Tandy 1400LT and 1400HD: A tale of 2 Tandies.

Disclaimer: As an experiment, I used an LLM (Large Language Model) to generate some drafts of this blog post. I ended up rewriting most of it anyway, but I tried to leave it in a generic style of a YouTube Retro Channel...

Greetings vintage computer enthusiasts! Today, I have an exciting restoration project to share with you - the resurrection of not one, but two Tandy 1400 laptops. These devices were produced by Tandy/Radio Shack, a well-known computer vendor from the 70's and 80's.  Tandy, with Commodore, and Apple, was part of the 1977 trinity that started the micro-computer revolution. 

These pieces of computing history ended up in possession of family member, that, very kindly sent them to me, and I was thrilled to take on the challenge of restoring them.

Tandy 1400LT with 2 floppy drives. It has a 8088 compatible V20 CPU and 768 KB of RAM.

Tandy 1400HD with one floppy and one hard drive. It has a external floppy port, but no composite video out.

The Tandy 1400LT and its later sibbling, the 1400HD, were the two laptops that I received. Both devices have CGA graphics, but the 1400LT has a little-known feature that allows for artifact color output, providing a greater color range for games than the 4 horrible CGA colors. The feature disappeared as most PCs were used with digital-input monitors that did not display the artifact color. A year later, in 1988, Tandy released the very similar 1400FD and 1400HD models, that do not have this feature. 

When I received the devices, I found that, while they were very well packed, the 1400HD's bottom case was cracked and broken into many pieces, likely due to old age and brittle plastic. Luckily, the top half of the case was pristine. The 1400LT was in excellent condition.

Broken bottom case of the 14000HD. The black plastic is extremely brittle, and there were shards everywhere in the packaging.

Unfortunately, I have only one original power supply - the one for the 1400HD. However, it did not power up. When I attempted to use it on the 1400LT, I realized that it used a different voltage and reverse polarity. I was very lucky that the1400LT was not damaged, and I was able to find a suitable replacement PSU to bring it to life.

The 1400LT worked right away after I found a suitable power supply! I connected the composite video output to the monitor in the background in case the LCD was faulty.

Now, onto the restoration of the 1400HD. I spent a considerable amount of time collecting all the little plastic pieces and gluing them back together. I used superglue to quickly bond matching pieces and added large amounts of hot glue and epoxy on the inside to reinforce the structure. I also used JB WELD to patch missing holes and coat the outside cracks before sanding and spray painting black. The plastic was incredibly brittle, and some pieces even cracked just by moving it on the table.

This is what the 1400HD looked after gluing and sanding the major pieces.

There were some holes resulting from parts where the plastic shattered intro bits too small to glue.

And here is after using JB Weld to cover some missing holes. Meanwhile, some more parts of the case broke and had to be glued.

During disassembly, I accidentally ripped both keyboard membrane connectors and cut some conductors. I repaired the membranes by applying sticky tape to the non-conducting side to provide mechanical stability. Then, I painted over the cut traces with a specialized conducting paint that contains over 70% silver in an organic flexible solution. This paint is quite expensive, but only a small amount is needed, and I've used it for countless membrane repairs.

Broken keyboard ribbon cable.

The other broken ribbon cable. Here I had already reinforced the ripped membrane with transparent tape.

Ribbon keyboard patched with conductive silver paint. This paint consists of 70% silver in a polymer base that allows it to flex substantially and cover small gaps. I held the membrane with aluminium tape while the paint cures.

I powered the 1400HD using its power supply, and the screen backlight turned on, but the device did not boot or display any text on the screen. After digging for information online, I found that it does not boot if the internal PSU has bad capacitors. I replaced a few dozen electrolytic capacitors in the PSU and could smell the telltale fishy odor of capacitor juice. They had leaked all right. After replacing the capacitors, the computer started, and I was surprised to find that it even booted from the hard drive. I did not expect the hard drive to work after all these years.

Backlight is on, but no other sign of life. The keyboard is away, still waiting for the conductive paint to cure.

This is the disassembled PSU with lots of electrolytic capacitors, and fishy dried capacitor juice. 

Some of the replaced capacitors.

Now it boots, and the hard drive still works!
Here we can see Norton Commander and some of the contents.

Repaired and re-assembled Tandy 1400HD.

Overall, I was pleased with the restoration of these Tandy 1400 laptops. It was a challenging project, but I learned a lot and had fun bringing these vintage devices back to life. I hope that this blog post has inspired you to take on your own restoration project and appreciate the history of computing.

Now, a retro flashback to the earlier days of the Internet and the immortal words of Kompressor:

Remember, you do not use a Macintosh - instead, you use a Tandy. 

KOMPRESSOR break your glowstick.

KOMPRESSOR eat your candy.

Someone very special to me won a Tandy Technology Scholar Award.