Psion Siena Troubleshooting Guide

A Siena. Half of what people report as faults on this machine are deliberate omissions — no SSD bays, no power socket, no sound recording, no backlight.

Fault-finding for the Psion Siena (1996).

The Siena is a SIBO machine, so the four power states and the supply rail chart in the Psion Series 3a Troubleshooting Guide apply here too. What does not apply is anything to do with the Series 3 case: the Siena has no button bar, no four-hinge clamshell and no internal SSD bays, so those faults simply do not exist on it.

⚠️ Before you start

• Back up through the serial port first. It is the only route in or out of the machine, and diagnosis means removing batteries.
• There is no external power socket, so you cannot keep the machine alive from an adapter while you work. The CR1620 backup cell is all you have.
• Anti-static precautions throughout.

Step 1: rule out the things that are not faults

A large share of reported Siena "faults" are design decisions.

Not faults

Reported as	Assessment
No SSD slots anywhere on the machine	Correct. The Siena has no internal bays. Storage expansion is an external SSD or PC-Card drive on the serial port.
Nowhere to plug in a mains adapter	Correct. There is no external power input at all.
Will not record sound	Correct. The Siena has a piezoelectric beeper only — no microphone, no CODEC. Recording is a Series 3a/3c feature.
Screen is dim in poor light	Correct. No backlight was ever fitted.
Series 3 software misbehaves or will not fit	Expected. The Siena is binary compatible with the Series 3, but many programs needed modification for the smaller screen (240 × 160) and smaller memory.
A Series 3 or 3a serial cable will not fit	Expected. The Siena connector matches the 3c.

Step 2: power

With no mains input, every intermittent fault on a Siena is a power fault until proved otherwise.

Symptom	Cause	Action
Will not switch on	Flat or poorly-contacting AAA cells; machine held in the SIBO backup state because the main supply is not reaching the board	Fit known-good alkaline AAAs and check them under load. Clean the contacts in the compartment under the detachable top casing.
Loses data on every battery change	Flat or badly-contacting CR1620. On a Siena there is no adapter to fall back on, so a weak backup cell loses everything	Replace the CR1620 and check the contact pressure.
Runs down cells quickly	AAA cells hold roughly a third of an AA's energy — the Siena is simply working from less	Compare against a fresh set before assuming a fault. If the drain is genuinely abnormal, check for a shorted or leaky cell contact.
Corrosion in the battery compartment	Leaked AAA cell	Neutralise and clean. In a case this small the electrolyte has very little distance to travel. See Battery Explosion, Capacitor or Corrosion Damage.

Step 3: the serial port

If the serial port does not work, the machine is effectively sealed.

Symptom	Cause	Action
No PC connection	Wrong cable; dirty connector; baud rate mismatch	Confirm you have a 3c/Siena cable. Clean the connector. The Siena serial runs at 19,200 bit/s.
External SSD or PC-Card drive not recognised	Cable, connector, or the drive itself	The Siena drives external storage over the same serial link, so a serial fault and a storage fault look identical. Test the link with a PC first.
Infrared transfers fail	Dirty or scratched IR window; misalignment	The IR port sits next to the serial port. Clean it; IR needs line of sight at both ends.

Step 4: display and keyboard

Symptom	Cause	Action
Display blank, machine otherwise alive	Contrast out of range, or the Vcc3 / Vee1 rails	Adjust contrast in software first. On SIBO machines contrast is a software-controlled DAC driving the negative Vee1 rail — there is no wheel to turn, so if the software control does nothing the rail has failed.
Display scrambled or badly timed	LCD controller or its timing, with Vcc3 healthy	A board-level fault.
Whole keyboard dead	Keyboard scanning	The matrix is scanned by driving each column in turn and reading the rows, so a whole dead keyboard points at the scanning path rather than at the keys.
A row or column of keys dead	One matrix line	Trace that line.
Keys need a hard press	Dirty membrane or pads	Wash the membrane, clean the pads. See Psion Siena General Maintenance.
Numeric keypad dead, main keyboard fine	Its own matrix lines	The Siena's numeric keypad beside the screen is part of the same matrix; treat it as another block of rows and columns.

Step 5: the shared SIBO material

For the four power states (standby, backup, idle, operating), the supply rail chart and the watchdog behaviour, see Psion Series 3a Troubleshooting Guide. The Siena runs the same V30H at 7.68 MHz and the same architecture.

One rail note specific to this machine: the +16 V Vh Flash programming rail exists to serve SSD slots, and the Siena has none internally. If you are using an external drive and Flash packs read but will not format, the fault is in the external drive, not in the Siena.

What is realistically repairable

Part	Repairable?	Notes
Battery contacts and compartment	Yes	The commonest real fault.
Serial connector	Yes	Worth the effort — it is the only route in or out.
Keyboard membrane	Yes	Washable.
LCD panel	With a donor	Siena-specific 240 × 160 panel; nothing else in the range fits.
Mainboard	Board-level swap only	Dense surface-mount SIBO construction.
ASIC	No	Psion custom silicon.

Related pages

• Psion Siena · Psion Siena General Maintenance
• Psion Series 3a Troubleshooting Guide — the shared SIBO diagnostics
• Battery Explosion, Capacitor or Corrosion Damage · Recommended Tools