I did find a chip pulling down DB4 on U311 it
is a 6514 4K CMOS RAM. Thank god for IC sockets. The only problem I'm a
little confused on a cross for it. It appears obsolete. It is called D444C
on the chip and 6514 on schematic. Can anyone offer advice on a
cross.
----- Original Message -----From: fsimon100Sent: Friday, May 30, 2008 8:58 AMSubject: [vintagesynthrepair] Prophet 10 deadWas curiouse if anyone can offer help. I bought a dead P10 no lights
or anything. The processor is good. I put logic analyzer on decoder
output and see ROM1 (Y0) and RAM (Y5)(which I believe is the scratch
pad memory)active at start up. All address buses and Data buses are
active. I am not certain the algorithm. A flow chart would be nice or
some help with what I should see at some critical points. I am
wondering if there is a chance the ROMs lost programming and how would
I know. Even if they did shouldn't lights and/or display come on. And
yes the power supplies are good.