Wyse WY-520 problem (OT?)

Not sure if the WY-520 is off-topic or not, I've no idea how old it is... In case it is on topic, I'll ask anyway :) I've a WY-520 here, which won't keep its settings if turned off for more than a certain (undetermined) period of time. I'm guessing there should be a battery backup in it, which has gone flat. Is this a user servicable item (i.e. can I change the battery, even if I need to do soldering)? If so, how does one remove the back without destroying things? I've undone the one visible screw, but the back resisted my attempts to release it, and I don't want to force it in case I break something - any tricks? TIA, Ade. -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.344 / Virus Database: 267.10.15/82 - Release Date: 25/08/2005