Psion Series 5 Memory Board -- Repair

The Psion Series 5 daughter board module is 79000-0014 Rev 2.3. It is double sided with 36-pins on each side, and usually has 6 MB of ROM memory. It also has the following integrated circuits.

• 3506-0081-02
• S5 Base V145
• 9837

• 3506-0091-02
• S5 UK V14
• 9832

This particular Psion unit had not been well looked after and it had damage to the hinges and screen cable. It also had an intermittent fault where sometimes it could not access all of its memory. I suspected dry solder joints as the manual suggests, however when I opened up the unit, I noticed it had a socket that had an uncanny resemblance to the ones I had seen in laptops. I had come across laptops that had intermittent issues registering all of their memory and it usually pointed to electrical connections between the memory socket and the memory module.

When I took the memory module out, (in the manual they call it the daughter board) I noticed that some of the pins had greenish oxide on them. Therefore, I used the same technique as I do when repairing laptops, which was to use a jet of air to remove any dust from the socket, and then use my ESD proof workbench to clean the contacts on the module using an electrical contact cleaner.

Once I returned the daughter board into its socket, and did a memory test, the problem was solved!

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