Psion Workabout mx Troubleshooting Guide
Fault-finding for the Psion Workabout mx, and for the Workabout rf, which the same service manual covers. Psion's Workabout MX Service Manual has a fault table, option port tests and the current limits Psion's final test applied to every unit.[1] Its cure for a main board fault is a replacement board, with the faulty one returned to Psion. Cell handling, the fuse and dismantling are on the Psion Workabout mx General Maintenance page.
Before you start
[edit | edit source]- Back up the data if the machine still works.[2]
- Fit fresh AA cells or a charged pack, and check the CR1620 backup cell.[2]
- Check the fuse beneath the main batteries: 1.25 A fast blow, 5 × 20 mm.[1]
- Expect a reboot after a backup cell has been changed: the Workabout beeps and shows the shell screen after up to five seconds.[1]
Fault table
[edit | edit source]The causes and cures below are Psion's, from the service manual.[1]
| Fault | Causes, in Psion's order | Cures |
|---|---|---|
| Will not boot | Flat or faulty batteries; main board; fuse; battery contacts | Replace alkalines or recharge the NiCd pack; take the internals out and check the main power flexi ZIF connector; check and replace the fuse; check the battery contacts and main flexi for continuity with a meter |
| Switches off when used | Damaged main power flexi | Replace the drawer assembly |
| Lines on the LCD, or blue patches | Damaged LCD; LCD ZIF connector open; main board | Replace the LCD; strip to the chassis assembly and close the ZIF; replace the main board |
| Cracked LCD glass | Broken glass | Replace the LCD |
| Backlight does not work | Backlight; main board | Replace the backlight; replace the main board |
| Backlight dim | Worn backlight: about 500 hours to half brightness | Replace the backlight |
| Alphanumeric keys not working | Damaged key mat; main board | Replace the case; replace the main board |
| LIF communications fail | Main board | Replace the main board |
| SSDs cannot be read | Warped connector block arm; faulty main flexi; damaged door switch on the main board | Replace the connector block; replace the drawer assembly; replace the main board |
| No top port, TTL or barcode communications | Damaged expansion flexi; warped connector block arm; loose ZIF connector; damaged door switch | Replace the drawer assembly; replace the connector block; reseat the expansion flexi and close the ZIF; replace the main board |
| No infrared communications | Top or bottom IR port damaged | Replace the drawer assembly; replace the bottom IR port flexi |
| NiCd pack will not charge | Central contact not connecting; damaged battery contacts; damaged pack; charger | Replace the drawer assembly; replace the pack; see the Docking Station Service Manual, Psion part no. 6104-0004-01 |
| Drawer will not close | Drawer derailed; obstruction; damaged drawer lock | Refit the drawer; look for misplaced cells, contacts, SSDs, flexis or seals; replace the case |
| Drawer will not open with the release button | Drawer derailed; damaged release button; obstruction; missing drawer spring | Refit the drawer; replace the case or drawer assembly; remove the obstruction; fit a drawer spring |
| Drawer will not stay closed | Obstruction; damaged lock | Remove the obstruction; replace the case or drawer assembly |
| Damaged case, key mat or window | User damage | Replace the outer case, with labels matching the old one |
A damaged door switch on the main board appears in the table as a cause of SSD and option port faults.[1]
Current checks
[edit | edit source]Psion's final test powers the Workabout through its LIF connector from a test unit with an ammeter in the battery circuit.[1]
| State | Limit |
|---|---|
| Battery standby current, 2 MB unit | Fail if above 750 µA |
| Running, test program loaded | Fail if above 25 mA (mx) |
| On external DC power | Battery current should read zero |
The same test checks the screen pattern, the backlight, the contrast range from black to clear, every key, the buzzer and the battery ground contact.[1]
Testing the option ports
[edit | edit source]Psion's checks use the built-in Comms application.[1]
| Port | Setting | Test |
|---|---|---|
| RS-232 | Port A (RS-232/TTL module) or B (RS-232/barcode module), 9600 baud | Connect a null-modem cable to a PC running a terminal program; characters typed on either end should appear on the other |
| TTL | Port D for true data, G for inverted, 9600 baud | Scan at least two different barcodes with a TTL scanner; the number appears at the top left of the screen |
| Barcode wand | Port E, 9600 baud | Scan at least two different barcodes with the wand |
The switched 5 V supply on the option connectors (VCCEXT) comes on only when the port is opened. It gives up to 200 mA, 4.7 V minimum, and limits at about 250 mA, so a peripheral drawing more will not run.[1]
Charging and the LIF converter
[edit | edit source]The LIF converter carries the mains adaptor supply and the serial link into the Workabout and contains the charger, a linear regulator in constant-current mode.[1] If a pack will not charge, check the central contact and the battery contacts in the drawer before condemning the pack or the docking station.[1] Charge packs only with Psion peripherals.[2]
Related pages
[edit | edit source]- Psion Workabout mx
- Psion Workabout mx General Maintenance
- Psion Workabout mx Documentation
- Psion Workabout Troubleshooting Guide
- Battery Explosion, Capacitor or Corrosion Damage
References
[edit | edit source]- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Psion Enterprise Computing Ltd, Workabout MX Service Manual, part no. A6124-0002-02, version 2.0, May 2000. Hosted as File:Psion Workabout MX Service Manual (May 2000).pdf. Introduction (p. 1), troubleshooting table (pp. 4-6), fuse (pp. 11 and 18), option checks (pp. 19-20), expansion interfaces (pp. 21-23), LIF converter (p. 23), final test (pp. 24-27).
- ↑ 2.0 2.1 2.2 Psion Industrial PLC, Workabout mx and Workabout rf User Manual, 1998. Hosted as File:Psion Workabout mx and Workabout rf User Manual (1998).pdf. Power and battery information (p. 18).