Re: Rubywand - Mockingboard schematic

[mjmahon@aol.com (Michael J. Mahon)]

Linards Ticmanis wrote:

>Patrick Schaefer <PSchaefer@epost.de> wrote in message
>news:<3DA5C5B4.DAD417BA@epost.de>...
>
>> 5k means 5kpF=5nF. 5K can also mean 5pF with Type K dielectric (with a
>> certain temperature coefficient). Looking at the schematic I would guess
>> 4.7nF.
>[...]
>
>> You can use any of these phi2-generating circuits instead. E.g.
>> NOT(NOT(phi0) OR Q3), built using 1/2 74LS02.
>
>Well, simply removing the capacitor in question solved the problem.
>Now everything works just fine. Adding a pair of diodes which allow
>the RESET signal to get through to the sound chips solved the problem
>of the card braying on after you stop a program with the RESET key,
>too. Now the only remaining question is, which Software, beyond a
>couple of "Ultima"s, actually supports the card?

The capacitor should be a 5pf capacitor, just to slow the edge and
provide a little more setup time for the clocked signals.

Apparently, you have fast enough 6522's that its working without
the 15-20 nanoseconds extra delay provided by the capacitor.

(BTW, I published a one page article in Call A.P.P.L.E in the
mid-80's about adding a diode or two to reset the sound chips!  ;-)

Glad to hear it's working!

-michael

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