Several backlight DEAD!

[el_Capo]

I have a problem with 3 of the older computers in my collection (T21, T22 and 700X) which have their backlight burned out.... (when I illuminate them with the phone's flash you can see what the screen shows). In some cases they momentarily return to normal but only briefly. I was investigating and found a video on YouTube of an Indian who unsoldered a chip near the monitor connector into the motherboard, solving the problem....
as always any ideas or recommendations are appreciated...
Regards!

[panips]

Please make sure whether the CCFL is dead or it's the inverter board issue.
A simple solution (for me) is to get new LEDs (from AliExpress) and do some soldering works. Usually the led comes with 4 wires where

ren/voc: should be > 9V, I did not find any manual nor specs but I believe 9~20v is OK
yellow/enable: > 3.5v(?)
white/adjust: it depends but it CANNOT be floating (which is different than what I saw on some Japanese twitters or the LED keeps flashing, I can confirm that)
black/ground: hmm...

you can either reuse the inverter board or solder them to the mother board.

[SMA]

For the T21 the most likely cause is a broken LCD cable.
Read about it in this topic

viewtopic.php?t=45602

Might be the same for the T22.

[el_Capo]

Please make sure whether the CCFL is dead or it's the inverter board issue.

how i check this?? could you gave me some details?

A simple solution (for me) is to get new LEDs (from AliExpress) and do some soldering works. Usually the led comes with 4 wires where
ren/voc: should be > 9V, I did not find any manual nor specs but I believe 9~20v is OK
yellow/enable: > 3.5v(?)
white/adjust: it depends but it CANNOT be floating (which is different than what I saw on some Japanese twitters or the LED keeps flashing, I can confirm that)
black/ground: hmm...

do you have links??

Thanks for responses!!!

[panips]

Replace with known-working inverter board or ccfl and see if it works. Or, you may also check the outputting voltage of inverter board. If the inverter board does not work, you can also test the fuse. Sometimes it's just because of a blown fuse.

I don't know what e-commercial site you'd like to use but google with keywords "Backlight Strip Kit LED" might be helpful.

update:
might be the protection circuit of the inverter board if it blacked out after a while
might be bad capacitor if sometimes it works but sometimes it does not.

[el_Capo]

i found this one in aliexpress----
could you tell me if will works in my T21/T22??
https://i.ibb.co/MnZRfCH/Screenshot-202 ... 193624.png



https://www.aliexpress.com/item/1005007 ... ry_from%3A

[RealBlackStuff]

Those provide ONLY backlight, but NO picture.

T20/T21/T22 inverter FRU 10L1402 or 91P7741:
https://www.elecok.com/ibm-lenovo-think ... l1402.html
https://www.pchub.com/hitachi-invc571b- ... 1402-p6747

[el_Capo]

Those provide ONLY backlight, but NO picture.

If you notice, in my original post I explained that you can see data on the screen, that is, it provides information whenever you illuminate the screen with an external source (flash phone) from close by!
Greetings!
ps. I ordered a couple of LED strip bands from Aliexpress as well as the CCFL module

[RealBlackStuff]

Just in case: where would you put those "LED strip bands"?

[Luizapper]

Hello,

I've successfully done LED swap on a 770's 13.3" LCD panel.

Led option used: https://www.aliexpress.com/item/32612113107.html

You can check the solution and their results in this post
And the whole process to a LED swap/retrofit.