Max Sentry wrote:

> Can someone explain the wiring to a 707 if I have both 707 and 727
> sound eproms and want to switch between the 2 sound banks with a switch
> mounted on the outside of the box Is there a schematic for this mod
> posted somewhere

It should be simple enough, but check the overall sanity of this idea
with the circuit diagram first!

You should be able to replace the ROMs with one twice the size. This
will give you an additional address pin. Blow the ROM with the 707
samples and the 727 samples by joining the two images together.

Now, replace the existing sample chip with your new super-twice-the-size
sample chip, but leave the extra address pin bent out of the socket.
Solder a resistor (about 4.7k ought to do, but anything from about 1k to
about 10k will be fine. Actually, nearly anything will be okay, but try
and stick between these values). This will pull the pin high, forcing
the chip to read from the upper half. Wire your switch between the
address pin and ground, so it's closed when you want the lower half.

Simple.

Gordon