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Psion Series 3c Hinge Repair

From RetroTechCollection
The 3c uses the same four-hinge clamshell as the rest of the family. The differences are the case coating and the SSD door contacts you will meet on the way in.

Hinge repair for the Psion Series 3c (1996).

The 3c uses the same case and the same four hinges as the Series 3, 3a and 3mx. The full procedure โ€” hinge locations, both failure modes, the epoxy repair, the complete teardown, lid separation and reassembly โ€” is on the Psion Series 3a Hinge Repair page and applies here unchanged.

This page records the 3c differences.

The four hinges

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Two visible hinges beyond either end of the button bar, with a metal rod down the centre; two hidden plastic nipples between the battery compartment and the button bar. The visible hinge shears at its 8 mm neck, usually from over-opening the lid; the hidden nipple simply breaks off, leaving the back edge crooked and the button bar flexing out. Both repair with epoxy, optionally reinforced with a thin steel strip.[1]

โš ๏ธ Handle the case coating first

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The 3c's matte finish is a rubberised soft-touch coating that degrades into a glue-like layer.[2]

If the machine you are working on has reached that stage, strip the coating before you start the hinge repair, not after. Tacky residue on your fingers will end up on the LCD, in the hinge pin bores and on every ribbon contact you touch โ€” and epoxy will not bond reliably to a degraded soft-touch layer anyway. The method is in Psion Series 3c General Maintenance.

SSD doors on the way in

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Open both SSD doors before lifting the mainboard.

On the 3c the doors are sensed by PCB tracks and a small metal connector on the door hinge rather than by microswitches, so you are not at risk of the 3mx's snapped-switch fault โ€” but the contact is still delicate and the habit is worth keeping.[3]

While the machine is open, clean those tracks and the metal contact โ€” it costs nothing and cures a lot of intermittent SSD faults.

Donor lids

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A 3a or 3c lid will physically fit, and both use the 480 ร— 160 panel.[4]

Two cautions:

  • A Series 3 lid will not work โ€” that machine has a 240 ร— 80 panel and a different ribbon.[4]
  • Backlit and non-backlit 3c lids are not the same. Only later models, mainly the US 2 MB machines, were backlit.[5] Match the donor to what you want to end up with, and expect the cosmetic finish to differ between a 3a lid and a 3c one.

Everything else

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Follow Psion Series 3a Hinge Repair for the teardown, the button bar and its springs, the LCD ribbon, the hinge pin extraction, the pre-reassembly power-up test and the reassembly sequence.

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References

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  1. โ†‘ David MacKay, "Psion 3a Hinge breakages". Source for the hinge locations, both failure modes, the over-opening cause and the epoxy repair.
  2. โ†‘ Community discussion of the Psion 3c sticky-case problem on comp.sys.psion.misc, together with established soft-touch coating restoration practice.
  3. โ†‘ Richard Zealley, "Psion Series 3mx SSD door microswitch repair", Retro Coding, 25 May 2020. Source for the 3c door-sensing arrangement.
  4. โ†‘ 4.0 4.1 "Psion specifications", netogram.com. Source for the shared 480 ร— 160 screen resolution across the 3a, 3c and 3mx, and the Series 3's different 240 ร— 80 panel.
  5. โ†‘ "Psion Series 3", Wikipedia. Source for the backlight availability on later 3c models.