Computer Display Help

vpharris · 17th April 2009, 03:49 PM

I have a problem with the flat-screen display for my Dell desktop computer system, circa 2003. It often doesn't 'wake up' after it's been to sleep for a while. It appears that it's trying to, but something is preventing it. A good rap on the thing usually brings success. I'd like to know anything I can find out about the hardware interface that tells it to come back to life so that I know where to probe for some signal problem. I haven't found a schematic for it on the internet. I assume that the design is somewhat generic regarding the part of its operation that is having a problem.

Any suggestions would be appreciated.

Specific troubleshooting, pointers to good forums about PC hardware issues (I spent lots of time with google hits without much success. Plenty of sites telling you to check that it's plugged in...) or sources for a schematic or definition of the typical interface to a computer would be great.

A more detailed description if you're interested:
Dell model E151FPb
After some period of time without use, or if I turn off the computer and not the display, the display blanks (goes dark) and the power LED on the display changes from green to amber.

When I turn the computer back on, move the mouse, or touch a key, the display should come back on, but it usually does not. It appears to 'try to' do so. It blinks slightly very briefly such that I usually can see some sort of image on the screen but then goes dark again.... and the power LED blinks also- to green then back to amber. This repeats ad infinitum (forever).... with the power led blinking and such.

With a good rap on the thing, usually it starts up and then works ok until next time I let it go to sleep. So I'm thinking it must be hardware, and a crucial wake-up signal isn't making a good connection (maybe?). It seems that there isn't a lot wrong.

Thanks for any help!

Spiny · 18th April 2009, 07:41 AM

my experance suggest that if you hit something and it starts working you have a dry joint (bad solder connection) or bad connection somewhere.
LCD panels usually have various pcb's in them with ribbon interconnects, these can creep with heat cycling.
Try as a first attempt opening the panel unplugging all connectors and plugging back in. I suspect that will cure it

If this is a dell with a 15pin socket on the back not a captive cable check the cable end plug for a bent pin.
Captive cables can have cable breaks in the wire, wiggiling the cable will restore the display in this case, not just raping on the casing.

vpharris · 20th April 2009, 07:39 PM

Thanks... I hadn't been thinking about plug connections, but that's a good point and I'll give it a check.

dangus · 23rd April 2009, 06:16 PM

A lot of LCD monitors have failed because of bad electrolytic capacitors. I don't think your symptoms fit, unless they are just marginal. Failed caps are almost always bulging or burst at the top (for radial lead caps).

Another problem that might be relevant is bad solder joints on transformers. But, try a new cable first (if it is a replaceable one); that's a lot easier to test than prying the back of an LCD monitor open...

17th April 2009, 03:49 PM	#1
vpharris diyAudio Member Join Date: Dec 2001 Location: Philadelphia	Computer Display Help I have a problem with the flat-screen display for my Dell desktop computer system, circa 2003. It often doesn't 'wake up' after it's been to sleep for a while. It appears that it's trying to, but something is preventing it. A good rap on the thing usually brings success. I'd like to know anything I can find out about the hardware interface that tells it to come back to life so that I know where to probe for some signal problem. I haven't found a schematic for it on the internet. I assume that the design is somewhat generic regarding the part of its operation that is having a problem. Any suggestions would be appreciated. Specific troubleshooting, pointers to good forums about PC hardware issues (I spent lots of time with google hits without much success. Plenty of sites telling you to check that it's plugged in...) or sources for a schematic or definition of the typical interface to a computer would be great. A more detailed description if you're interested: Dell model E151FPb After some period of time without use, or if I turn off the computer and not the display, the display blanks (goes dark) and the power LED on the display changes from green to amber. When I turn the computer back on, move the mouse, or touch a key, the display should come back on, but it usually does not. It appears to 'try to' do so. It blinks slightly very briefly such that I usually can see some sort of image on the screen but then goes dark again.... and the power LED blinks also- to green then back to amber. This repeats ad infinitum (forever).... with the power led blinking and such. With a good rap on the thing, usually it starts up and then works ok until next time I let it go to sleep. So I'm thinking it must be hardware, and a crucial wake-up signal isn't making a good connection (maybe?). It seems that there isn't a lot wrong. Thanks for any help! __________________ Vince Harris

20th April 2009, 07:39 PM	#3
vpharris diyAudio Member Join Date: Dec 2001 Location: Philadelphia	Thanks... I hadn't been thinking about plug connections, but that's a good point and I'll give it a check. __________________ Vince Harris

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18th April 2009, 07:41 AM	#2
Spiny diyAudio Member Join Date: Feb 2008	my experance suggest that if you hit something and it starts working you have a dry joint (bad solder connection) or bad connection somewhere. LCD panels usually have various pcb's in them with ribbon interconnects, these can creep with heat cycling. Try as a first attempt opening the panel unplugging all connectors and plugging back in. I suspect that will cure it If this is a dell with a 15pin socket on the back not a captive cable check the cable end plug for a bent pin. Captive cables can have cable breaks in the wire, wiggiling the cable will restore the display in this case, not just raping on the casing.

23rd April 2009, 06:16 PM	#4
dangus diyAudio Member Join Date: May 2004 Location: Vancouver Island	A lot of LCD monitors have failed because of bad electrolytic capacitors. I don't think your symptoms fit, unless they are just marginal. Failed caps are almost always bulging or burst at the top (for radial lead caps). Another problem that might be relevant is bad solder joints on transformers. But, try a new cable first (if it is a replaceable one); that's a lot easier to test than prying the back of an LCD monitor open...