Oh dear! Guess you are going to have to make exhaustive comparative checks
between working and the non-working voice to get to the bottom of this one.
It would be interesting at this point to ensure C50 is OK and that the
filter cut off bias voltage at pin 13 of IC32 doesn¹t vary to wildly from
the others.
Cheers,
Andy
On 13/02/2010 07:27, "Alexis V. Rogers" <alexis.v.rogers@gmail.com> wrote:
>
>
>
>
>
> Q5 and Q6 are fine. I swapped out IC35 but the voice still doesn't sound when
> the VCA is set to EG mode. When set to gate mode, it sounds slightly lower in
> volume than the other voices and is a little flat. I'm stumped. I've also
> looked for a cracked solder joints to no avail.
>
> --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , Andrew
> Jury <andy@...> wrote:
>> >
>> > Check the none of the transistor have leaky junctions, but failing that
>> swap
>> > IC35!
>> >
>> >
>> > On 07/02/2010 21:02, "Alexis V. Rogers" <alexis.v.rogers@...> wrote:
>> >
>>> > >
>>> > >
>>> > >
>>> > >
>>> > >
>>> > > The LED does light on that voice. I checked voltages on IC35 and Q5 as
you
>>> > > suggested and found two discrepencies with the other working voices. I'm
>>> > > measuring -1.495V on pin 1 of IC35 on the problematic voice, where I get
>>> > > -0.02ish on pin 1 on the working voices. Also, I'm getting -1.2V on the
>>> base
>>> > > of Q5 where I'm getting around -0.02V on the bases of Q5 on every other
>>> voice.
>>> > >
>>> > > --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
>>> <mailto:PolySix%40yahoogroups.com> , Andrew
>>> > > Jury <andy@> wrote:
>>>>> > >> >
>>>>> > >> > Hi,
>>>>> > >> >
>>>>> > >> > When you switch to EG mode does this non-sounding voice still light
the
>>>> > >> LED?
>>>>> > >> > As a generic answer, you might want to perform some comparative
>>>> > >> measurements
>>>>> > >> > around bi-lateral switch IC35 and around emitter follower stage Q5
>>>>> with the
>>>>> > >> > other working voices. My guess is that there is a problem somewhere
>>>>> in this
>>>>> > >> > vicinity.
>>>>> > >> >
>>>>> > >> > Good luck and don¹t forget to tell us how you get on.
>>>>> > >> >
>>>>> > >> > Cheers,
>>>>> > >> > Andy
>>>>> > >> >
>>>>> > >> >
>>> > >
>>> > >
>>> > >
>>> > >
>>> > >
>> >
>> >
>> >
>> > [Non-text portions of this message have been removed]
>> >
>
>
>
>
>
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