bought it other than getting virus that required me to reload Windows 7 I will reseat all the connectors, plugs and cards and then clear CMOS and see what happens. Bad thing is I forgot to back it up before shutting in down. Mainly it the picture I want off of it.

Tom

[woodturner]

Tom,

Do you have anything plugged in that was not attached before? I bought a 1TB external USB drive for our desktop Windows PC (older Sony WinXP PC) and if the drive is powered up when the PC is turned on, the PC just hangs.

Are you using the USB ports on the front or the back of the PC?

I've had similar problems with external USB drives that are powered from the USB. The rear USB ports are usually mounted to the motherboard and meet the 500 mA power spec, while the ones on the front often only meet the 100 mA spec. As a result, the front ports cannot supply enough power to operate the drive consistently.