mixer glitches

The Tascam TM-D4000 I'm currently using after the Yamaha 4416 went back to Chennai for repairs, showed its temperamental nature a couple of days back on Tuesday, when it "hung" with blank display and saturated output - all inputs set to +10 dB or something like that. This happened 10 minutes after switching it on around 4 pm. So, the reason S used to report this in the Studio is probably not water condensation. Turning it off and on does not work, have to wait an hour or so. After an hour, turning it on - worked, again hanging after 7 minutes. Turned it off till Wednesday, then it worked fine. No problems yesterday and this morning, either. But must be ready with a backup plan, since this sort of failure is a possibility.