It was the IC31...
(but i changed the battery too...)
at
--- In PolySix@yahoogroups.com, "atuzzi" <antoniotuzzi@t...> wrote:
>
> Ok,
>
> The card seems ok,
> The battery is the old style VARTA, but is not leaked (til
> yesterday...). Proabably is the second or (I hope) the third one
> (changed in 1998 maybe)
>
> The P6 is outputting sounds, all the voices are working, and the
adsr
> can be modified and the filter and resonance too (Keyboard tracking
> too).
>
> but is not changing:
>
> Waveform, Octave 4 8 16, pwm, sub osc mode, lfo destination and
> effect type.
> (all digital paramenters?)
>
> +
>
> modyfing the intesity of the effects is acting on the LFO speed.
>
> +
>
> effect number 3 goes in "mute mode (no sound at all).
>
>
> all the analog parameters are changing (I checked with a
voltometer).
>
> I checked all the traces and vias with ohmeter (full conductivity,
no
> resistence.
>
> My question:
> can be the the IC31 the culprit ? What's the exact function of the
> 74ls08 in that point ?
> a broken ic31 can affect the parameters I described ?
>
> can a 74hct08 can be used instead of the 74ls08 ?
>
> Thank you
>
> Antonio