Several years ago I bought a Psion Revo, or Diamond Mako, as this particular version was called. The Psion Revo is a very nicely made keyboard based PDA, with an apparently significant design flaw in its battery charging technology.
Several years ago I bought a Psion Revo, or Diamond Mako, as this particular version was called. The Psion Revo is a very nicely made keyboard based PDA, with an apparently significant design flaw in its battery charging technology. The battery problem caused the machine to be unable to accept a full charge whereupon the machine would only operate for a few minutes before failing through lack of energy. I have had the machine locked in a draw for several years but finally decided to liberate it and give it one last chance to be useful. First I tried charging the Revo, the indicator for rapid charge didn't come on, so the problem was still present although the battery must after many years of neglect, have been completely flat. I decided to consider replacing the rechargeable AAA cells inside the machine. I followed the instructions posted at "http://www.r3uk.com/index.php/tech-tips/34-disassembly-guides/3-psion-revodiamond-mako-disassembly-and-battery-replacement". The instructions are easy to follow, and soon I had removed the battery pack. However, I didn't have any new batteries to solder together, so I decided to give the old battery pack one last try. I snapped he connector back together, and with everything hanging together outside the case, I tried the charger one more time. This time the rapid charging light came on and stayed on for many hours. I left the machine charging away overnight, and came back to find that the machine was trickle charging as the designers had intended. So, I now suspect that the problem with Revo charging was caused in part by a poor battery connector. That was the only thing that changed between my first attempt to charge the unit and the second successful attempt.
Sadly Psion no longer make PDAs. If they had continued making machines based on the 'SIBO' technology of the Series 3a machines, everyone in the world would have been using them for the last decade. But Psion gave up their technological lead and converted to a more complex beast - such is progress. Even so, I will be a happy camper if the Revo keeps on charging correctly.
I have loaded the machine up with various interesting pieces of software saved for many years after my original skirmish with the machine. There is a sketching/paint program (as the Revo has a dainty stylus this makes much sense). There is a program for logging time spent on projects ('Worktime') and a program that I wrote which lets you make connected box type diagrams - which is a lot of fun - even if the screen is rather small.
I have not seen anyone else complain of the battery connector on the Revo. Perhaps my example is just a one off. I should have been a little suspicious of the fact that the connector is glued together. Why do you need to glue a connector if that particular part of the design is not under mechanical stress? But perhaps Psion knew that there was a problem with the connector not being able to pass relatively high charging currents, and were trying to work around the problem by getting the connector to work as well as possible by bringing its two halves into a quasi-pressurized relationship. We may new know. I have reassembled the Revo without any glue on the connector and I will be monitoring its charging and other characteristics. I am having fun using it - even if it was not a Psion 3a, it was a great PDA - what a shame about the reliability problems.