Toshiba T1200 Power Supply

Revision 1.3 now available!

Changes - A crowbar circuit on the 5V rails to protect against over-voltage in case the 5V regulator fails short-circuit. The regulators are supposed to protect against this, but I have had to source the item from lesser-known brands because of supply problems and so added some extra piece of mind.

The Toshiba T1200 was one of the first laptop computers and was sold in 1987. The power supply was quite advanced for the time offering voltage monitoring, HDD power management, battery power and charging. However, the supply was also notoriously prone to failure mostly through capacitors leaking and damaging the multi-layer board.

After re-capping my own machine, and replacing transistors and diodes, I was never able to get the original power supply to work reliably and so decided to re-design a modern replacement.

This is a replacement power supply board for the Toshiba T1200 laptop. It is only a bare-bones design to get the system to boot and does NOT offer any of the "advanced" features mentioned above. It simply provides the voltage rails required to run the system.

Please note that it will NOT work with the T1200XE.

Installation and Use

This power supply requires 12V DC, like the original, with a centre-positive DC barrel jack connector. However by default I have chosen to use a smaller, more modern, connector size. Please take note of the different DC connector size option depending on whether you intend to use the original power brick supplied with the machine, or a more modern version. The footprint and pinout for these connectors are the same and so you can swap them over with some basic soldering skills. I have also been able to power the device using a USB-C PD to 12V adapter.

I have not made a video detailing the installation process yet, however there are plenty of "teardown" videos available, and there are not really any tricks or "gotchas".

Warning

While I have designed and tested this device as best as I know how, I am only a hobbyist and NOT an engineer. I happily use this on my own personal machine but I advise that everybody read the documentation and make their own decision on whether they are happy to entrust their precious vintage Toshiba with my work.

Documentation and License

This product was designed using EasyEDA, and manufactured by JLCPCB. The design is open source and released under GPL 3.0; please feel free to make, modify, and sell your own versions.

Have a look at the EasyEDA project and GitHub links below for full documentation.