Backlight issues after Inverter Replacement on TP R31

[RobinD]

Hi everyone, here's my first post, hope you can help me out. A few weeks ago the screen on my Thinkpad R31 went very dark leaving only a faint trace of what was actually on the screen (if you looked hard enough!). I suspected the inverter pretty much straight away so ordered a new one from IBM (correct one!) and installed with no problems. Now when I run the laptop from the battery only everything is fine (apart from the brightness setting rolling back to dark after only 3 bars) but when I run it from the AC adaptor the screen is permenantly set to the lowest setting, ie very hard to see! No amount of brightness adjustment with Fn-Home will boost it (although the bars seem to increment with no effect!). I've trawled through the BIOS and everything is set fine, even fiddled around with different setting and nothing seems to cure. I know it's not a problem with my power settings as I've adjusted these to no avail.

Having looked through some other posts on this forum I came to the conclusion that I need a program to reprogram an on-board EEPROM to set the Inverter configuration for my laptop. I've also learnt that IBM don't like giving this software out, so does anyone know where I can get a copy of it?

It's a bit off that IBM will flog you a new inverter board and not give you the config software to make it operate correctly with your machine!

Thanks for any help.

Regards,

Robin

[danieldavid]

Hi Robin,

I wish I could help you - as I faced a similar problem a few months ago when I was preparing to replace the inverter on my R31 2656 77U.

Luckily, it turned out that the inverter supplied by IBM worked correctly right out of the box with the LG Philips 14" (labeled: LP141x10) on my Thinkpad.

When I ordered it, the service rep wanted the exact model and serial numbers.

At the time I was not able to get a copy of the Utility Diskette. IBM seems to be zealous about not sharing it because it can also be used to change the Thinkpad's ID number.

If I were in your situation, I would probably try to contact IBM quoting page 24 of the "ThinkPad R30/R31 Hardware Maintenance Manual" : "The EEPROM on the inverter stores its supported LCD type ID code. If you replace a LCD with one of a different brand or use a new inverter, the ID information in the inverter EEPROM should be updated. "

It may also be possible to visit an authorised service center that can run the diskette for you.

Another solution might be to find a used inverter on eBay removed from an R31 with the same type LCD as yours. These are sometimes sold as R31 cover with broken LCD...

Please keep us informed about your progress.
-Daniel

[RobinD]

Thanks Daniel,

I'll contact IBM and try to find a local service centre who can hopefully reprogram the inverter.

Keep you posted!

Regards,

Robin

[danieldavid]

Hi Robin,

Here's the link to the R30/R31 Hardware Maintenance Manual I mentioned:

http://www-307.ibm.com/pc/support/site. ... MIGR-39797

The utility diskette used for porogramming the inverter is mentioned on page 24.

By the way, what size and brand LCD do you have in your R31?

Best regards,
Daniel

[RobinD]

Hi Daniel,

I'm not sure of the brand but it's the 14.1" display.

I notice that on p220 (p226 in acrobat reader) of the maintenance manual (which I incidentally used to replace the inverter board!) it lists a 13.3" and 14.1" TFT LCD-Inverter part number 26P8139 and another 13.3" and 14.1" LCD-Inverter SUMIDA board part number 26P8153.

I'm not sure which I have as it was my dad that ordered it for me, but I'll make sure and find out from him.

Will find this out tonight and send an email to IBM asking about the EEPROM programming diskette.

Thanks for the continued help Daniel.

Regards,

Robin

[danieldavid]

Hi Robin,

Just checked again, the original and replacement inverters in my R31 (type 2656 77U) were the FRU 26P8139.

If you still have the defective inverter, you may be able to compare it to the replacment part you installed.

I just saw that IBM lists only the 26P8139 in its "LCD FRU parts list - ThinkPad R30, R31" (available at: http://www-307.ibm.com/pc/support/site. ... 39722.html ).

Regards,
Daniel

[RobinD]

Hi Daniel,

Finally got my hands on the box for the replacement inverter and it is indeed the 26P8139 Inverter.

I'm still to get in contact with IBM over the matter which I will do tonight now that I have the inverter part number and order reference.

Thanks!

Robin

[RobinD]

Have justchecked and the old inverter that was faulty has exactly the same part number as the new one.

It would seem that the EEPROM would need programming regardless of whether it was the same as the old one or not.

Perhaps the new replacement inverter boards are generic and can replace either of the old boards and such need programming?