Jump to content

Psion Series 5mx Pro Troubleshooting Guide

From RetroTechCollection
Psion Series 5mx Pro
Psion Series 5mx Pro

Troubleshooting guide for the Psion Series 5mx Pro. The Pro is a Psion Series 5mx whose operating system loads from a CompactFlash card instead of ROM.[1] Hardware faults are those of the 5mx and are covered in the Psion Series 5mx Troubleshooting Guide. The faults below are the boot problems peculiar to the Pro. Check them first: a Pro that has lost its operating system looks like a dead machine.

Preliminary checks

[edit | edit source]

With no operating system in RAM and no usable card, the Pro's boot loader shows a German prompt, "Bitte CompactFlash-Card einlegen oder serielle Verbindung herstellen" ("insert a CompactFlash card or make a serial connection"), and waits for a card or for a YMODEM transfer over the serial port.[2][1] A machine showing this prompt is working.

Pro boot symptoms
Symptom Probable cause Action
German prompt asking for a CompactFlash card or serial connection No operating system loaded. Normal after any total loss of power Insert a card with Sys$rom.bin in its root, or send the file by YMODEM.[2][1]
Prompt persists with the card inserted File missing, misnamed or not in the root of the card; card too large; CompactFlash door switch not closed Check the file name and location. Try a card of 512 MB or less. Check the door switch (next row).[1][2][3]
Card reads in a PC but not in the Psion CompactFlash door switch. Psion's factory test boots from CompactFlash only with the door switch closed and the card fully inserted Once the machine is running, select drive D: in the System screen, then open and close the door and watch for the card being detected.[3]
Boots once, then hangs Card, door switch, or a board fault such as corrosion Try a different card and check the door switch before condemning the board. Inspect the board for corrosion.[4]
User data gone after the batteries went flat Expected. RAM holds the operating system and user data, and both are lost when all power is removed Reload the operating system from the card and restore data from a backup.[2]

Recovering the operating system

[edit | edit source]

From a CompactFlash card

[edit | edit source]
  1. Copy Sys$rom.bin (about 10 MB) to the root of a CompactFlash card using a card reader.[1][5] If the file was downloaded under another name, rename it to exactly Sys$rom.bin.[2]
  2. With the Psion switched off, insert the card and close the door.
  3. Switch on. The boot loader loads the file into RAM and starts EPOC.
  4. Reset preferences and Control Panel settings, then restore user data from a PC backup over the serial cable.[2]

A Consuming Experience found a 512 MB SanDisk card worked on the 5mx and a 1 GB card did not.[2]

Psion shipped German operating system builds 1.05 (265), 1.05 (273) and 1.05 (319) for the Pro and no English build. English images built from the standard 5mx ROM exist, and one ran on a German Pro in the Consuming Experience account.[1][2]

Over the serial port

[edit | edit source]

At the prompt the boot loader also accepts the operating system over RS-232 using YMODEM.[1] Connect a serial cable (a USB-serial adapter works) and send Sys$rom.bin from a terminal program that supports YMODEM. The serial load goes into RAM only, so the next total power loss needs it again; putting the file on a card is the lasting fix.

Typing about at the boot loader prompt shows the boot loader version. Versions 1.08 and 1.09 are known.[6][1]

Hardware faults

[edit | edit source]

Once it has booted, the Pro behaves as a 5mx. The Psion Series 5mx Troubleshooting Guide covers:

  • horizontal lines or a blank screen from a cracked screen ribbon cable
  • a lid that will not open or shut properly, from broken hinge-wire hooks (see Psion Series 5mx Hinge Repair)
  • a machine that will not switch on or off with the lid
  • high battery drain
  • a stylus that will not stay in its slot
  • Psion's Final Test fault codes

Parts

[edit | edit source]

A 5mx Pro screen assembly has been fitted to a standard 5mx in a documented repair, so a Pro with a dead board is a source of screen parts for a 5mx.[4]

[edit | edit source]

References

[edit | edit source]
  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Bs0Dd, "Psion-ROM: Stock / Patched / upgraded ROM files for old Psion devices", GitHub, README section "Psion Series 5mx PRO". Retrieved 2026-09-30.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Improbulus, "Psion 5mx & Psion 5mx Pro tips: sys$rom.bin & operating system installation etc", A Consuming Experience, June 2008. Retrieved 2026-09-30.
  3. ↑ 3.0 3.1 Psion Series 5 Service Manual, Psion Computers PLC, November 1997, PDF p. 43 (final test, CompactFlash). Hosted on this wiki: File:Psion Series 5 Service Manual (November 1997).pdf. Written for the Series 5; the 5mx shares the door switch arrangement.
  4. ↑ 4.0 4.1 "Repairing a Psion 5mx handheld computer to add to my collection", Point in the Cloud, 13 October 2025. Retrieved 2026-09-30.
  5. ↑ Ash Wolf (Ninji), "'16 Shades of Grey' - Building a Psion/EPOC32 Emulator", 27 December 2019. Retrieved 2026-09-30.
  6. ↑ Bs0Dd, "Dumping Psion 5mx PRO BootLoader", Psion-ROM repository, GitHub. Retrieved 2026-09-30.


Retrieved from "https://retrotechwiki.com/index.php?title=Psion_Series_5mx_Pro_Troubleshooting_Guide&oldid=24303"