TRS-80 PC-8
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| Tandy PC-8 (photograph Jcassara86, CC BY-SA 4.0) | |
| Specifications | |
|---|---|
| Manufacturer | Sharp, for Radio Shack (Tandy Corporation) |
| Type | Pocket computer |
| Released | 1987 |
| Intro price | US$59.95 |
| CPU | Sharp SC61720D03, 4-bit CMOS |
| Memory | 2 KB (HM6116), 1,278 bytes for programs and data |
| Storage | Cassette, through the PC-3's 26-3591 printer/cassette interface |
| Display | 16-character 5 × 7 dot-matrix LCD (LF7133E) |
| Sound | — |
| ROM | 17 KB inside the CPU |
| Power | Two CR2032 lithium cells (6 V) |
| Dimensions | 135 × 70 × 9.5 mm |
| Weight | 95 g with cells |
| OS / Firmware | BASIC |
| Model no. | 26-3655 |
The TRS-80 PC-8, sold as the Tandy Pocket Computer PC-8, catalogue number 26-3655, is the last of Tandy's pocket computers, introduced in 1987. It is a rebadged Sharp PC-1246, a low-cost member of Sharp's PC-1250 family.[1][2] A single Sharp SC61720D03 4-bit CMOS processor holds the BASIC interpreter and drives the 16-character display, and one HM6116 chip provides 2 KB of RAM, of which 1,278 bytes are free for programs. It runs from two CR2032 lithium cells and came in a hard case.[2][1]
History
[edit | edit source]Sharp introduced the PC-1245 and the PC-1246 in 1983 as low-cost versions of the PC-1250; Tandy did not sell the PC-1246 until 1987, as the replacement for the TRS-80 PC-3. Kaiser notes that its BASIC is fully compatible with the PC-3's, so programs that fit the smaller screen run unchanged, and that it lasted less than a year on sale.[1] The Pocket Museum gives the PC-8's year as 1986.[3]
The PC-8 was the only Tandy pocket computer with a rigid hard case, and Kaiser describes it as the lightest and most durable of the line.[1]
Hardware
[edit | edit source]| Ref. | Part | Function |
|---|---|---|
| LSI1 | SC61720D03 | 100-pin 4-bit CPU with 17 KB of ROM and the display driver on the chip |
| IC1 | HM6116 | 2 KB static RAM |
| X1 | 1024 kHz crystal | System clock |
| D1–D3 | DAN202 | Diodes: D1 in the supply, D2 and D3 on the connector |
| TR1 | 2SA1179 | Transistor in the LCD drive voltage circuit |
| VR | 20 kΩ variable resistor | LCD contrast |
| – | LF7133E | LCD, connected to the board through a rubber connector |
| C4 | 22 µF 6.3 V | The only electrolytic capacitor |
Sharp's manual describes the SC61720D03 as a 100-pin, 4-bit processor with no internal RAM, which runs its programs from the external RAM.[2] The PC-1247, which Tandy did not sell, has its own version of the board with a second 2 KB of RAM (3,326 bytes free) and a buzzer.[2] Sharp's specification gives 17.4 KB of system ROM; Kaiser and the Pocket Museum give 18 KB.[2][1][3]
Power
[edit | edit source]Sharp specifies 6 V from two CR2032 lithium cells, a consumption of 0.07 W, and about 1,000 hours of operation showing a number on the display at 20 °C, or about 2.4 months at one hour of use a day. The computer switches itself off after about 11 minutes.[2] On the schematic the cells feed the supply through a 22 Ω resistor (R1) and the DAN202 diode D1, with C4 across it.[2]
Interface
[edit | edit source]The PC-8 has the 11-pin interface of the PC-1250 family and takes the PC-3's peripherals, including Tandy's 26-3591 printer and cassette interface, without adaptation.[1] Sharp lists its own CE-124, CE-125, CE-126P and CE-152 as options.[2] The schematic labels the port an 11-pin connector; the parts list orders it as a 12-pin connector part (QCNCW1306CC1B).[2]
Documentation
[edit | edit source]- TRS-80 PC-8 Documentation describes Sharp's PC-1246/PC-1247 service manual, hosted here.
Repair guides
[edit | edit source]- TRS-80 PC-8 General Maintenance – cells, reset, keyboard and opening the case
- TRS-80 PC-8 Troubleshooting Guide – Sharp's current, memory and auto power-off checks
- TRS-80 PC-8 Capacitor Replacement Guide – the single electrolytic, C4
Related pages
[edit | edit source]- TRS-80 Pocket Computer – the whole Tandy pocket computer line
- TRS-80 PC-3 – the Sharp PC-1250/1251-based model whose peripherals the PC-8 shares
- Battery Explosion, Capacitor or Corrosion Damage
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Cameron Kaiser, "Tandy Radio Shack Pocket Computer PC-1, PC-3, PC-8", Floodgap Retrobits, Tandy! Pocket! Mania!. Retrieved 2026-10-21. PC-8 section: 26-3655, introduced 1987 as the Sharp PC-1246; SC61720D03 4-bit CMOS CPU; 16-character LCD; 18 KB ROM; 1,278 of 2,048 bytes free; 135 × 70 × 9.5 mm, 95 g; the PC-1245 and PC-1246 as 1983 low-cost versions of the PC-1250; the hard case; the 11-pin I/O port shared with the PC-125x peripherals and the PC-3's options; US$59.95; on sale for less than a year.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Sharp Corporation, Service Manual: PC-1246, PC-1247, code 00ZPC1247SM/E, December 1984. Hosted as File:Sharp PC-1246 PC-1247 Service Manual.pdf. Key layout and specifications p. 1; memory map p. 1; CPU signal description p. 2; PC-1246 circuit diagram pp. 3–4; parts and signal positions pp. 5–6; check items and cautions p. 11; parts list p. 12; exploded view p. 13.
- ↑ 3.0 3.1 Pocket Museum, "The Tandy PC-8 computer (26-3655)" and "The Sharp PC-1246 computer". Retrieved 2026-10-21. Specification table: 2 KB RAM, 1,278 bytes available, 18 KB ROM, 4-bit CMOS CPU, one line of 16 characters, 135 × 70 × 10 mm, 95 g, two CR2032 cells, year 1986; options 26-3591 printer and tape interface.