Toshiba T1100 - Modification for an AC Adapter of 12V DC
IMPORTANT: T1100, not the T1100 PLUS
BACKGROUND
If the 12V battery in your T1100 is faulty (will not charge sufficiently) or it is missing, then trying to use an AC adapter (the Toshiba specified 18V one) to power the T1100 will not work.
SCOPE OF THIS WEB PAGE
This web page provides instruction on how to modify a T1100 (T1100, not T1100 PLUS), so that a regulated AC adapter that produces +12V DC can be used to power the T1100.
NEGATIVE IMPACT
Note that as a result of this modification:
• The T1100's on/off switch will no longer turn off the T1100.
• No battery. It gets removed, and must not be reattached later (because we will be bypassing the battery charging circuitry).
REQUIREMENTS
1. That you have soldering skills.
2. An AC adapter that:
• Produces +12V DC.
• Is a regulated adapter; output is always +12V DC.
• Can supply up to 500 mA of current, a figure based on worst-case measurements that I made of the two T1100 units that I have.
• Has a DC connector that is the correct type and size for the T1100. See here.
• Has a DC connector where the center contact is the positive one.
WARNING
After this 12V modification, do not use the AC adapter provided with the T1100. Its output (18 to 24V DC) is way too high.
PROCEDURE
STEP 1: Open up the T1100.
STEP 2: Remove the motherboard.
STEP 3: On the motherboard's battery connector, solder a wire between the first two pins, as pictured at here. The wire needs to carry up to 500 mA of current. The advantage of placing the wire here, rather than on the motherboard's solder side, is that it prevents someone reattaching the battery later.
STEP 4: On the motherboard's solder side, cut the green trace pictured (cut) at here.
STEP 5: On the motherboard's solder side, solder an insulated wire per the photo at here. The wire needs to carry up to 500 mA of current.
STEP 6: Reassemble the T1100.
STEP 7: Attach a warning label to the T1100. An example is shown at here.
The T1100 can now be powered by connecting a regulated AC adapter of 12V DC output to the DC connector at the rear of the T1100.
About 5 seconds after connection, expect to see text (progress of a memory test) displayed on the LCD. If you don't see that, then make sure that the T1100's 'LCD/CRT' switch is in the 'LCD' position, and make sure that the 'LCD CONTRAST' control is set to its maximum setting.
After about a further 15 seconds (30 seconds if optional 256 KB RAM module fitted), expect to see the 'INT FDD' LED (top-right of keyboard) turn on momentarily as the T1100 attempts to boot from the diskette drive.