R51 with no video backlight

[billp117]

My R51 (Intel video) seems to work fine...but you can only see the screen by shining a flashlight on it. I replaced the inverter with no success. I replaced the LCD and still no luck. The inverter and screen came from a T42/T43. Any combination of these parts...still no luck.

Any suggestions?

[ajkula66]

I'm going to guess along the lines of a blown fuse on the motherboard.

Good luck.

[billp117]

I forgot to mention that video does work to an external monitor.

[ajkula66]

That really doesn't make a difference.

Is resolution on the new screen the same as on the old one?

[billp117]

Yes...they have identicle Samsung part numbers. They are VGA screens. The inverters are not the same...I will check them out further.

[ajkula66]

Take a look at this and proceed accordingly:

http://nickpaton.fireflyinternet.co.uk/ ... 0Fuses.pdf

Good luck.

[billp117]

The inverters are 91P7335 for the R51 and 26P8464 for a T40 series. The salvaged parts came from a working unit that I upgraded to SVGA+. I usually have little trouble upgrading or repairing screens. This one has stumped the band.

[billp117]

Thanks for the tips...but I will plug the inverter, cable and lcd into a good known working motherboard. If I can get them working I may just replace the motherboard. Fuses drive me crazy...and I throw in the towel rather quickly.

[billp117]

They do work on a good motherboard...hmmmmm.

[RealBlackStuff]

I've seen you mention them wrongly before.
There have been no VGA (640x480) or SVGA (800x600) screens on any of the Thinkpad models since the A2x/A3x/T2x, probably even further back.
Standards in 4:3 laptop format are XGA (1024x768), SXGA+ (1400x1050) and UXGA (1600x1200).
There are some exotic screens with even higher resolution.

[billp117]

My mistake...I meant XGA and SXGA+.

Also, my mistake...they do not work on a good motherboard. (typo).

The only last possible part would be the cable. Since I am out of replacment compatible parts it looks like this rescue may be doomed for a while.

[ajkula66]

Are we talking about 14" or 15" unit when it comes to R51?

[billp117]

14"

[ajkula66]

Well, an Intel-based R51 won't drive a 14" SXGA+ LCD to begin with. My understanding is that it might be possible with a modded LCD cable.

Good luck.

[billp117]

Thanks George...Let me help clear up the issues. This is a 14" R51 Intel based ThinkPad. It has an XGA screen. I am not trying to modify this to anything...just replace the XGA screen with another XGA screen. The replacement screen has the same Samsung part number and the inverter is a compatible item taken from a T40 series ThinkPad. I do believe the inverters are compatible.

The only culprit appears to be the XGA cable for the R51...I do not have a correct replacement compatible XGA cable to test with...(I did try a SXGA+ cable but that did not work).

I then connected each screen and inverter (and combinations of both) to a good working motherboard using the R51 cable and they still do not work. (Hope I did not blow something up on that motherboard)

In the mean time I can get an external monitor to work on the R51. I hope that helps clarify my situation. Thanks for taking the time to repond...you guys are great. This will probably be my first and last R51 rescue.

[richk]

It really sounds like a motherboard fuse, but some video chip issues have the same symptoms.

[billp117]

What confuses me is they don't work on a known good motherboard.

[misfit]

Take a look at this and proceed accordingly:

http://nickpaton.fireflyinternet.co.uk/ ... 0Fuses.pdf

Good luck.

Wow! Thanks so much for this George. I collect anything like this that I can as I'm an invalid and my hobby is messing with ThinkPads. Specifically any Pentium M machine through to T/R60s, although I do have a couple Tualatin machines, an X24 and an X30. (I no longer update my sig, it would change every week and there's a limit to sigfile size. )

I have quite a few machines put aside for when I get around to them. I seem to be buying more than I can work on at the moment as I think that the machines that fall within my... ummm, parameters are never going to be cheaper or more readily available. (Essentially I like machines that can run Windows XP and that don't need parts that are too expensive, such as SDRAM or slow 1.8" HDDs.)

My current favourite machines are T60 FlexViews and X31s (LOL, neither of which are actually relevant to this thread). I suspect that I'd like the X32 more than the X31 but I'm yet to 'meet' one.

Oh, I'm reading here as I just bought an R52 that won't charge the battery. It also won't boot on adapter power unless there's a battery present, then it only runs off the battery. Also it won't run from the battery alone unless it's plugged into the mains first. Heh! I get a bit side-tracked whenever I read here and hours can go by.....

Oh, I bought the R52 knowing that it had a problem and paid roughly what the 160GB IDE drive it's fitted with is worth second-hand so no loss if I can't get it going. However I love a challenge (when I have time, LOL).

Cheers,