Psion Series 3 Hinge Repair

A Psion Series 3

Hinge repair for the Psion Series 3 (1991). The Series 3 clamshell has four hinges, and breakage of any of them is one of the range's documented faults, with the button bar and the screen cable. The repairs below were described by owners of the Series 3a, which has the same hinge layout. The Series 3 is not identical inside: it has wires where the 3a has board-to-board connectors, and Psion published no service manual for it.

The four hinges

Series 3 family hinges

Hinge	Location	Construction	How it fails
Two visible hinges	Just beyond each end of the button bar	Moulded hinge with a metal pin through the centre	The 8 mm neck joining the hinge to the lid shears off about 2 mm above the hinge
Two hidden hinges	Between the battery compartment and the button bar	Plastic pegs that locate in holes in the case	The peg breaks off; the back of the machine then looks crooked as it opens and the button bar flexes outwards

David MacKay attributed the visible-hinge failure to over-opening the lid, which bends the metal pin and twists the neck. Open the lid only to its natural stop.

Before starting

• Back up everything. The hidden-hinge repair disconnects the main battery lead, leaving the machine on its backup cell; fit a fresh backup cell or keep a mains adaptor connected, or accept that the internal memory may be lost.
• Work on an earthed mat with a wrist strap; the boards are CMOS.
• Work over a tray. The hinge springs and pins are small.

Tools and materials

• Small cross-head screwdriver, craft knife and tweezers
• A small drill or a 1–2 mm square nail or drill bit
• 1–2 mm spring wire, wire cutters and pliers
• Epoxy adhesive (MacKay used Araldite), and optionally a thin strip of steel

Repairing a visible hinge

MacKay repaired a sheared visible hinge twice with epoxy: the first time with a thin piece of steel glued across the break as reinforcement, the second time with a blob of epoxy alone. Both repairs held.

1. Recover the broken piece and clean both faces of the break.
2. Bond the piece back with epoxy, with or without a thin steel strip across the joint.
3. Leave the epoxy to cure fully before using the hinge.

A donor lid is the other route. The Series 3 screen is 240 × 80 and the 3a's is 480 × 160, so a donor lid must come from another Series 3.

Repairing a hidden hinge

The repair published in the comp.sys.psion FAQ, by Charlotte Holmquist with comments from Steve Hawtin, replaces the broken peg with a bent piece of spring wire that the hinge spring holds in place, with no glue.

1. Remove the battery cover, the batteries and the four small screws, and swing the battery holder out.
2. The battery lead runs under a holder, protected by a rubber collar. Slip the collar out from under the holder and unplug the lead by the plug, not the wires.
3. Slip the loops of the two hinge springs off their plastic pegs, then lift the long arms of the springs out of the button bar to release it. The button bar is still attached by its cable.
4. Turn the button bar until the root of the broken peg is visible, and drill a 1–2 mm hole through it.
5. Cut about 2 cm of spring wire and bend it to a right angle in the middle. Trim one end so that 1–1.5 mm reaches into the case through the new hole, and the other so that it lies in the slot where the spring arm rests. The finished piece is about 5 mm long.
6. Fit the new peg through the hole into the case, with its other arm in the spring slot.
7. Refit the springs, long arms first, then the loops onto their pegs. The spring holds the new peg in place.
8. Reconnect the battery lead, refit the holder and the screws, and restore the batteries.

Steve Hawtin's variant detaches the button bar completely, which on the 3a means releasing the keyboard board and unplugging the button bar ribbon. Hawtin notes that the Series 3 has wires at that point where the 3a has connectors. Hawtin made his peg from a small screw with its head cut off.

After the repair

• Open and close the lid several times and check that the button bar sits flush and every button responds.
• Check the battery warnings: the battery lead is disturbed by this repair and is itself a common failure on older Series 3 machines.

Related pages

• Psion Series 3
• Psion Series 3 General Maintenance
• Psion Series 3 Troubleshooting Guide
• Psion Series 3a Hinge Repair
• Recommended Tools