Fixing an IBM T42 with Red Screen and Power Switching Mystery (In Vancouver)

On my way to meet my daughter, I picked up this IBM T42 Thinkpad on 21Jan2011 from a man wearing a security T-shirt at the entrance of his apartment. His listing had below:

KEYBOARD IS FINE, COMES WIT ORIGINAL IBM POWER ADAPTER.THE COMPUTER RUNS WHEN ATTACHED TO ANOTHER LCD MONITOR, NOT EXACTLY SURE WHAT IS WRONG WITH IT. THEN AGAIN I DON'T KNOW MUCH ABOUT COMPUTERS....HARDDRIVE MAY NOT WORK. LCD SCREEN WONT COME UP AS WELL, BUT THE IBM LOGO DOES. .

When I was home, I checked this T42. The palm rest and keyboard were heavily used and so shinny that needed replacement. The AC adapter had IBM logo on it but had smaller output power of 2.2A as compared to my other T42 which has 4.5A. The hard drive inside the laptop and the battery were missing. I emailed back the seller asking if he still had the hard drive. He replied that he did not and knew why his T42 was not working after seeing my email.

I needed the following parts to rebuild this T42:

1. Palm Rest with Touch Pad

I bought it online and they came from sellers with good ratings. Although the it was used, it is in good conditions.

2. LCD Screen

According to information from internet, the red screen was either due to inverter or black light problem. I installed a new inverter and found out that it was not the cause. I then bought a used LCD screen locally which turned out to have white spots. In eBay, I bought another used LCD screen of $35 with item description "pulled and tested Lcd screen from an ibm thinkpad".

3. Harddrive

A seller listed out 5 IDE harddrives that "The hard drives show up in windows through an external usb device but I cannot format the drives.- cannot run chkdsk or format." I asked if the hard drives have clicking sound for physical damage. The sellers replied no. I paid $65 for them and turned out that only one 40GB harddrive is good with no bad sectors. Two had bad sectors and 2 had clicking noise. The 40GB is too small. I bought another 60GB hard drive locally.

After getting all parts on 20April11, I borrowed an AC Adapter and a battery from another T42 to rebuild this T42. While assembling the parts, I cleaned up the T42 inside and outside. I ran the command fwrestor file=d:\backup to restore the backup files that I saved in previous T40/T41 fixing to create the IBM_PRELOAD partition in the T42 hard drive. At boot up, the blue key allowed me to use the 'Recover to factory contents' function to rebuild the T42. The factory contents do not have ATI and WiFi card drivers. I downloaded from IBM Web site and installed them. I installed XP SP2 further. The OS installation verified the DVD drive, Touch Pad, Keyboard, CPU, sound, video, cable network connection and wireless connection. I ran Youtube to check it further. When I put in the battery, the charging light did not come up. When I switched on the T42, the power source didn't switch to AC power until I removed the battery. When battery was in and the T42 was powered on, the battery got charged to 100%. For this problem, I could not flash the BIOS. To install SP2 which checks for AC power, I needed to remove the battery first. I had no idea on how to fix this power source issue. I shelved this T42 and googled a few months for clues.

On 3Sep2011, I used this T42 and the smaller 2.2A AC adapter to check some old batteries. The first battery was dead. The second battery had the charging light on but I remembered that this T42 was not able to charge until powered on. I powered on the T42. The power source was showing correctly. I tested further on the 2.2A AC adapter. Whenever the fan was running, the T42 beeped and changed to battery power until the fan stopped.

For the power detection issue, it seems that the T42 detected that 2.2A was low and kept in BIOS memory to use battery as priority whenever battery was plugged in. This could not be reset with the 4.5A AC adapter during my rebuild testing until I used the 2.2A AC adapter with a dead battery which the BIOS switched back to normal, using AC adapter as priority.

I used the 4.5A AC adapter to ran the BIOS flashing program. It passed the checking that requires both battery and AC power plugged in. Although the BIOS flashing program reported not necessary to update because the BIOS inside is the latest, it demonstrated that the power detection is normal again. The long outstanding mystery on power detection issue had finally been unveiled.

On 28Sep2011, this T42 has been picked up in Vancouver and serves again.