Where is the fuse for LCD on a T20?

[Unknown_K]

I have a T20 that had no backlight on the 13.x" LCD. I replaced the inverter with a known good one (old one had 2 brown overheated sections under the plastic so figured it was bad), still would not work. I tried that panel on a T21 I have (which has other issues) and it lights up but is very pink and seems to throb a bit (needs a new CCFL but does work in that system). So I tried a working 14" on the T20 and still nothing, I asume there is a blown fuse for the LCD backlight, where is it and what type/value do I need to replace it with?

[RealBlackStuff]

On a T23, that would be fuse F4, the green square next to the mobo's LCD connector with marking looking like 7XL.
T20/1/2 are probably the same.
Don't know it's value.

[SMA]

On a T20, the fuse for backlight is F4. It is located on the bottom side of the board - just below the lcd connector.
Generally, you can find the value of a fuse, by looking at it's top marking.
In case of F4 it should have an 'N' as top marking, which means it's value should be 2A.

[Unknown_K]

Ok, took it apart and tested the F4 fuse, it is open. Yes it has a "N" for the value. Where do I find a replacement for that fuse, and what is the part number/type for that so I can look it up?

Can I just solder a new one over the old one (looks very tiny).

[SMA]

RS Component has them. The part number is 131-555

[RealBlackStuff]

It's a fairly large item for an SMD component which you should be able to unsolder.
But you can solder a good one piggy-back on top of it, if you like.

[Unknown_K]

Actually it is very small compared to the fuses on the top of the motherboard (not referring to the fat resettable ones).

[rkawakami]

Where do I find a replacement for that fuse, and what is the part number/type for that so I can look it up?

In case of F4 it should have an 'N' as top marking, which means it's value should be 2A.

Here's two Littelfuse catalogs of surface mount fuses:

http://www.littelfuse.com/data/en/Data_Sheets/448.pdf
http://www.littelfuse.com/data/en/Produ ... tFuses.pdf

Several different series fuses are used in Thinkpads; 434, 448, 451/453, 466

You can usually buy them in single-unit quantities from digikey.com or mouser.com.