Help revive my X24...

[Quattro]

Well, I've acquired a dead X24.

It does not power up, however, the green light (LED closest to the power button) comes on when power from the battery or AC Adaptor is present.

I have now taken it completely apart, and traced the problem down to 3 possible sources. I think the 3rd picture is causing the problem, however, the first two may be linked. I'm thinking a liquid of some sort may have been spilt, although it does look relatively clean inside, and the case has never been opened.

1. http://rfincorporated.com/X24/brectangles.jpg

2. http://rfincorporated.com/X24/chip1.jpg

3. http://rfincorporated.com/X24/3.jpg

I'd really like to save this thing from the garbage bin, so ANY help or insight would be greatly appreciated. It is in perfect condition otherwise, flawless shell, nice keyboard, perfect LCD.

[brandon]

I don't know which parts have been damaged, but you can probably order replacements from digikey or mouser. Even a fragment of a part number can help you in your search for a replacement chip (black boxes). Another X24 owner may be able to help you with identifying these chips if the numbers have been obscured. The small boxes are probably resistors.

Hope this helps.

[dmdsoftware]

Looks like the power switching chip. Don't know the part number, but make sure you take a close look on the reverse side of the board too. Usually when these chips burn out, they do damage on both sides of the board.

What causes it? An eletrical short caused by the user - i.e. spilling a lot of coke on the keyboard, or plugging in the wrong AC adapter.

I've repaired an X21 with the same problem - it's not a real easy job.

[Quattro]

thanks for the tips. I just need to ID the chip somehow.

[Quattro]

UPDATE:

The burnt chip has the marking '4800' on the very top, anything below this is burnt through.

On the other side of the board, i noticed a chip with the markings:

4800
TU
L22B

Both chips look exactly the same, 4 pins on either side, rectangle.

Can't find anything on Mouser or Digikey

Anyone have a parts laptop/motherboard? Broken laptop anyone wants to sell? This tiny chip is disabling quite a nice laptop (1.2ghz), and i'd hate to give up on it.

UPDATE2: I found a chip on Mouser.com with 4800 in the part number, made by Fairchild Semiconductor. A quick google search for "Fairchild IBM" shows the two companies have worked together. Getting closer.

http://www.mouser.com/?Ne=500&handler=d ... &Ns=SField

[bhtooefr]

Nope... those are 16-pin chips...

You might want to ask on CPU-Museum.de/forum... they're pretty good with chip identification...

[Quattro]

Thanks for the link. Seems to be a good site.

[dmdsoftware]

I just received an X24 motherboard yesterday.

The chip is

4800
AH
W258

I'm looking for an LCD. If you deem your mission a failure, I could sure use your LCD.

[Quattro]

Thanks for the ID. I will sell you the LCD cheap if i can't get the board working. thanks again!

By any chance can you describe or photograph the logo on that chip?

[dmdsoftware]

Thanks for the ID. I will sell you the LCD cheap if i can't get the board working. thanks again!

By any chance can you describe or photograph the logo on that chip?

I will try to take a picture tonight. The writing is real small and I had a hard time reading it. It may or may not get picked up by my camera, but it will be worth a try.

[Quattro]

I found the part at Mouser.com thanks to the kind people at CPU-Museum.de and these Thinkpad forums. Repair is worth a try at only $1.44.

http://www.mouser.com/index.cfm?&handle ... 0&crc=true

Siliconix logo, now called Vishay Siliconix.

Si4800 MOSFET.

Datasheet:

http://www.vishay.com/doc?70856[/url]