Psion Series 3c General Maintenance

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 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.

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

1. 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.
2. Work in good ventilation, with nitrile gloves.
3. 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.
4. Work in small areas, wiping rather than scrubbing, changing to a clean part of the cloth often.
5. Stop immediately if the plastic underneath whitens, crazes or clouds, or if printed legends begin to smear.
6. Let the case dry for several hours — up to a day — before reassembling or powering up.

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.

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.

• 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. 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 Siena's. A 3a cable will not fit, and Travel Modem connections differ between the 3/3a and the 3c/3mx.
• 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.

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

1. Back up to an SSD or a PC.
2. Assess the case coating; strip it if it has gone tacky.
3. Clean the SSD door tracks and contacts.
4. Clean the infrared window and the serial connector.
5. Inspect the battery lead and re-seat the two-pin connector.
6. Check all four hinges.
7. Confirm the button bar sits flush and responds.
8. Replace the CR1620 if you do not know its age.
9. 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