T 22 Back Light

[t-rex]

Hello hope someone can help
T22
The back light started flickering. It seemed to have a problem with
the switch for the lid. I cleaned it upand it seemed fine and gave it back
(Wifes computer). About a week later it went out completely. I broke the
screen bezel at the bottom when i removed it because the inverter was stuck to
it. the board looked to have over heated. Easy enough i thought and found one
on Ebay for $9 shipped from hong Kong. When it came it looked like the old one
the Clear plastic was yellowed or should i say i belive it should be clear. Long
story short it did not work. Then i looked at the switch and it was N\O and
surface soldered to the board so i removed it. Still no working back light. The machine
does run i can see it with a flash light.
Heres a couple of pics:

http://img.photobucket.com/albums/v203/ ... erter1.jpg

http://img.photobucket.com/albums/v203/ ... erter2.jpg

The new board is on the top in both pictures. Or rather the one sent by the Ebay seller
I know that they cannot look like this new. So is the board bad? with all the flickering
i could see how it could get hot. Bad bulb? will one from an A21E work?

[RealBlackStuff]

I don't see anything wrong with the new inverter.
When you take out the LCD switch, you have to solder in another switch or a wire to 'bridge' it.

[t-rex]

When i checked the switch it was open (lid up) so i assumed it was normally open.
when i closed it there was continuity between all three legs.
So with the screen up there should be a connection between two of them.
so again i assume that if there is continuity between all three with the screen down
that i won't hurt anything poking around with a jumper wire. and it also explains why
nothing else worked. It sounds like a well placed drop of solder will fix it.

[RealBlackStuff]

Such a switch would be normally closed.
When you close the lid, it would disconnect something, and open the switch.

[t-rex]

yes you are most likely right, a micro switch with a broken contact
could act all kinds of strange. i'll look at it tomorrow it's my project for
downtime at work. As i remember there is not much room to do much in
there. the subboard its on is partially under the mother board. So i'll have to figure out how to jump it before i get it all apart. what exactly is that switch called? i've been googling
looking for a schematic.

[rkawakami]

Surface mounted pushbutton tactile switch, could be one such term for the microswitch on the I/O board. It's been quite awhile since I had one of those out of a T2x system to give you a better answer. To our knowledge, there is no publicly available circuit schematic for these Thinkpads, nor a bill-of-materials list where you might be able to get a complete part number and/or manufacturer. All of the various parts I've found replacements for in these systems (fuses, inductors, switches, etc.) has been done by searching mouser.com and digikey.com and checking datasheets.

[RealBlackStuff]

Your best bet would be to get a (used) I/O board, with P/N 28P8006, about $6.- + shipping
Check eBay for "T22 i/o board"