Psion Series 5
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| Psion Series 5 with 8 MB. Photo: Centre for Computing History | |
| Specifications | |
|---|---|
| Developer | Psion Computers PLC |
| Manufacturer | Psion Computers PLC |
| Type | Clamshell palmtop computer |
| Released | 1997 |
| Discontinued | Replaced by the Series 5mx in 1999 |
| CPU | Cirrus Logic CL-PS7110 (ARM 7100, ARM710a core) at 18.432 MHz |
| Memory | 6 MB ROM on a daughter board; 4 MB or 8 MB DRAM |
| Storage | Internal RAM disk; CompactFlash slot |
| Display | 640 × 240 passive-matrix LCD, 16 grey levels, backlit, with a resistive digitiser |
| Sound | Speaker, microphone and dictaphone buttons |
| Dimensions | 170 mm × 90 mm × 23 mm[1] |
| Weight | 354 g including batteries[1] |
| OS / Firmware | EPOC32 |
| Predecessor | Psion Series 3c |
| Successor | Psion Series 5mx |
The Psion Series 5 is a clamshell palmtop computer made by Psion Computers PLC and launched in 1997. It was Psion's first machine to run the 32-bit EPOC32 operating system on an ARM processor, and the first with the sliding-keyboard case in which the keyboard moves forward as the lid opens to counterbalance the screen.[2][3]
History
[edit | edit source]The Series 5 succeeded the Series 3 range; Psion did not make a Series 4.[2] The sliding case is covered by European patent EP 0766166 and was designed by Martin Riddiford of Therefore Design. A simplified version was later used on the Psion Revo.[2] Psion's November 1997 service manual lists 4 MB and 8 MB models.[3] The Psion Series 5mx replaced the Series 5 in 1999 with a faster processor, a clearer screen and updated software.[2]
Architecture and processor
[edit | edit source]The Series 5 is the first Psion product built on the ERA architecture around the ARM 7100 processor (IC1).[3] The ARM 7100 is the Cirrus Logic CL-PS7110, with an ARM710a core.[4] Its clock input is 3.6864 MHz ±50 ppm from crystal X2, multiplied internally by five to 18.432 MHz (54.2535 ns). The same 18.432 MHz is output as an expansion clock for the CompactFlash interface chip, ASIC12 (IC2).[3]
The machine has two resets:[3]
- The power-on (cold) reset comes from a Ricoh RN5VLR20AA voltage detector (IC4), which trips when VDD crosses 2.0 V ±2.5 %; an RC network stretches the pulse. A cold reset erases everything in volatile memory, and means that all power was lost and restored.
- The user (warm) reset is a switch built into the negative contact of the lithium backup cell, reached by opening the backup cell cover and using a pointed instrument. It is held high by R1, with C113 filtering noise so that static discharges do not cause resets. User data should survive a warm reset.
Memory and storage
[edit | edit source]The electronics are a main board and a ROM daughter board. The main board carries 4 MB or 8 MB of DRAM on a 32-bit bus; the daughter board carries 6 MB of ROM.[3] Psion built three daughter boards:[3]
| Board | Devices |
|---|---|
| ROM Board 01 | 3 × Flash |
| ROM Board 02 | 1 × ROM and 1 × Flash |
| ROM Board 03 | 2 × ROM |
A CompactFlash socket takes Psion Memory Disks and other CompactFlash cards. A switch detects the CompactFlash door.[3]
Display
[edit | edit source]The LCD is a 640 × 240 passive-matrix module with normally white pixels, driven directly by the ARM 7100, with a backlight.[3] It shows 16 grey levels.[2] A resistive digitiser sits over it: a glass lower plate and a hardened plastic upper plate with resistive ink on their inner faces, held apart by small bumps moulded into the plastic, and connected by a 22-way flat flexible cable.[3]
The LCD's supply rails are switched on and off in a fixed sequence so that no DC is left across the panel, because DC makes the liquid crystal drift and eventually damages its polarisation for good. The LCD logic supply draws about 2 mA; the main LCD voltage comes from a boost converter controlled by the ARM 7100, with a 4-bit DAC in its feedback path setting the contrast.[3]
Sound
[edit | edit source]A speaker and a microphone connect through a CODEC. Buttons on the case operate the dictaphone function, with a status LED.[3]
Input, output and expansion
[edit | edit source]The keyboard has 53 keys in a QWERTY layout, on a separate switch matrix that slides out as the screen opens. It connects to the main board through a 22-way flat flexible cable in a 22-way ZIF connector; 20 ways carry keys and the outer two are grounded to give the membrane a ground ring for ESD protection.[3]
The Series 5 has an RS-232 serial port on its expansion connector (the "Honda connector" in Psion's fault codes), an IrDA infrared port, and the CompactFlash slot.[3]
Power
[edit | edit source]The Series 5 runs from two AA alkaline cells, with a lithium backup cell and a 6 V DC input.[3] Typical battery life is 10–20 hours.[2] Psion's final test limits for standby current, measured at 2.75 V with the processor asleep, are 1.50 mA for the 4 MB model and 2.10 mA for the 8 MB model.[3]
Build variants
[edit | edit source]Psion's final test procedure lists 22 build part numbers, a 4 MB and an 8 MB build for each language, from 2900-0003-01 (4 MB English) through American, French, German, Italian, Spanish, Swedish, Norwegian, Danish and Finnish builds. The build is written to a serial EEPROM on the main board at final test, and the EEPROM is locked once the unit has passed.[3] The final test lead and dummy battery in the manual's connector diagram are labelled "PROTEA_TEST_LEAD" and "DUMMY PROTEA BATTERY".[3]
Series 5 and Series 5mx
[edit | edit source]The two look almost the same, but their main boards, screens and other internal parts are different and not interchangeable.[2] The screen ribbon cable is also a different part on each.[5]
| Series 5 (1997) | Series 5mx (1999) | |
|---|---|---|
| Processor | CL-PS7110, ARM710a core | Psion "Windermere", ARM710T core |
| Clock | 18.432 MHz | 36 MHz |
| RAM | 4 MB or 8 MB | 8 MB or 16 MB |
| Screen | 640 × 240 | 640 × 240, clearer panel |
Service manual and documentation
[edit | edit source]- Psion Series 5 Service Manual (PDF) – Psion's manual: circuit description, exploded views with part numbers, spares kits, disassembly and reassembly, and the final test procedure with its Fail Ticket fault codes.[3]
Known faults
[edit | edit source]The commonest failure is the screen ribbon cable, which cracks after years of opening and closing and gives lines across the display.[5] Psion's fault codes and the other faults are in the troubleshooting guide.
- Psion Series 5 Troubleshooting Guide
- Psion Series 5 General Maintenance
- Psion Series 5 Hinge Cable Repair
Related pages
[edit | edit source]- Psion Series 5 General Maintenance
- Psion Series 5 Troubleshooting Guide
- Psion Series 5 Hinge Cable Repair
- Psion Series 5 Service Manual
- Psion Series 5mx
- Psion Series 5mx Pro
- Psion Revo
- Battery Refurbishment
References
[edit | edit source]- ↑ 1.0 1.1 Centre for Computing History, "Psion Series 5 (Boxed)", specification: "Size 170 x 90 x 23mm, Weight 354g (12.5oz) with batteries". Retrieved 2026-10-01.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 "Psion Series 5", Wikipedia. Model history, the sliding case (European patent EP 0766166, designed by Martin Riddiford of Therefore Design), display, battery life, and the statement that the Series 5 and 5mx mainboards, screens and other internal parts are not interchangeable.
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 Psion Computers PLC, Series 5 Service Manual, November 1997. Hosted on this wiki as File:Psion Series 5 Service Manual (November 1997).pdf; see Psion Series 5 Service Manual. Introduction (PDF p. 4), circuit description (pp. 6–7), exploded views (pp. 9–15), spares kits (p. 16), disassembly (pp. 17–25), reassembly (pp. 26–27), final test procedure including build options, standby current and Fail Ticket codes (pp. 28–45).
- ↑ 4.0 4.1 Ash Wolf, "'16 Shades of Grey' – Building a Psion/EPOC32 Emulator", 27 December 2019. Processor identification for the Series 5 (CL-PS7110, ARM710a) and 5mx (Windermere, ARM710T).
- ↑ 5.0 5.1 David Savery, "Psion Series 5MX disassembly and screen cable repair", R3UK, 6 July 2004. The screen ribbon failure and the different ribbon on the Series 5.