Maker Pro
Maker Pro

TECH: 1702a Eprom Voltages

Hi All,

I have in a 1978 model pinball machine, one 1702a.

I would like to backup it contents, but my eprom programmer works with
2716 and later.

My question is -

When I probe the cpu board with a scope, around the eprom, I was
expecting to find 5, -5 and -12.

I only find +5 and -12.

Can I power this device from an external -12 and make a adapter to then
read its contents like a 2716.

I can then program a 2716 and using a couple of sockets, rewire for the
2716 in place of the 1702a.

Any help appreciated.

Kind Regards, Garry