Radio Shack TRS-80 Model 100

The TRS-80 Model 100 is a Tandy Corporation 8-bit portable computer released in 1983. It is actually a rebranded Kyotronic 85 designed and produced by Kyocera for the Japanese computer market. It was a very successful model for Tandy, selling over 6 million units, no doubt due to its compact & portable size, excellent keyboard, built-in modem, and the fact that it runs on standard AA batteries.

For more information, see this article's corresponding Wikipedia page: Device.

This device is in the WorkNeeded:OriginalParts category because it was flagged as missing information on the original parts. It may have replacement parts listed but those cannot be assumed to be identical to the originals. If you have a list of the original parts, please feel free to add them by copying the relevant table from EditorsToolbox:Tables

This device is in the WorkNeeded:General category because it was flagged as missing general information about the device. The information may be incomplete, using default text, or inaccurate and should be verified with external sources if possible. If you can add or correct information on this page, please feel free to edit it and do so.

TRS-80 Model 100

Preliminary Information
Release Year	1983
Leak Risk	Medium-High
Batteries	Four (4) AA, 1 NiCd (3.3v)
Mounting Technology	Through Hole
Capacitor Types	Aluminum Electrolytic, Tantalum, Ceramic, Polymer
Destructive Entry	No

This is a template page for creating new pages for devices, troubleshooting them, part lists, and other repair info.

Known Issues

Leaking NiCd Battery

This is a very typical issue on the Model 100 and its variants. The NiCd batteries, if still installed, are very likely to have leaked after nearly 40 years (as of 2022). The originally installed NiCd is usually a Yasua 3-51FT-A 3.3 volt, at least in USA variants. It is soldered by its legs to the motherboard, 1 leg on each side of the battery. When it leaks, it tends to spread across the board and infect other components while corrupting the board screening and etchings. These batteries are surprisingly good quality, however, and some of them still function normally all these years later. Either way, to avoid damage to the circuit board, any original NiCd battery in the Model 100 should be immediately replaced.

Causes

• Age. These batteries were not meant to survive beyond a few years. Most owners of Model 100s never replaced these batteries, as the skill needed to do so would have been beyond that of a normal user.
• Long-term exposure to humidity or higher than room temperatures would most certainly hasten the breakdown of the battery's shell and internal chemical composition.

Solution

• While it is possible for the Model 100's original NiCd batteries to still work seemingly fine all these years later, they should be replaced immediately.

TBD: the process of replacing the NiCd.

Won't Power On - Low Battery Light Flickers

With fresh batteries or

Causes

• Usually leaking capacitors

Solutions

• TBD: replacing the caps

Symptom or Problem Encountered

Causes

• Description of cause

Solutions

• Solution to the problem

Disassembly Notes

Warnings or tips to disassemble the device

TBD: go through a photo-based teardown.

Original Parts

Basic PCB Name (call out all the variants)

Note model numbers and board revisions here

Capacitor Specifications and Footprint Information

RefDes	Qty	Capacitance	Voltage	Mount	Diameter/Size	Height	Lead Spacing	Temp	Type	Brand	Series
		0 µF						0 °C

Replacement Parts

Basic PCB Name (call out all the variants)

Capacitors

RefDes	Qty	Compatible Part Number	Order Links
			Digikey

If parts are not available or different selection is preferred, you can use the values in the Original Parts section to perform a parametric search.

Kits

• Digikey BOM: https://www.digikey.com/

Related Links

• Videos or other things that might be helpful to check out