Psion Series 5 Hinge Cable Repair

Screen cable and hinge repair for the Psion Series 5 (1997).

A Series 5. The screen ribbon runs through the hinge, cracks around a hole left by the manufacturing process, and takes the display with it. It is the defining failure of this platform.

The Series 5 shares its mechanical platform with the 5mx, so the full teardown, the hinge-hook failure and the printed-chassis replacement are covered in Psion Series 5mx Hinge Repair and apply here. This page covers the screen ribbon cable, which is the Series 5's own most common failure — and the one part where Series 5 and 5mx are definitively not interchangeable.

The screen ribbon

Symptom: horizontal lines across the display, appearing suddenly, often on opening the machine. Sometimes the display works if the lid is opened only part way.

Cause: the flexible plastic ribbon connecting the mainboard to the screen cracks around a hole in the plastic that was used during manufacture to hold the cable in position. That hole is a stress raiser; years of flexing the lid fracture the plastic around it, and as soon as the fracture cuts a signal conductor the display fails.

The fracture is minute — expect to need magnification. It sits under the sticky black plastic covering the solder points at the screen end.

⚠️ Series 5 and 5mx cables are different

Do not order a 5mx cable for a Series 5.

The two machines look almost identical from the outside, and their mainboards, screens and other internal components are different and not interchangeable.

Identify the machine first: a Series 5 has a CL-PS7110 at 18.432 MHz with 4 or 8 MB of RAM; a 5mx has Psion's Windermere SoC at 36 MHz with 8 or 16 MB.

Aftermarket cables redesigned to remove the original design flaw have been produced by the community, for both machines.

Back up before you start

The failure arrives without warning, so if the machine still shows anything at all, get the data off first.

• Opening the lid only about a centimetre often restores the display long enough to work with.
• If it does not, use the blind backup procedure in Psion Series 5mx Troubleshooting Guide — System icon, Ctrl-L, C for cable, down arrow, 5 for 57600, Enter — then back up from PsiWin.

Temporary repairs do not last

Bridging the broken track works, briefly.

One documented attempt cut a conductor from a scrap ribbon, soldered it from the failed track's pad on the rear of the LCD around to the opposite end of the original broken track, and secured everything with hot glue. It worked — and lasted about four days in daily use.

Two practical notes from that attempt, if you try it anyway:

• The solder points at each end of the original ribbon are on opposite sides, so the patch conductor has to be folded around.
• The pads are tiny and bridge easily. Two attempts failed on minute solder splashes shorting adjacent points. Clear them by running a blade between the pads and check with a continuity tester before reassembling.

The only real fix is a new cable.

Disassembly

Psion's own procedure is in the Psion Series 5 Service Manual, hosted on this wiki. The practical sequence — and the model-specific notes for a 5mx — are in Psion Series 5mx Hinge Repair.

Points that matter particularly on the Series 5:

• Remove the stylus, both battery sources and any Memory Disk first.
• Three case screws, one of them under the "Warranty Void if Removed" label.
• Open the Memory Disk and lithium doors before lifting the base moulding — this frees locating clips between the PCB and the moulding.
• Remove the hinge cover with the battery housing door closed.
• Lift the PCB to expose the LCD (orange) and keyboard (blue) flexi connectors in their LIF sockets. Resting the assembly on the edge of a raised surface such as a book lets the PCB drop and gives the cables more slack.
• The hinge pins need the factory removal tool, which no longer exists. The workable substitute is to insert a thin precision screwdriver into the tube and wiggle while pulling, with a drop of penetrating oil to help.
• The LCD/keyboard hinge pin is documented as needing the inner moulding cut away, but it has a head, so a sharp blade can get purchase and draw it out intact.
• The LCD and digitiser are best treated as one assembly. Psion recommend replacing them together, because the conductive strip and the clamp are placed at the factory with accurate equipment and are difficult to fit precisely by hand.

Reassembly

• Insert the FFCs squarely — at an angle they cause short or open circuits — and retain the existing bends so everything lines up on the PCB.
• Check the pen eject mechanism has not dislodged before replacing the base; its spring drops out easily.
• Have the machine open when refitting the PCB and base, with the Memory Disk and lithium doors open, so the switches are not fouled.
• Do not over-tighten the case screws — they strip the chassis moulding.
• Check the backlight before closing up; it is delicate and easily damaged during servicing.

Hinge hooks

The Series 5 has the same spring hinge wires retained by plastic hooks as the 5mx, and the same failure: the hooks embrittle under constant tension and break, after which the lid no longer opens or closes correctly.

A 3D-printed replacement inner chassis exists — although it is modelled for the 5mx — and the failure, the bodge repairs and the printing guidance are all covered in Psion Series 5mx Hinge Repair.

Related pages

• Psion Series 5 · Psion Series 5 General Maintenance · Psion Series 5 Troubleshooting Guide
• Psion Series 5 Service Manual
• Psion Series 5mx Hinge Repair — the full teardown and the printed chassis
• Recommended Tools