[sdiy] Prophet 5 memory problem

[Oakley Sound]

Unfortunately, it could be any component that is connected to the 
digital busses that could be making the instrument misbehave. It is 
unlikely to be the battery since this is has no effect on the operation 
of the circuitry while the synth is powered up.

The usual suspects are the RAM chips. But a look on the data bus and 
address bus will reveal a problem. A scope is useful for this job but a 
logic analyser can be better. Generally a fault on the data/address 
lines will show up as neither a logic high or logic low. Even so, it can 
still be a case of swapping chips until the problem goes away. Bad 
inputs can pull down whole output lines, but one bad output can prove 
troublesome to find. If you are lucky the errant chip will be getting 
warm to touch.

It's probably not this but that ribbon cable that joins the two front 
panel boards together can do all sorts of weird stuff when it goes bad. 
Pushing down on the front panel can usually instigate an obvious fault 
if this is the case though.

Tony

www.oakleysound.com