VIC-20 -- no sound

From: Lawrence Walker <lwalker_at_mail.interlog.com>
Date: Thu Sep 10 14:29:36 1998

On 11 Sep 98 at 0:38, Tony Duell wrote:

> The audio output circuit is quite simple. Sound comes from pin 19 on the
> 6560 VIC chip (UB7). It's filtered by C17 (0.01uF), R16 (1M) and C20
> (0.1uF) and fed to the base of Q5 (2N3904) which is connected as an
> emitter follower. The collector is tied to the +5V rail. The emitter load
> is R15 (470 Ohm). The emitter is also connected to the +ve side of C16
> (1uF), the other side of which goes to pin 3 of the monitor socket.
>
Interesting. The schematic I have in the Programmers Reference Guide is
obviously for a different model. The schema is c-writ 1980 and labeled
"Schematic Main Logic Version E"
Received on Thu Sep 10 1998 - 14:29:36 BST