Psion Series 7 Troubleshooting Guide

Psion's layout diagram of the Series 7. The small hole to the right of and in front of the keyboard is the microphone, not a reset hole.

The reset button is inside the lithium backup battery compartment on the underside, beside the coin cell.

Troubleshooting guide for the Psion Series 7. The Series 7 and the Psion netBook share the same motherboard and case, so the mechanical and electrical faults here apply to both. Faults of the netBook's load-from-CompactFlash operating system are in the Psion netBook Troubleshooting Guide; the Windows CE netBook Pro has its own Psion netBook Pro Troubleshooting Guide. Psion published no service manual, parts list or fault-code table for the Series 7 or netBook, so the sources here are Psion's support answers and user guide, the contemporary Series 7 FAQ and documented owner repairs.

Preliminary checks

• Back up first. The internal disk is RAM, and removing batteries can wipe it (see below).
• Remove all batteries, main and backup, before opening the case or changing the ROM or memory module.
• There is no mains voltage inside the machine. The external adapter supplies 15 V DC ± 10 % at 1.5 A. The Li-ion pack is the hazard; see Psion Series 7 Battery Service.
• Take anti-static precautions.

Behaviour that is not a fault

Normal behaviour often mistaken for faults

Behaviour	Explanation
Screen dimmer for about 20 seconds after switching on	Normal for the STN panel.
Backlight cannot be turned off	There is no function to do so. The panel is not reflective, so it looks dimmer in bright light.
Charging LED goes out before the battery is full	The LED goes out at about 70 % charge; a full charge takes up to 3 hours.
Green LED on whenever the adapter is connected	Normal. While charging, the green LED turns yellow and the red LED to its left glows, dimming as the charge proceeds.
Machine stops suddenly without the display fading	Li-ion machines cut out well before the cells are exhausted, and the display does not dim as the battery drains.
CompactFlash card moves about 6 mm in its drawer	Normal; the play is there for Type II devices.
Small hole to the right of and in front of the keyboard	The microphone. The reset hole is under the backup battery hatch.
Old Series 5 Word files very slow to scroll and type in	Copy the contents into a new Series 7 file.

Display faults

Screen cable

If the display fades or goes patchy, or the touchscreen stops registering taps, suspect the screen cable first. The cable itself is usually sound; the clamp connector on the motherboard loses its grip.

Psion's support answer called it "quite a common problem with Psion Series 7s and netBooks". The quick fix is to press firmly on the Series 7 or netBook logo above the keyboard, which often reseats the cable for a while. If that fails, Psion's semi-permanent repair is to open the machine and wedge a piece of cardboard between the cable and the base of the unit. One PsionWiki contributor believed the fault was close to inevitable except on Psion's last batch of netBooks, which had a later fix.

Screen cable repair

Read the whole procedure first. Step 7 can destroy the motherboard.

1. Remove all batteries (main pack and backup cell), the personality (ROM) module and any memory expansion.
2. Cover the keyboard with paper or card, warm the logo sticker with a hairdryer for about 15 seconds and peel it off. Without the cover the key legends lift too. If the sticker does not come away easily, warm it again.
3. Remove the single screw under the sticker.
4. With the screen half open, remove the hinge pins beside the ROM and memory card slots.
5. Lift away the plastic strip carrying the logo, the on/off button and the stylus button. It takes some force; do not crack it.
6. Note exactly how the cable sits in its connector. Connector designs differ; some have a cover held by two screws.
7. Lift the white clamp very gently. If it breaks, the motherboard is a write-off.
8. Shim and reseat. Psion's method is a wedge of cardboard between the cable and the base. The PsionWiki variant is a strip of paper laid parallel with the cable under the clamp and continuing under the two-screw cover.
9. Support the lid while refitting the screws. One owner's repair failed because the screen lay flat and the cable slipped out; a book under the screen fixed it.

Preventing a recurrence

Vibration makes the fault return. One owner's repeat failures stopped when the machine moved from a rucksack pocket that rested against a bicycle to a front pocket. The clamp, not the cable, is the weak part, and replacing the clamp means working on the motherboard.

Display symptoms

Symptom	Probable cause	Action
Display fades, goes patchy, or needs pressure on the logo	Screen cable loose in its motherboard clamp	Press the logo for a temporary cure, then shim the cable.
Touchscreen ignores the stylus or drifts, and recalibration does not help	Screen cable, or the build 754 calibration bug	Press the logo first. Otherwise soft reset. The bug is fixed in build 756; see Build 756 patch before updating.
Blank screen, machine apparently on	Screen cable, or brightness at an extreme	Press the logo, check brightness, then open the machine.
Lit white screen, no beep, after running the 756 patch	ROM erased by a failed flash programming cycle	See Build 756 patch.

Power and battery faults

Removing the battery can wipe the machine

A microswitch in the battery lock is meant to switch the machine off as the catch slides, leaving the backup cell to hold RAM while the pack is out. On some machines it switches the backlight on instead: the screen lights but stays black, the system does not shut down, and when the pack comes out RAM is lost with it.

1. Slide the catch and look at the screen.
2. If it appears to power up but stays black, hold the catch open with one hand and switch the machine off with the other.
3. Then slide the pack out.

One of the rubber feet is on the underside of the battery catch. Sliding the machine across a table, or carrying it loose in a bag, has pulled the catch open and reset the machine.

Power symptoms

Symptom	Probable cause	Action
Internal disk wiped after changing the battery	Battery-catch microswitch lit the backlight instead of powering down	Not recoverable afterwards; use the procedure above next time.
Machine resets in a bag or when slid across a desk	Rubber foot on the battery catch dragging it open	Check the catch and the foot.
Will not switch on at all	Flat pack, pack not seated, or failed pack	Connect the mains adapter and try again. See Psion Series 7 Battery Service.
Corrosion in the backup cell compartment	Leaked coin cell	Neutralise and clean. See Battery Explosion, Capacitor or Corrosion Damage.

Software and ROM faults

Software symptoms

Symptom	Probable cause	Action
Machine slows until applications start but draw nothing	Build 754 fault	Soft reset. The FAQ reports that the problem does not occur on build 756.
Control Panel soft resets when Add/Remove is opened	A stray non-installer file in the install folder	In *:\System\Install\, delete or move any file that does not carry the installer icon.
Patch stops with Vpp not found for all banks	The board's Vpp supply is not coming up	Nothing was erased. Stop; do not retry.

Build 756 patch

Psion did release an operating system update for the Series 7: the Series 7 Patch (build 756), from Psion Enterprise Computing in 2000, consisting of Update.exe, Rom_4mb.img and a readme. The Series 7 FAQ of the time said Psion had made clear there would be no ROM update. The patch can also destroy a machine whose Vpp supply has aged, without warning.

What the patch does

The machine must already be on build 750 or later. Both files are copied to the root of C:, the machine runs from the mains adapter, and Update.exe is started. The screen goes black while the update runs, and a green PASS screen should follow. The readme's warning is to keep the unit on mains power throughout, because "any interruption to the power could lead to an unusable machine".

After PASS, the readme requires the DC jack, the main battery and the backup lithium cell all to be removed, and only then the main battery refitted to reboot. There are two reasons. UPDATE.EXE ends in a deliberate infinite loop after printing PASS or FAIL and never returns to EPOC, so the machine sits there until power is cut. It also never issues a Read Array command to the flash, so the devices stay in status or identifier mode instead of returning ROM contents until power is lost.

A blank or white screen straight after the patch is therefore expected. Remove all three power sources before drawing conclusions.

How it fails

Programming flash needs Vpp, the programming voltage, which these machines generate on the board from the DC input; hence the patch's insistence on mains power.

UPDATE.EXE switches Vpp on and checks it bank by bank by reading each device's status register. The check is static: it confirms the rail is present at that moment, with no erase current flowing. The message on screen shows which of two outcomes occurred, and that decides whether the machine still works.

Reading the patch failure message

Message on screen	What happened	State of the machine
Vpp not found for all banks	The static check failed. The updater returned before issuing any erase or program command.	Undamaged. The ROM was not written and the machine still boots. Do not retry; fix the rail first.
ERASE FAILURE 'Vpp not enabled', or Bank x at y command failed	The static check passed, the erase was commanded, and the rail collapsed under load. The device aborted with its Vpp-low status bit set.	Blocks have already been erased. The operating system is gone and the machine will not boot.

A Vpp supply that measures correctly at rest and sags under erase current passes the check and then fails the operation, and by the time the failure is printed the erase is under way. Erasing proceeds bank by bank, so a failure part way through still leaves erased blocks.

What a failed patch leaves behind

• Backlight on, panel uniformly white, no image.
• No beep on a hard reset, where a working machine beeps once and shows the logo for about ten seconds.
• The reset button blanks the screen, which then returns to white.
• The same behaviour with the ROM card removed.
• On a scope or logic analyser, the ROM address lines sweep continuously from power-on.

The address sweep is the telling symptom. Erased NOR flash reads as 0xFFFFFFFF, which on the ARMv4 architecture of the StrongARM SA-1100 has condition code NV: the word is fetched and never executed. The core walks the whole address space, wraps and repeats. A free-running address bus with no beep and no display is a core fetching from blank or undriven memory.

The same picture with the card out does not prove the ROM is blank. A CPU that never runs and a card that is not making contact look the same. Clean the card edge with isopropyl alcohol and reseat it firmly before going further.

Recovery

There is no software route back. The SA-1100 has no internal boot ROM; it fetches its first instruction from the flash, and there is nothing to fall back on. A Series 7 cannot boot from CompactFlash as a netBook does, because the netBook's card loader is itself code on the netBook's personality module; erase a netBook's module and it is equally dead. The serial loader inside UPDATE.EXE does not help either, as it is part of an EPOC executable and needs a booted operating system. The module has to be replaced or reprogrammed.

• Replace it. Psionex list pre-programmed Series 7 personality modules in builds 751, 754 and 756. This is the only route with a known outcome, and a build 756 module delivers the update as well. The patch ships a 4 MB image, and UPDATE.EXE recognises 2 MB, 4 MB and 12 MB (3 × 4 MB) flash configurations and refuses anything else. The user guide gives the Series 7 12 MB of ROM, while the machine itself reports 16 MB.
• Reprogram it. No method is published. Edward Hasbrouck records that reflashing a module with another machine's image "may be possible", but that David Lowe did not know how to flash-upgrade the personality modules. Rom_4mb.img has a 256-byte EPOCARM ROM header in front of the 4 MB payload, which an external programmer does not want.

Do not run the patch again on a machine that has already failed it. The rail that collapsed will collapse again and take a replacement module with it.

Storage, expansion and I/O faults

Storage and I/O symptoms

Symptom	Probable cause	Action
"Disk not present" for drive D:, or a card that vanishes mid-write	CompactFlash drawer: on some machines the plastic stops do not push the card firmly onto the contacts	Shim behind the card with a small piece of card as the drawer closes. Use nothing thick, and make sure it cannot come loose inside.
PC Card modem not recognised, or connects only at low speed	Current draw. Psion Teklogix give the Series 7 slot a 200 mA limit, against 800 mA on a late netBook. V90 cards are the worst, including Psion's own Gold Card	Force V34 by setting the modem's Data Init string to AT+MS=11 in the Control Panel. Winmodems need Windows and will not work.
PC Card works in a netBook but not in this Series 7	Expected: 200 mA on the Series 7, 300 mA on a netBook built before September 2002 and 800 mA after	Nothing to repair. The September 2002 board change matches the revision 10 board from week 35 of 2002.
Microphone records nothing, or intermittently	The microphone connection is a press fit and tends to fail	Pressing hard on the case above the microphone, near the right Shift key, often cures it for a while.
Serial port dead after using a serial mouse	A serial mouse powered from the port; one report describes burning out a Psion port this way	Do not power a mouse from the port. Use a self-powered device or a PC Card serial port.
External serial device will not talk to the machine	The Psion serial cable is a null-modem cable	Add a null-modem adapter when connecting a modem or GPS.

Resets

The reset hole is under the backup battery hatch.

Reset levels

Reset	Procedure	What survives
Soft	Press an unfolded paperclip gently into the reset hole until you feel a small click, then switch on without touching any keys.	Saved files. Changes to open files are lost, and some display, keyboard and Extras-bar settings revert.
Hard (Psion's method)	Remove all power sources: the mains adapter, the main battery and the backup battery.	Nothing. The internal disk is wiped.
Hard (quicker method)	With the machine on, press the reset hole until the screen goes off, then hold both Shift keys while switching on. A single beep, then the logo for about 10 seconds, then the demonstration files.	Nothing. The internal disk is wiped.

Repairability and parts

Repair options by part

Part	Repairable?	Notes
Screen cable seating	Yes	The most useful repair on the machine; Psion documented the fix.
Screen cable clamp	Not practically	Part of the motherboard. Breaking it while lifting it means a donor board.
Battery pack	Yes	Rebuildable with new 18650 cells. See Psion Series 7 Battery Service.
Backup cell	Yes	CR2032.
Keyboard	Yes	New-old-stock Series 7/netBook keyboards are sold as S7_KBD-UK, -DE, -FR, -ES and -NO. The keyboard is a sealed unit and should not be dismantled further.
Microphone contact	Yes	A press fit that can be reseated.
RAM (board level)	With SMD skills	Two unfitted DRAM sites. Use low-power parts; the DRAM is powered continuously.
ROM (personality) module	By replacement	A user-replaceable board carrying the boot loader and operating system. Pre-programmed Series 7 modules are sold. Reflashing one outside the machine is undocumented.
LCD panel	Donor only	No source of new panels is known.
NEC ASIC, Philips CPLD	No	Custom parts; a failure means a donor board.

Psion Digital stopped all repairs of its legacy range, including the Series 7, in June 2005. Psionex in Lincoln offers a Series 7 repair service.

Capacitors

No capacitor failure or recap is recorded for the Series 7 or netBook in the Series 7 FAQ's known-issues list or on PsionWiki. The hardware faults they document are the screen cable, the battery-catch microswitch, the CompactFlash drawer and PC Card current. Capacitor work is justified only by evidence on the board, such as corrosion from a leaked cell. See Capacitor Failure Symptoms and, for a comparable low-voltage surface-mount board, Psion Series 5mx Capacitor Replacement Guide.

Related pages

• Psion Series 7
• Psion Series 7 General Maintenance
• Psion Series 7 Battery Service
• Psion Series 7 User Guide
• Psion netBook Troubleshooting Guide
• Psion netBook Pro Troubleshooting Guide
• Battery Explosion, Capacitor or Corrosion Damage
• Recommended Tools