700C Display Turns Off

[MunkyCheez]

Hey everyone,

I recently received a 700C, which seems to be in pretty good physical shape (the keyboard is absolutely perfect!). The problem I'm experiencing is as follows: Only sometimes will the LCD turn on when I boot it up. Most of the time, though, it will just stay off while the computer continues to boot. On the times that it does work, it usually will go off again within about 30 seconds.

It doesn't seem to be a loose connection (although I guess it's possible), as I had it sitting perfectly still when this happened, not rocking it or moving it. The machine outputs video through VGA just fine, regardless of whether the internal LCD is working or not, so I don't think it's the motherboard.

Also, when the LCD does work, it looks fine... it neither looks dim nor strange in any other way. This seems to be a somewhat lightly-used ThinkPad... Those two things combined lead me to believe that it is not the fault of the backlight. Could it be the inverter? Your help would be greatly appreciated -- I love restoring classic ThinkPads!

[mnowell69]

seems very likely that it is the inverter. At a certain angle, even with a faulty inverter, it can be possible to see something on the screen. better if it was in dos mode because you would have the contrast of black against white. Guess the solder could be faulty on the backlight connections too. Can't imagine it would be a fault with the screen cable because as you said, moving the screen does nothing. Not much help i know.

[MunkyCheez]

seems very likely that it is the inverter. At a certain angle, even with a faulty inverter, it can be possible to see something on the screen. better if it was in dos mode because you would have the contrast of black against white. Guess the solder could be faulty on the backlight connections too. Can't imagine it would be a fault with the screen cable because as you said, moving the screen does nothing. Not much help i know.

That's what I was afraid of, as there's pretty much no way I'm going to be able to get a new inverter (eBay turns up empty ). I've seen LCDs with dead backlights and inverters, and you can still see what's being displayed when you're in a room with ambient light or you shine a flashlight at it, as you described. However, with this 700C, it seems to be all or nothing -- when the screen "dies", not even the LCD panel itself is outputting any video. I'll check again though, just to be sure...

[MunkyCheez]

Also, there are actually a few 760Cs on Craigslist right now. Could I swap over the entire lid assembly to my 701C? What about the panel? Or just the inverter?

EDIT: Then again, if I bought a 760C, I would probably leave it alone if it works. But I'm still curious about swapping in case I find a broken 760C with good LCD assembly or something.

EDIT: What about a 365XD?

[mnowell69]

i don't believe they are compatible, but i'm not 100% sure because there were 2 types that went into the 701c. You may be lucky by trying to re-seat the connectors for the panel, if you haven't tried this already. you could always put a WANTS AD in the marketplace because all the guys here have tons of stuff

[MunkyCheez]

i don't believe they are compatible, but i'm not 100% sure because there were 2 types that went into the 701c. You may be lucky by trying to re-seat the connectors for the panel, if you haven't tried this already. you could always put a WANTS AD in the marketplace because all the guys here have tons of stuff

Okay, I'll try re-seating both sides of the panel cable before I put up a WTB ad. Thanks for your help!