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

2026-09-08T22:52:36Z

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

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[[File:Psion Series 3c.jpg|thumb|420px|A Series 3c. Mechanically it is a 3a, so the common maintenance is shared — but the rubberised case coating and the SSD door contacts are its own.]]

Preventive maintenance for the '''[[Psion Series 3c]]''' (1996).

The 3c shares its case, hinges, button bar, keyboard, battery arrangement and internal architecture with the [[Psion Series 3a|3a]]. '''The full common procedure is in [[Psion Series 3a General Maintenance]]''' — this page covers what is specific to the 3c.

== The sticky case ==

'''Deal with this before it gets onto your tools, your bench and everything else you touch.'''

The 3c's matte dark grey case is a '''rubberised soft-touch coating''', and with age it degrades into a tacky, glue-like layer.<ref name="sticky">Community discussion of the Psion 3c sticky-case problem on comp.sys.psion.misc, together with established soft-touch coating restoration practice. Source for the degradation of the coating and the isopropyl alcohol stripping method and its cautions.</ref>

The reliable fix is '''controlled removal of the degraded layer''', not an attempt to rescue it:

# '''Remove the batteries''' — both AA cells and the CR1620 — and take the machine apart far enough that no liquid can reach the electronics. Mask the ports.
# Work '''in good ventilation''', with '''nitrile gloves'''.
# Use '''high-purity isopropyl alcohol''', 90–99 %, on a cloth. IPA dissolves degraded soft-touch polyurethane and then evaporates cleanly, which is why it is preferred over household solvents.<ref name="sticky" />
# Work in small areas, wiping rather than scrubbing, changing to a clean part of the cloth often.
# '''Stop immediately''' if the plastic underneath whitens, crazes or clouds, or if printed legends begin to smear.<ref name="sticky" />
# '''Let the case dry for several hours — up to a day — before reassembling or powering up.'''<ref name="sticky" />

A gentle abrasive paste such as bicarbonate of soda is a documented alternative for stubborn areas, and various users report success with other mild solvents, but IPA is the method with the most predictable result.<ref name="sticky" />

The result is a matte plastic case rather than a soft-touch one. That is the trade: the original finish cannot be restored, only removed.

== SSD door contacts ==

The 3c senses its SSD slot doors with '''PCB tracks and a small metal connector on the door hinge''', not with microswitches.<ref name="rc3mx">Richard Zealley, [https://www.retrocoding.uk/psion-3mx-ssd-microswitch-repair/ "Psion Series 3mx SSD door microswitch repair"], Retro Coding, 25 May 2020. Source for the 3c door-sensing arrangement and its difference from the 3mx.</ref>

* '''Clean the tracks and the metal contact''' with isopropyl alcohol on a swab whenever the machine is open.
* They are a contact, so they tarnish. A 3c that intermittently fails to see a pack is worth cleaning here before anything else.
* '''Still open both SSD doors before lifting the mainboard.''' The 3c does not have the 3mx's fragile switch tips, but it is a good habit across the family.

== Backlight ==

Later 3c models — mainly the US 2 MB machines — have a '''backlit screen'''.<ref name="wp3">[https://en.wikipedia.org/wiki/Psion_Series_3 "Psion Series 3"], Wikipedia. Source for the backlight availability, the case redesign and the infrared port.</ref> A 3c without one is not faulty.

Where a backlight is fitted, it draws significant current: expect noticeably shorter battery life with it on, and check it is not being left on before investigating a battery-life complaint.

== Infrared and serial ==

* '''Keep the infrared window clean and unscratched.'''
* '''The 3c serial port differs from the 3a's''' and matches the [[Psion Siena|Siena]]'s. A 3a cable will not fit, and '''Travel Modem connections differ between the 3/3a and the 3c/3mx'''.<ref name="wp3" />
* Keep the serial connector clean and its cover closed.

== Batteries ==

2 × AA cells, a '''CR1620''' backup cell and a 9 V 150 mA external supply, as the 3a.<ref name="wp3" /><ref name="spec">[https://www.psion.netogram.com/psionspecifications.html "Psion specifications"], netogram.com. Source for the comparative model specifications.</ref>

'''The battery lead is still the fault that eats cells''' — see [[Psion Series 3a General Maintenance]].

== Capacitors ==

'''Not a recap candidate.''' See the reasoning in [[Psion Series 3a General Maintenance]].

== Preventive maintenance checklist ==

# Back up to an SSD or a PC.
# Assess the case coating; strip it if it has gone tacky.
# Clean the SSD door tracks and contacts.
# Clean the infrared window and the serial connector.
# Inspect the battery lead and re-seat the two-pin connector.
# Check all four hinges.
# Confirm the button bar sits flush and responds.
# Replace the CR1620 if you do not know its age.
# If backlit, confirm the backlight works and is not being left on.

== Related pages ==

* [[Psion Series 3c]] · [[Psion Series 3c Troubleshooting Guide]] · [[Psion Series 3c Hinge Repair]]
* [[Psion Series 3a General Maintenance]] — the shared procedure
* [[Battery Explosion, Capacitor or Corrosion Damage]] · [[Recommended Tools]]

== References ==

<references />

{{Navbox-Psion}}

[[Category:Psion]]
[[Category:Maintenance Guides]]

Psion Series 3c General Maintenance - Revision history

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