Rainbow 100+
The Rainbow 100+ is the Rainbow PC100-B personal computer from Digital Equipment Corporation (DEC) with a Winchester hard disk fitted as standard. DEC's addendum to the Rainbow technical manual describes three versions of the Rainbow: the original PC100-A, the PC100-A with a hard disk upgrade kit, and the PC100-B; a PC100-B with an RD51 hard disk is the Rainbow 100+, and the PC100-B without one has every other part of it.[1] The addendum is dated December 1984 and the PC100-B print set July 1984.[6][7]
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| Rainbow 100+ with VR201 monitor and LK201 keyboard | |
| Specifications | |
|---|---|
| Manufacturer | Digital Equipment Corporation |
| Type | Personal computer |
| CPU | Intel 8088 and Zilog Z80A[1] |
| Memory | 128 KB, expandable to 896 KB[2] |
| Storage | RX50 dual 5.25-inch diskette drive (2 × 400 KB) and RD51 10 MB hard disk[1] |
| Display | VR201 30.5 cm (12 in) monochrome monitor[3] |
| Sound | — |
| Power | H7842-D switching supply, 142 W output[4] |
| Dimensions | System unit 16.5 × 48.3 × 36.3 cm (6.5 × 19 × 14.3 in)[4] |
| Weight | System unit 13.6 kg (30 lb)[4] |
| OS / Firmware | CP/M-86/80, Concurrent CP/M-86/80 or MS-DOS[5] |
| Predecessor | Rainbow 100 |
| Model no. | PC100-B |
Most of the Rainbow's hardware, its self-test and its service procedures are shared with the PC100-A and are covered on Rainbow 100 and its guides.
Differences from the PC100-A
edit| Item | PC100-A | PC100-B / 100+ |
|---|---|---|
| System module | 70-19974-00 | 70-19974-02 |
| ROMs | 3, 24 KB | 2, 32 KB |
| Memory on the system module | 64 KB | 128 KB |
| Memory options | 64 KB, 192 KB | 128 KB, 256 KB |
| Maximum memory | 256 KB | 896 KB |
| Power supply | H7842-A | H7842-D |
| Fan | AC | DC |
| Automatic memory sizing and bootstrap | No | Yes |
| Boot from hard disk | No | Yes |
| Enclosure | BA25-B | BA25-C |
System module
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The PC100-B system module, 70-19974-02, has two ROM sockets, E93 (ROM 0: bootstrap, diagnostics and VT100 emulation) and E94 (ROM 1: language ROM). Each takes a 16K × 8 or 32K × 8 part; jumpers W5 and W6 are removed for 16K × 8 ROMs and fitted for 32K × 8.[9][10] The 8088 is at E72, the Z80A at E69, the 256 × 4 NVM at E95, the screen RAM at E130 and E131 and the attribute RAM at E132 and E133.[9] Connectors J4 and J5 take either the extended communications option or the hard disk controller.[9]
DEC's spare part number for the PC100-B ROM 0 is 23-022E5-00. ROM 1 was supplied in language clusters, each with its own part number; cluster 1 is 23-020E5-00.[11]
Hard disk
editThe hard disk option, PC1XX-DA, is a controller module (54-16019) based on the Western Digital WD1010, with its drive cable (17-00427-01).[12] The controller's two 40-pin connectors plug into J4 and J5 on the system module and a 34-pin connector takes the drive cable.[13] The standard drive is the RD51:
| Item | Specification |
|---|---|
| Formatted capacity | 10 MB; 2.5 MB per surface |
| Geometry | 306 cylinders, 4 heads, 32 sectors of 256 bytes per track |
| Average access time | 85 ms |
| Transfer rate | 5 Mbit/s |
| Rotational speed | 3600 r/min ±1% |
| Power | +12 V ±5% at 1.6 A typical, 3.5 A at power-on; +5 V ±5% at 1.1 A typical |
| Dissipation | 25 W typical, 32 W maximum |
Power supply and fan
editThe H7842-D is an H7842-A redesigned to deliver more +5 V current for the hard disk, with a two-wire cable added to power a DC fan from +12 V. It is also fitted when a PC100-A is upgraded with the RCD50-BB (5 MB) or RCD51-BB (10 MB) hard disk kit.[15] DEC rates it at 142 W output and 237 W input, including 3 W for the fan.[4] Service information is on Rainbow 100+ General Maintenance.
Specifications
edit| Item | Specification |
|---|---|
| AC input | 90–128 V or 174–256 V rms, switch selectable; 47–63 Hz (57–63 Hz at high line) |
| Line current | 3.0 A at 115 V, 2.0 A at 230 V |
| Power | 237 W input at 142 W DC output |
| DC outputs | +5.1 V ±6%, +12.2 V ±6%, −12.0 V ±7% |
| Circuit protection | 4.0 A circuit breaker |
| Operating environment | 15–32 °C, 20–80% relative humidity |
Chapter 5 of the same addendum gives narrower input ranges for the H7842-D (104–128 V and 191–256 V) and a −12 V maximum load of 0.15 A, against 388 mA in chapter 1.[16][4]
Known problems
editThe PC100-B shares the H7842 supply family, the RX50 drive and the VR201 monitor with the PC100-A, so the faults on Rainbow 100 Troubleshooting Guide apply. Rob Jarratt, diagnosing his Rainbow 100A, borrowed the system module from a 100B to compare its behaviour on a logic analyser.[17] Hard disk messages and their causes are on Rainbow 100+ Troubleshooting Guide.
Documentation
edit- Rainbow Technical Manual Addendum for Models PC100-A, PC100-B, and Rainbow 100+, EK-RB100-TM-001: File:Rainbow Technical Manual Addendum PC100-A PC100-B and 100+ (EK-RB100-TM-001).pdf
- PC100-B print set, MP-01722-01: File:Rainbow 100 PC100-B Print Set (MP-01722-01).pdf
- User's Service Guide, EK-P100E-SV-001: File:Rainbow User's Service Guide (EK-P100E-SV-001).pdf
- Rainbow 100 Technical Manual, EK-PC100-TM-001, for the parts common to all models: File:Rainbow 100 Technical Manual (EK-PC100-TM-001).pdf
All are described on Rainbow 100 Documentation.
Related pages
editReferences
edit- ↑ 1.0 1.1 1.2 DEC, EK-RB100-TM-001, pp. 1-1 to 1-3. The three versions of the Rainbow and the units in each.
- ↑ 2.0 2.1 DEC, EK-RB100-TM-001, p. 1-4, Table 1-1, Rainbow Model Comparisons.
- ↑ DEC, EK-RB100-TM-001, p. 1-7, section 1.3.2. Monochrome monitor.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 DEC, EK-RB100-TM-001, pp. 1-6 to 1-7, sections 1.3 and 1.3.1. Environment, system unit and power supply specifications.
- ↑ DEC, EK-RB100-TM-001, p. 1-5. Features and operating systems.
- ↑ Digital Equipment Corporation, Rainbow Technical Manual Addendum for Models PC100-A, PC100-B, and Rainbow 100+, EK-RB100-TM-001, first edition, December 1984 (File:Rainbow Technical Manual Addendum PC100-A PC100-B and 100+ (EK-RB100-TM-001).pdf).
- ↑ Digital Equipment Corporation, PC100-B field maintenance print set, MP-01722-01, July 1984 (File:Rainbow 100 PC100-B Print Set (MP-01722-01).pdf).
- ↑ DEC, EK-RB100-TM-001, p. 1-1. BA25-C enclosure for the PC100-B and 100+, BA25-B for the PC100-A.
- ↑ 9.0 9.1 9.2 DEC, EK-RB100-TM-001, p. 3-4, Figure 3-2, PC100-B System Module Physical Layout.
- ↑ DEC, EK-RB100-TM-001, p. 3-16. ROM types and jumpers.
- ↑ Digital Equipment Corporation, User's Service Guide (Rainbow), EK-P100E-SV-001, April 1985, pp. 121 to 123, Table B-1 (File:Rainbow User's Service Guide (EK-P100E-SV-001).pdf).
- ↑ DEC, EK-RB100-TM-001, pp. 4-1 to 4-3. Winchester hard disk controller, PC1XX-DA option, WD1010.
- ↑ DEC, EK-RB100-TM-001, p. 4-29, section 4.6. Controller interface connectors.
- ↑ DEC, EK-RB100-TM-001, pp. 1-9 to 1-10, section 1.3.5. RD51 hard disk drive specifications.
- ↑ DEC, EK-RB100-TM-001, p. 5-1, section 5.1. H7842-D power supply and fan bracket 70-20816-01.
- ↑ DEC, EK-RB100-TM-001, pp. 5-7 to 5-8, section 5.5. H7842-D input and output specifications.
- ↑ Rob Jarratt, "Rainbow 100A Restoration", Rob's Old Computers, 29 July 2025, robs-old-computers.com.