>>Now for my question:  I've had a few LCD clocks that refused
>>to work after I replaced the battery.  My guess here is that
>>when the battery goes dead the internal circuits stop
>>oscillating, putting DC on the display, ruining
>>it for the next go.   Believable?
>
>No, the LCD runs on a charge pump driven by the battery (if 1.5V at
>least). No clock = no LCD voltage. Much more likely that there is gunk and
>dirt in the main board and the oscillator's self bias resistor is not
>enough to get it out of its stuck state.
>
>Also some early chips were bad enough that they self destructed in time
>(20+ years). I have a freind who collects stuff and I've seen a couple of
>strange items.  If unsure scope one of the xtal pins.
>
>Peter

I could believe that, because they are older, and they have the
chip-on-board (under the expoxy blob) so reliability probably
wasn't at the top of the design list.    Thanks for the
suggestion about looking at the crystal, though.

Barry

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