Psion 5mx case repair
I picked up a water damaged Psion 5x to have some spare parts available to repair the first Psion 5x I bought.
 |
| Psion in pieces with screens being repaired |
The first Psion had a broken screen and was sold as "fixable, complete with spare screen" the "spare screen" however had clearly been poorly removed from somewhere and had missing PCB pads and traces. The currently installed screen had a cracked cable.
 |
| A cracked screen cable |
Sigh.
My "donor" machine took ages to arrive, so instead I thought I'd see how I got on with some repairs instead. First I tried repairing the cracked flex cable, with no success, so ordered some new ones from JLCPCB... Second course of action, I decided to repair the spare screen, first cleaning up the contacts then carefully adding a new PCB pad, and connecting it up. and yes, I wished I'd taken some pictures of the PCB repair before I soldered the ribbon cable back on, but after connecting the cable and firing it up... it worked. yay.
 |
| A working psion 5mx screen |
Then, perfect timing, my donor machine arrived. 🤦
Ok... first asses - the keyboard cable and connector was "gunked" up, there were signs of liquid damage on the keyboard and the battery contacts were corroded. But it didn't look too bad. First a complete strip down, thoroughly clean all contacts and connectors with isopropyl alcohol, remove all corrosion off the battery contacts, dismantle and clean screen, re-solder a few contacts that looked unhappy, thoroughly cleaned the keyboard and dried everything thoroughly.
and powered up.... I was surprised it actually worked!
 |
| A working fully dismantled Psion 5mx |
So. I now have two working Psion 5mx's. However, the next problem with the "sacrificial donor machine" was that the hinges for the screen were broken, a common 5mx problem. The inner chassis seems incredibly fragile, clearly it's degraded over time. I try some glue repairs for the cracks, but the two hinge clips are completely missing. I wonder, can I make a replacement?
 |
| Psion chassis with broken and missing clips |
As luck would have it... there appears to be an almost complete model on printables by Jon!
 |
| Screen shot of design on printables |
however it's missing one of the hinge clips and has a comment that it hasn't been tested and might be incomplete.. but the author was planning on finishing it. several years ago. Time to start printing tests and tweaking. After a few iterations I print the half with the hinges and start measuring/testing, it looks good.
 |
| 3D printed hinge tests |
Time passes. prints are made. I decide for now I'll try printing in two halves, after a few tricky attempts I have a working chassis to build around.
The first test prints at 0.4mm just weren't strong enough with the layer lines being horizontal at critical points, but it was a good way to quickly test fit and size.
The hinges still needed a little tweaking, but also snapped as soon as stress was applied. Time to try some PLA tough...
 |
| Chassis parts glued together |
 |
| Chassis with keyboard attached |
 |
| Screen fitted to chassis |
 |
| PCB mounted into chassis |
 |
| Complete assembed and opened Psion |
Finishing rebuilding and it works! I can open and close now. YES!
I make a few more iterations and fix a few minor issues, attempts at a "one piece" print were a complete disaster, as was my PETG print (spaghetti attack). The 0.4mm prints are too course, so I switch to a 0.2mm nozzle, kicking off several 15+ hour prints.
I needed to fix the battery compartment space and the screw holes were too small, moved the hinge catches back and strengthened slightly.
The updated 3D models are now uploaded to Makerworld.
Once I'm happy with the model I intend to get a high quality professional print from JLC3DP done, but if anyone else wants one I can get several ordered.
