Dell Inspiron 1545 video display

Someone brought me a Dell Inspiron 1545 laptop with a broken LCD. I ordered a new display with LED backlight. I installed the LCD, but when I powered up the laptop, it wouldn't work. I don't mean it wouldn't light up, it didn't work at all. Connecting it by the VGA port shows the video card is good. I tried the display on another laptop and other displays on this one with the same results. The new display is good, and no display will work on the Dell. I reseated the connectors on the video data cable with no joy and then repaced it with a new one. Still, it refuses to work. Setting the computer bios to default didn't help either. I never tried it before I replaced the LCD but the owner said it worked fine except for the broken screen. I don't know what else to try. Does anybody have an idea?

Thanks in advance,
Blufx

 

As this laptop is not functioning with any screen that you connect it sounds like there is another problem. Have you tested the old screen to see if it actually was dead?

Have you tried to get the diagnostics to run, hold down the Fn key while you are pressing the power button. If it then shows the diagnostics screen run the memory and hard drive tests. A faulty memory module could cause a blank screen, I've had this problem on a 1520.

 

markmadras,
Thanks for the suggestion. The old screen was broken, so I trashed it. I did have a couple other LED backlit screens I tried.
I try the to run the diagnostics in a little while.

Blufx

 

Sorry, I skipped this in your opening post. Are you saying that it displays as normal and all boots up ok when connected to an external monitor?

 

Sure does. I'm running the diagnostics and watching on an external monitor now.

 

After the tests, take a look in Device Manager and check that the graphics drivers are all ok and nothing is showing yellow triangles. Did the external monitor come on without you doing anything, if so try hitting Fn and F8 together, that should switch between the on board and external screens.

 

I had to hit fn + f1 to switch to ex. monitor. All of the test came out fine, although I was looking at them on the ex. monitor. A few wouldn't display correctly on the CRT so I skipped them. In the meantime, everything in the device manager looks good. I reinstalled the graphics driver for the heck of with no change.
I've read some replies to similar case in other forums and found some folks had to replace the motherboard. This doesn't make sense. How could breaking the LCD take out the mobo?

 

News flash,
I just found the display is working(I couldn't see it before), just not the back light. Remember, this is an LED backlit display with a new data cable. Still, no display will light up on it. Does this narrow down the possibilities?

 

You may be onto something, take a look at this,

http://support.dell.com/support/edocs/systems/ins1545/en/SM/display.htm#wp1109848

Near the bottom of the page it shows the Display Inverter, this supplies power to the back light. Have you replaced it as it may have blown.

 

I'll look, but as I said, this is an LED backlight. There's no inverter.

 

Just been looking through the manual again and as far as I can understand the correct switch to change screens is the Fn & F8 keys, have you tried that combination.

Understood, it was the old screen that was LCD with standard back light, are you sure the new screen is compatible.

 

It's fn+f1 on this one. f8 is for speaker

 

Yep, it's just like the page you sent except there's no inverter on this one. Funny, they put the same model, same numbers, with two different displays. There's no way to tell unless you open it. I ordered the first display by model number like I always do. I got a CCFL backlight display. I had to send it back and specify the LED.

 

As a matter of fact, since I had this CCFL display, rather than send it back, I advertised it Craigslist. One woman was going to drive about 75 miles to get it. She called Dell, gave them the serial number and read my ad to the tech. He told her it was exactly what she needed. After driving up here, I opened her laptop to find an LED display.

 

Ohhh the complexity of getting spares.

So what now. I'm out of ideas and obviously your laptop isn't quite the same as detailed in the Dell site manuals. Unless you find there is a connection somewhere that hasn't gone in just right when you reassembled I can only presume that something on the motherboard has died.

 

You may be right there. Here's a conversation from Dells forum. It sounds just like mine but ends with this: "Searching the web I have found 3 or 4 other people with backlight driver circuit failure after changing 1545 LED backlit screens. Sadly no solutions other than mboard change." Then another guy pops up and says: "Got the same problem here.

Actually, we've had the same problem twice within the last 6 days.

Dell really need to address this problem, because designing a laptop that requires a new motherboard when replacing the screen is just unacceptable. "

My customer picked it up a while ago saying he was going to let the IT guy at his work look at it.

 

Yup, could be a circuit that should have had a surge protector in it to stop further damage when the screen blows. A bit like a like bulb blowing and tripping the fuse.

Best of luck with whatever you decide to do. A phone call to Dell might help but only if you get to talk to someone who knows their stuff.

 

Maybe just a weak circuit. What good is a surge protector if you have to replace the motherboard anyway?

 

Thanks for all the input. I'll post back if I hear anything from him.

 

I was just suggesting that if it has fried the mobo because the screen has blown that a replaceable surge protector would have been handy. Obviously such a device is not incorporated on the MOBO, it was just a passing comment.