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Psion Series 3c Troubleshooting Guide

From RetroTechCollection
A Series 3c. Electrically it is a 3a, so the shared diagnostics apply — but the SSD door sensing, the serial port and the case coating are its own.

Fault-finding for the Psion Series 3c (1996).

The full symptom table, the SIBO power states and the supply rail chart are in the Psion Series 3a Troubleshooting Guide, which applies to this machine unchanged. This page covers the 3c-specific faults.

⚠️ Before you start

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  • Back up first. RAM contents do not survive a battery removal.
  • Open both SSD doors before lifting the mainboard.
  • Anti-static precautions throughout.
  • Check the case coating before you start handling the machine. A tacky 3c will transfer onto tools and boards.

3c-specific symptoms

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Symptom Cause Action
SSD not recognised, intermittently or in one slot The 3c senses the doors with PCB tracks and a small metal connector on the door hinge. They tarnish Clean the tracks and the metal contact with isopropyl alcohol. Note this is not the 3mx's microswitch fault — the 3c has no door microswitches to break.[1]
3a serial cable will not fit Expected. The 3c serial port was changed and matches the Siena's Use a 3c/Siena cable. Travel Modem connections also differ between 3/3a and 3c/3mx.[2]
No backlight Often normal. Only later 3c models — mainly the US 2 MB machines — were backlit Confirm the model before treating it as a fault.[2]
Short battery life on a backlit 3c The backlight Check it is not being left on before investigating anything else.
Case tacky and glue-like The rubberised soft-touch coating degrading Strip it with high-purity isopropyl alcohol. Full method in Psion Series 3c General Maintenance.[3]
Infrared transfers fail Dirty or scratched IR window; misalignment Clean the window. IR needs line of sight and a sensible distance at both ends.
Eats batteries The battery lead — as on every Series 3 Re-seat the two-pin connector behind the batteries; rewire if the conductors are damaged.[4]
Vertical lines on the display Screen ribbon deterioration Replace the cable or fit a 3c donor lid. See Psion Series 3c Hinge Repair.[2]
Button bar dead Ribbon adrift from the lower PCB Push it home with a paperclip, lid half closed.[4]
Back edge crooked when opening Broken hidden hinge See Psion Series 3c Hinge Repair.

Everything else

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For the four SIBO power states, the supply rail chart (including the +16 V Vh rail that Flash SSD writing depends on), the full symptom table and the assessment of what is realistically repairable, see Psion Series 3a Troubleshooting Guide.

The 3c uses the same ASIC9 as the 3a, so the whole of that page's architecture-based diagnosis applies.

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References

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  1. ↑ Richard Zealley, "Psion Series 3mx SSD door microswitch repair", Retro Coding, 25 May 2020. Source for the difference between the 3c door-sensing tracks and the 3mx microswitches.
  2. ↑ 2.0 2.1 2.2 "Psion Series 3", Wikipedia. Source for the changed serial port, the Travel Modem connection difference, the backlight availability, the case redesign and the documented clamshell problems.
  3. ↑ Community discussion of the Psion 3c sticky-case problem on comp.sys.psion.misc, together with established soft-touch coating restoration practice.
  4. ↑ 4.0 4.1 Psion Series 3/3a community FAQ material and the comp.sys.psion newsgroup archives. Source for the battery lead problem and its fix.


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