Analogue-sequencer

> the 62256 RAM IC's arrived this morning and i replaced them, but no
> change...so the last thing i'm now waiting for is the ds1210 battery
> backup circuit. so by now i've resoldered & quadruplechecked all
> solderpoints on the mainboard and replaced just about all IC's on it
> with new ones. i have to admit i'm starting to think about just
> giving up and using the thing as a really expensive nightlight.. :(

Hi Chiel,

You could bypass the backup controller temporarily to test whether it is the
problem.
Take it out the socket, and just jumper a wire from the +5v supply to the
Vcc supplies on the RAM chips. This would be a wire from pin 1 to pin 8 of
the DS1210 socket.

If you still can't get it working, you can ship the main board to me and
I'll check it out thoroughly on the scope/logic tester.
If all other ICs have been ruled out, it's possible there could be static or
shock damage to one of the CPU lines.
Have you checked continuity of all the CPU, decoder, DS1210 and SRAM lines
against the schematic, with the ICs removed ? Maybe there could be a broken
track ?

Cheers,
Colin f