Josh: Create Psion page set: researched from Psion manuals, service documentation and community repair sources

2026-09-08T23:00:21Z

Create Psion page set: researched from Psion manuals, service documentation and community repair sources

New page

<templatestyles src="Template:StyledTable/styles.css" />
[[File:Psion Series 5.jpg|thumb|420px|A Series 5. This is the one Psion for which the factory service manual survives, complete with the Final Test fault-code table — which is effectively Psion's own list of what they expected to fail.]]

Fault-finding for the '''[[Psion Series 5]]''' (1997).

The Series 5 shares its mechanics with the [[Psion Series 5mx|5mx]], so '''the symptom table, the blind-backup procedure and the reset levels in the [[Psion Series 5mx Troubleshooting Guide]] apply here'''. What this page adds is the material that is genuinely Series 5-specific — and, because Psion's own service manual survives for this machine, a good deal of factory diagnostic detail.<ref name="sm">''Psion Series 5 Service Manual'', Psion Computers PLC, November 1997. Hosted on this wiki as [[:File:Psion Series 5 Service Manual (November 1997).pdf]]. Source for the circuit description, reset behaviour, clock frequencies, LCD and digitiser interfaces, standby currents, board-level repair recommendation, daughter PCB advice, and the Final Test explanations and Fail Ticket codes.</ref>

== ⚠️ Before you start ==

* '''Back up first.''' Removing both the main cells and the lithium cell without external power '''erases the internal memory'''.<ref name="sm" />
* '''Use the stylus, not a metal tool''', to lever out the lithium cell.<ref name="sm" />
* '''Do not bend the LCD module or the daughter PCB''' — both fracture.<ref name="sm" />
* Anti-static discipline throughout.<ref name="sm" />

== Step 1: which machine is it? ==

'''Confirm you have a Series 5 and not a 5mx before ordering any part.''' They look alike and their '''mainboards, screens and screen ribbon cables are different and not interchangeable'''.<ref name="wp">[https://en.wikipedia.org/wiki/Psion_Series_5 "Psion Series 5"], Wikipedia. Source for the statement that Series 5 and 5mx internals are not interchangeable, and the CPU and RAM differences.</ref><ref name="r3uk">David Savery, [https://www.r3uk.com/index.php/tech-tips/34-disassembly-guides/9-psion-series-5mx-disassembly-and-screen-cable-repair "Psion Series 5MX disassembly and screen cable repair"], R3UK, 2004. Source for the ribbon failure mechanism, the partial-open workaround and the statement that the 5mx uses a different screen ribbon.</ref>

A Series 5 has a '''CL-PS7110 at 18.432 MHz''' with '''4 or 8 MB'''; a 5mx has Psion's '''Windermere''' SoC at 36 MHz with '''8 or 16 MB'''.<ref name="wp" /><ref name="wuffs">Ash Wolf (Ninji), [https://wuffs.org/blog/building-a-psion-emulator "\"16 Shades of Grey\" — Building a Psion/EPOC32 Emulator"], 27 December 2019. Source for the CL-PS7110 / ARM710a and Windermere / ARM710T identifications.</ref>

== Step 2: which reset happened? ==

The Series 5 has two, and they have opposite consequences:<ref name="sm" />

{| class="wikitable styled-table" style="width:100%; text-align:left;"
|+'''Resets'''<ref name="sm" />
! Reset !! Mechanism !! Effect
|-
| '''User reset (warm)''' || A switch that '''forms part of the lithium backup battery's negative contact'''. Reached by opening the backup battery cover and using a pointed instrument || Vectors the CPU to a warm restart. '''All user data should be recovered.'''
|-
| '''Power-On Reset (cold)''' || A '''Ricoh RN5VLR20AA''' voltage detector fires when VDD crosses '''2.0 V ± 2.5 %'''. An RC network stretches the pulse || '''Erases all data held in volatile storage.''' Indicates that all power was lost and re-applied.
|}

'''A machine that resets constantly may have a bent lithium contact.''' Psion list "lithium reset contact permanently down" as a fault cause, with the fix being to '''bend the contact away from the PCB'''.<ref name="sm" /> The reset line is held inactive high by pull-up R1, with capacitor C113 providing noise bypass against inadvertent resets from ESD — so a machine resetting on static is a related symptom.<ref name="sm" />

== Step 3: measure the standby current ==

Psion's own figures, measured with the processor asleep at 2.75 V:<ref name="sm" />

{| class="wikitable styled-table" style="width:50%; text-align:left;"
! Model !! Standby current
|-
| 4 MB || '''1.50 mA'''
|-
| 8 MB || '''2.10 mA'''
|}

If a machine is well above that, Psion's own Final Test attributed excessive standby current to '''the DRAM on the PCB, dry joints and floating inputs, and shorts caused by metallisation of the plastics onto the PCB'''.<ref name="sm" /> The case mouldings are metallised for EMC, and flakes of that plating shorting onto the board is a real, factory-recognised failure mode.

== Step 4: the Final Test fault codes ==

Psion's factory tester printed a numeric Fail Ticket for each failure. Even without the rig, this is '''Psion's own fault-to-assembly map''' — the most useful single diagnostic table for the machine.<ref name="sm" />

{| class="wikitable styled-table" style="width:100%; text-align:left;"
|+'''Series 5 Final Test Fail Ticket codes'''<ref name="sm" />
! Code !! Test !! What to check !! Assembly
|-
| '''01''' || Too much current || — || PCB
|-
| '''03''' || No response to the wake-up signal (DSR), or did not boot into the test program (no DTR) || Battery module contacting the positive contact; the unit's battery spring clip present; expansion connector DSR and DTR || PCB battery spring; PCB expansion connector
|-
| '''04''' || Failed Tx/Rx communication || CompactFlash fully inserted; CF door fully shut and the device detected; ROM board connections; expansion connector Tx/Rx; '''lithium reset contact permanently down''' || Plastics cam operator and PCB door switch; PCB ROM board connector; PCB expansion connector; '''bend the lithium contact away from the PCB'''
|-
| '''06''' || Language / RAM size || Test program setup || Wrong unit build
|-
| '''07''' || Standby current out of limits || DRAM on PCB; dry joints, floating inputs; shorts from metallisation of plastics onto the PCB || PCB; dictaphone plastics
|-
| '''08, 10''' || LCD connector || — || LCD
|-
| '''09''' || Backlight connector || — || Backlight
|-
| '''11''' || Keyboard connector, keys || — || Keyboard
|-
| '''12''' || Expansion connector Tx, Rx || — || PCB expansion connector
|-
| '''13''' || Expansion connector RTS, DTR, CTS, DSR, DCD || — || PCB expansion connector
|-
| '''14''' || IrDA not blocked || — || PCB IrDA devices
|-
| '''15''' || Lithium cell in socket; dry joints on the lithium contacts || — || PCB; lithium contacts
|-
| '''16''' || DC jack lead properly inserted || — || PCB DC jack socket
|-
| '''17''' || Expansion connector Vin2+ and ground || — || PCB expansion connector
|-
| '''18''' || Expansion connector shield || — || PCB expansion connector
|-
| '''19''' || Expansion connector Vpc || — || PCB expansion connector
|-
| '''22''' || Unit properly seated, speaker fitted correctly || — || Speaker
|-
| '''23''' || Unit properly seated, microphone fitted || — || PCB microphone
|-
| '''24''' || Case switch stuck open || — || PCB case switch
|-
| '''25''' || Digitiser connections || — || Digitiser
|-
| '''26''' || Action of the dictaphone buttons || — || Plastics; PCB dictaphone switches
|-
| '''27''' || Case switch stuck closed || — || PCB case switch
|-
| '''28''' || Dictaphone status LED || — || PCB status LED
|-
| '''29''' || Plastic cam operator of the CompactFlash door || — || Plastics; PCB CF door switch
|-
| '''31''' || Lithium and CompactFlash removed || — || PCB
|-
| '''33''' || ROM board devices || Test program setup || Wrong unit build
|}

=== What the test tells you about the CompactFlash slot ===

Psion note that the CF interface is '''implied to be working if the unit boots into test mode''' — there is no separate check of every line, because booting from CompactFlash requires good conformance anyway.<ref name="sm" />

Crucially: '''to boot successfully the CompactFlash door switch must be closed and the card properly inserted'''. If the door switch does not operate, the test program will not boot at all. Psion's own field check is to '''select drive D: in the System window and open and close the door to see whether the disk is detected'''.<ref name="sm" />

== Step 5: the daughter PCB ==

'''Certain intermittent faults are caused by dry or faulty joints on the ROM daughter PCB.''' Psion recommend swapping it early as a quick way to confirm.<ref name="sm" />

Two conditions:

* '''Do not bend the daughter PCB''' during removal — it is prone to fracture.<ref name="sm" />
* '''A replacement must be the same OS build number and language.''' Check with '''Ctrl+H''' in the System screen.<ref name="sm" />

== Step 6: display faults ==

The LCD needs its rails '''sequenced''' so that no residual DC is left across the panel; DC causes the liquid crystal to drift and eventually damages its polarisation permanently.<ref name="sm" /> That is why the display is re-initialised at every power-up, and why a half-powered machine can show odd artefacts that are not in themselves a panel fault.

{| class="wikitable styled-table" style="width:100%; text-align:left;"
! Symptom !! Cause !! Action
|-
| '''Horizontal lines across the display''' || '''Cracked screen ribbon''' — the dominant fault on this platform || Replace the cable. '''The Series 5 cable is not the same as the 5mx's.''' See [[Psion Series 5 Hinge Cable Repair]].<ref name="r3uk" />
|-
| '''Display works only when the lid is part-open''' || Cracked ribbon, not yet fully open circuit || Back up immediately, then replace the cable.<ref name="r3uk" />
|-
| '''Missing rows or columns in a test pattern''' || LCD connector or the panel || Psion's own display test checks for exactly this.<ref name="sm" />
|-
| '''Backlight dead''' || Backlight connector, or the backlight itself || Fail code 09. Psion warn the backlight is '''delicate and prone to damage during servicing'''.<ref name="sm" />
|-
| '''Touchscreen inaccurate''' || Calibration lost || Factory calibration is stored in non-volatile memory and '''is lost if the unit loses all power'''. Recalibrate through the OS.<ref name="sm" />
|-
| '''Touchscreen dead in one axis''' || One of the four digitiser connections open || Fail code 25.<ref name="sm" />
|}

== Everything else ==

For the blind-backup procedure, the reset levels, the case-open microswitch, the stylus catch, the battery-current check and the general symptom table, see '''[[Psion Series 5mx Troubleshooting Guide]]''' — it is the same platform.

== Related pages ==

* [[Psion Series 5]] · [[Psion Series 5 General Maintenance]] · [[Psion Series 5 Hinge Cable Repair]]
* [[Psion Series 5 Service Manual]]
* [[Psion Series 5mx Troubleshooting Guide]] — the shared platform diagnostics
* [[Battery Explosion, Capacitor or Corrosion Damage]] · [[Recommended Tools]]

== References ==

<references />

{{Navbox-Psion}}

[[Category:Psion]]
[[Category:Troubleshooting Guides]]

Psion Series 5 Troubleshooting Guide - Revision history

Josh: Create Psion page set: researched from Psion manuals, service documentation and community repair sources