Vintage Synth Repair

Andrew, The D5 has a membrane style plastic film for key contacts. Have 
you checked for dirt and/or corrosion between the film layers? I can 
look at the D5 in my shop if you need more details. It's been a while 
since I was inside it.
Let me know, Fran

--- In vintagesynthrepair@yahoogroups.com, "aent440" <andrew@...> wrote:
>
> Hi, the top 5 keys (intermittently) fail to sound on my D5. I can 
> always see a time multiplexed signal for each key on the main board 
and 
> can just about see a difference in pulse width when the second 
velocity 
> contacts come in (but not as pronounced as for the working keys). I 
> have a paper copy of the service manual but it does not describe the 
> keyboard. Does anyone have a description or schematic of the keyboard 
> operation please? Thanks in advance, Andrew.
>