IBM T23 not booting up

[elmasduro]

Hi everybody, i have an IBM T23 laptop and it is not booting correctly. when i turn it on, the fan surges, there is no video at all in the screen. I tried with an external monitor and no video. I took out the memory ram but nothing. this happen both with battery or with ac adapter plug in. when i turn on the laptop, i could here the fan like forcing itself.

I read some articles here in this forum and inductors are mentioned. i am not familiar with inductors.
can somebody help me to diagnose this problem? if you guys think inductors might be the problem, can you tell me how do i take them out so i can re-solder them? where do i buy them? what else should i look for?

Thanks for your help. all comments are welcome.

[rkawakami]

Welcome to thinkpads.com!

The fan surging is the symptom of a disconnected inductor. There's many threads here which talk about the problem, the best of which is the "sticky" near the top of the T2x/T30 forum:

http://forum.thinkpads.com/viewtopic.php?f=28&t=21979

Inductors in the T23 which lead to this power problem are the ones seen in this scan at locations E8 and D9:

http://www.kawakami-ca.com/ibm_t2x/mobo ... legend.jpg

They are the black "squares" with a circlular indentation on the top. In order to get at them, you have to take the entire motherboard out of the bottom chassis. This is done by following the directions in the T2x Hardware Maintenance Manual:

http://www-307.ibm.com/pc/support/site. ... UYM3F.html

This is a fairly involved process but one which can be done if you take your time and keep good track of the pieces being removed (especially the screws). Once the board is out, you may find that the inductors appear to be connected to the board but if you take a fingernail and lift the edge or corner of the inductor, it will pop right off the board. Be sure to cover the inductor with your other hand or shield it from flying across the room! You generally don't have to worry about buying a replacement since the inductor is usually still (partially) connected to the motherboard or it's sitting inside the base. On rare occasions, it will have fallen off the board AND exited the system. In those cases, you can either buy one from places like Digikey.com or Mouser.com - part numbers are listed below or ask around here in the Marketplace and see if anybody has spares or buy a cheap T23 off of eBay (and hope) that the inductors are in that system.

Once you've figured out which ones are loose, clean the bottom of the two metal tabs (the parts which sits on the motherboard). You typically will find that they are coated with a black film but it can be removed by gently scraping it off with a flat-bladed screwdriver. It should look like copper or silver at that point. I also remove all of the solder that's on the pads on the motherboard by using "solder wick"; basically braided wire infused with flux that you place over the pad and heat with a soldering iron. The solder melts and gets wicked up into the braided wire. Then it's a simple matter of putting a tiny amount of solder on both pads of the inductor. Place the inductor over the pads on the motherboard and heat up one side. The metal lead of the inductor bends around to the side so you can apply the soldering iron tip along the side and get the solder to melt after about 5-10 seconds. I should mention at this point that you should use a soldering iron rated at no more than 20-25 watts otherwise you will be applying too much heat. When one side of the inductor is soldered down, heat up the other lead. You might have to alternate sides to finally get the inductor to bond with the board; in most cases you aren't going to get the inductor to sit perfectly flat against the board either.

Both inductors are made by Sumida and are of the CDRH104R series. The one at E8 is a CDRH104RNP-2R5 and is rated at 2.5uH. The one at D9 is a CDRH

ref: http://search.digikey.com/scripts/DkSea ... -1432-1-ND (2.5uH)
ref: http://search.digikey.com/scripts/DkSea ... -1281-1-ND (5.2uH - not stock at this time)
ref: plug in "CDRH104RNP-2R5NC" and "CDRH104RNP-5R2NC" in the search box at http://www.mouser.com/