Inverter? no...LCD? no...So what?

[Lin1]

I'm new to this forum, and new to my current hobby/obsession of trying to resurrect old laptops. Someone gave me an old R52, XP Pro Sp 3, 1 GB. It runs fantastic. VGA is fine, but the screen is so dark that you can barely make it out. The perfect display is visible with a flashlight, so obviously the data/power cable is properly attached and functioning.

I eBayed a "tested working" inverter, but it didn't help. I then found a "tested working" LCD (with 1 bad pixel) for cheap, and then, (as per some Youtube guru) I plugged its little white cable into both the new and the old inverter (which were attached to the cable going to the LCD, and assumedly, then to the mobo) but still no light.

To the best of my knowledge, this laptop has never been disassembled. The screws still had the blue... stuff... on them. I did read somewhere that it might be a bad fuse on the mobo. I'm a bit confused about this...Might the part of the ribbon cable going to the inverter be bad? (Does the inverter and its cable do anything else but supply light?) Is a fuse an FRU? (I can solder)

Any other theories, before I break the whole thing down? Such a nice laptop...

Thanks.

[Neil]

Could be a blown fuse on the motherboard. There is a very tiny fuse near the LCD ribbon cable connector that I've seen go out before...cuts off the power to the inverter.

Could also be a broken wire in the cable itself somewhere along the path from the notherboard to the inverter. There are two or three connectors in the path as well.

[RealBlackStuff]

You can find an overview of the Fuse Locations on a T4x on my website (see link below).
It's not from an R52/T43 but almost identical, and good enough to do your trouble shooting.
You could also have a bad CCFL (backlight) tube.
If yours is a 15" machine, have a look at this LCD-offer: http://forum.thinkpads.com/viewtopic.php?f=11&t=105469

[Lin1]

Thank you.

I guess that's the danger of eBay parts; you never know about "Tested working" components, so you can never do a good job of troubleshooting.

I will install the new LCD, cable and all, just to make sure, before I deal with the fuse situation.

I also have a Vaio with plenty of backlight, but garbled data. Same new/replaced components. It must be a motherboard issue - although it works when my cat sits next to it. Go figure.