Psion Series 3a Hinge Repair

Psion Series 3a, open. The visible hinges are at each end of the application button bar.

The Psion Series 3a clamshell has four hinges, and broken hinges are one of the documented weak points of the Series 3 family, along with the button bar and the screen cable. When the machines were current a broken hinge meant returning the machine to Psion or a dealer. Psion Inc's technical manager put left-hinge failures at about 1.5 % of all returns. All four hinges can be repaired.

Identifying the broken hinge

Series 3a 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 on the button bar that locate in holes in the case	The peg breaks off

A broken hidden hinge makes the back of the machine sit crooked as it opens and lets the button bar flex outwards. David MacKay attributed the visible-hinge failure to over-opening the lid, which bends the metal pin and twists the neck.

Before you start

• Back up the internal disk. The repairs below remove the batteries, and the machine loses its memory if the main cells and the backup cell are both out.
• Work on an earthed mat with a wrist strap; the boards are CMOS.
• Do not bend the LCD module. Its circuit board can crack, and liquid crystal from a broken panel should be washed off skin at once with soap and water.
• Work over a tray. The hinge pins and springs are small.

Repairing a visible hinge

David MacKay repaired a sheared visible hinge twice with epoxy (Araldite): 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.
2. Clean both faces of the break.
3. Bond the piece back with epoxy, with or without a thin steel reinforcing strip across the joint.
4. Leave the epoxy to cure fully before using the hinge.
5. Do not open the lid past its stop afterwards.

A broken visible hinge can also be dealt with by fitting a lid from a donor machine; see Separating the lid from the base.

Repairing a hidden hinge

The hidden hinge is a peg moulded on the button bar arm. The repair described in the comp.sys.psion FAQ replaces the peg with a piece of wire held in place by the hinge spring, with no glue.

1. Back up, then remove the battery cover, the batteries and the four screws in the battery compartment.
2. Swing out the battery housing, slip the rubber collar on the blue battery lead out from under its holder, and unplug the lead by the plug, not the wires.
3. Slip the loops of the two hinge springs off their pegs and lift the long arms of the springs out of the button bar to release it. The bar is still attached by its cable.
4. Turn the button bar until the stump of the broken peg is visible, and drill a 1–2 mm hole through the root of the peg. MacKay used a sharp precision screwdriver as the drill; the plastic is soft.
5. Cut about 2 cm of 1–2 mm 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, then refit the springs: long arms first, then the loops onto their pegs. The spring holds the new peg in place.
7. Reconnect the battery lead, refit the housing and restore the batteries.

MacKay made his peg from a paper clip bent double for thickness; another owner used a small round-headed nail sawn to length, with the head filed to a D shape and superglued in place.

Separating the lid from the base

Separating the halves is the route to fitting a donor lid, and to the LCD cable.

Removing the main board

1. Remove the main and backup batteries.
2. Remove the four screws in the battery compartment, lift the battery cable over its catch and pull the battery connector off the main board by its edges.
3. Open SSD slot B and remove the screw. Open SSD slot A and remove the screw, which is usually under the warranty label.
4. Working one side at a time, lift the keyboard cover from the bottom case. A small screwdriver in the vacant SSD screw holes pushes the cover up far enough to get fingers under it.
5. Pull the cover forward and up so that its small plastic tab comes out from under the hinge, then repeat on the other side.
6. Release the top tabs with a small flat screwdriver working under the button bar, which bows outwards under spring pressure at this point.
7. Release the two tabs at the bottom of the cover. Removing the rubber membrane and keys first makes this easier. On some keyboards the keys are not attached to the membrane, so lift it carefully.
8. Lift the front of the main board with a small screwdriver in the slot at the front, using as little force as possible because the plastic rim marks easily. Push the 3-Link port shutter in and lift the board out.

Separating the halves

1. Remove the blue button-bar ribbon cable: push up the edges of the connector and pull the cable out gently.
2. Push one end of the button bar so that its small plastic hinge next to the battery housing pops out, then repeat at the other end.
3. Push the metal springs off their mountings on the button bar and ease the bar back through the gap between the halves. Remove the springs from the case; they need a little wobbling to come free.
4. Release both sides of the LCD cable connector and pull the cable out. Psion's connectors are ZIF sockets with a locking bar; a released cable comes out with no resistance, and forcing a cable out of a locked socket damages it.
5. Make a gap between the head of each hinge pin and the hinge with a thin blade or a fingernail, without scratching the pin head, then pull the pin out with long-nose pliers with tape over the jaws.
6. The lid and base are now separate.

On a machine with a TAB LCD module (built from September 1995), the LCD can be removed from the lid without taking out the hinge pins: remove the two micro-screws at the ends of the LCD outer moulding and release the four clips at the middle of the bottom edge of the screen.

Reassembly

1. Rejoin the halves and push the hinge pins fully home. Their heads must be flush with the battery moulding or they catch on the hinge link, and they should be a tight fit; a loose pin works out and can jam the hinge mechanism.
2. Refit the LCD cable squarely into its ZIF socket and lock it.
3. Before going further, connect the main board and the membrane, plug in the mains adaptor and press Esc. The start-up screen should appear; if it does not, the LCD cable is not seated.
4. Feed the button bar through the gap at the front of the halves and locate the plastic pegs on its sides in the holes beside the battery housing.
5. Refit the hinge springs, each in its own left- or right-hand socket. The end of the spring goes into the slot at the rear of the button bar while the round part fits over the round part of the bar.
6. Reverse the disassembly. Press the bowed button bar flat as the case closes so that it does not catch.

Parts

Hinge parts in Psion's service manual

Part	Psion part number
Hinge spring, left-hand	8403-0014-01
Hinge spring, right-hand	8403-0015-01
Button bar assembly	2501-0068-01
Micro screw (LCD outer moulding)	8304-0003

TAB LCD machines use hinge springs dyed blue; earlier machines use black springs.

Other Series 3 models

The Psion Series 3 is similar but not identical: the Series 3a can be dismantled without separating the LCD and keyboard mouldings, and the Series 3 has wires where the 3a has board-to-board connectors. See Psion Series 3 Hinge Repair.

The Psion Series 3c and Psion Series 3mx detect the SSD doors differently. The 3c uses tracks and a small metal contact on the door hinge; the 3mx uses a pair of angled microswitches whose plastic tips snap off if the main board is prised up with the SSD doors closed, after which the machine does not see its SSDs. Open both SSD doors before lifting the main board. See Psion Series 3c Hinge Repair and Psion Series 3mx Hinge Repair.

The Psion Siena has a different, smaller case.

Related pages

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