Psion Revo Troubleshooting Guide
Fault-finding for the Psion Revo (and, with the differences noted, the Psion Revo Plus and Diamond Mako).
Start with the battery. The Revo was notorious for battery and charging problems, and after twenty-five years the cells in an untouched machine are certainly worn out.[1]
⚠️ Before you start
[edit | edit source]- Back up through the dock or IrDA first. There is no card slot, and opening the machine to reach the cells factory resets it.[2]
- There is not a millimetre to spare inside a Revo. It is an awkward machine to work on and disassembly is risky.[2]
Step 1: battery and charging
[edit | edit source]| Symptom | Cause | Action |
|---|---|---|
| Runtime collapsed; will not hold a charge | Worn NiMH cells. Original stock is 700 mAh and dates from 1999–2003 | Replace them. See Psion Revo Battery Replacement. |
| Dies intermittently; resets for no reason; will not charge | The battery connector working loose. Original Revos suffer from batteries coming loose and unplugging — fixed on the Plus | Open the machine and secure the connector with hot-melt glue or silicone. Not superglue.[1][2] |
| Battery meter obviously wrong | The hardware has not been recalibrated | Hard reset, then charge uninterrupted from 0 % to 100 % — about six hours at stock capacity, preferably switched off. Ignore the meter during that charge.[1] |
| Red charging light goes out well before full | Normal. It turns off at around 84 % | Not a fault.[1] |
| Cells get hot; charge never terminates | Overcharging. Charge termination senses a thermal change around 80 %; if the machine is put on charge above that level the change is missed | Do not charge either Revo model when the battery is already above about 80 %.[1] |
| Charges erratically after a cell replacement | Damaged thermistor. A strip of circuit ribbon wrapped in with the cells acts as the temperature sensor | It must be intact and held against the cell body. Rewrap the pack correctly.[2][1] |
| Replaced cells behave oddly | Wrong chemistry | NiMH only. The charging circuit is designed around it.[1] |
| Fitted higher-capacity cells and the charge seems short | Expected | Work out and extend the charge time proportionally.[1] |
Step 2: the case microswitch
[edit | edit source]A microswitch on the rear switches the Revo on and off as the case is opened and closed. It is easily broken by too much force when refitting the battery bay — which means it is very often broken on a machine that has already been opened once.[2]
| Symptom | Assessment |
|---|---|
| Does not wake on opening, or does not sleep on closing | Broken or displaced case microswitch. Frequently the legacy of a previous battery replacement.[2] |
| Machine will not open or close properly after a repair | The battery pack is not seated correctly. Check this before suspecting the hinges.[2] |
Step 3: things that are not faults
[edit | edit source]| Reported as | Assessment |
|---|---|
| No backlight | Correct. The Revo was built without one. |
| No CompactFlash or card slot | Correct. The Revo has none. Data moves by the docking station or IrDA. |
| Screen smaller than a 5mx | Correct. 480 × 160 against the 5mx's 640 × 240. |
| Cannot change the batteries | Correct. They are soldered in and sealed under the nameplate. |
The backlight story
[edit | edit source]There is a persistent claim that Psion left the backlight wiring in place and omitted only the lamps. Pads marked EL+ and EL− do exist under black tape on the screen PCB — but a voltmeter across them gave no reading, AC or DC, with the unit on and with the Fn + Space sequence that works on a Series 5.[2]
Fitting a backlight to a Revo has not been shown to work.
Step 4: screen and connectivity
[edit | edit source]| Symptom | Cause | Action |
|---|---|---|
| Screen ribbon will not come out | The connector restraint is not properly lifted | With the restraint up the ribbon needs no force. Do not force it — lift the restraint properly.[2] |
| Screen cracked during disassembly | Too much pressure prising it from the surround | Start unclipping at the bottom and work up the sides, gently. The rear of the screen is metal-encased and tolerates gentle levering; the glass does not.[2] |
| No serial connection | Dock contacts, cable, or baud rate | The Revo does RS-232 on a 9-pin D-sub at up to 115,200 bit/s, through the docking station.[3] |
| IrDA transfers fail | Dirty or scratched window; misalignment | Clean it. IrDA needs line of sight at both ends. |
| Touchscreen inaccurate | Calibration lost after a total power loss | Recalibrate through the operating system, as on any EPOC machine. |
Step 5: the shared EPOC material
[edit | edit source]The Revo runs the same 36 MHz ARM710T and the same Symbian (EPOC32) Release 5 as the 5mx, and is software compatible with it.[1]
For the reset levels, the Battery Information screen at Shift-Ctrl-P, the touchscreen calibration behaviour and general EPOC diagnosis, see Psion Series 5mx Troubleshooting Guide.
What does not carry over is anything to do with the 5mx's case: the Revo has no sliding keyboard, no spring hinge wires and no CompactFlash door, so those faults do not exist here.
What is realistically repairable
[edit | edit source]| Part | Repairable? | Notes |
|---|---|---|
| Battery pack | Yes | The standard job. See Psion Revo Battery Replacement. |
| Battery connector | Yes | Reseat and glue. |
| Case microswitch | Difficult | Small, fragile, and easily lost during a repair. |
| Screen | With a donor | Very easily shattered during removal. |
| Mainboard | Board-level swap only | Dense surface-mount construction. |
Related pages
[edit | edit source]- Psion Revo · Psion Revo General Maintenance · Psion Revo Battery Replacement
- Psion Revo Plus Troubleshooting Guide
- Psion Series 5mx Troubleshooting Guide — the shared EPOC diagnostics
- Battery Refurbishment · Recommended Tools
References
[edit | edit source]- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 "Psion Revo", Wikipedia. Source for the battery notoriety, the cell specification, the loose-battery problem and its fix in the Plus, the NiMH-only requirement, the over-80 % charging caution, the recalibration charge, the 84 % charging-light behaviour, and the machine's omissions relative to the 5mx.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 David Savery, "Psion Revo/Diamond Mako Disassembly & Battery Replacement", R3UK, 2004. Source for the factory reset warning, the disassembly procedure, the thermistor, the case microswitch, the screen ribbon restraint and the EL pad measurements.
- ↑ "Psion 3mx, Psion 5, Psion 5mx, Psion Revo and Psion Revo Plus specifications", netogram.com. Source for the Revo interfaces, docking station, run time and power adapter rating.