Hi Paulo,
Yes, afraid to say this is what I used to do when I first started repairing
Polysix. Changing just about every IC in the hope that it would fix the
problem. After the first six or seven you start to realize that these types
of whacky fault are almost exclusively down to o/c tracks. Get yourself a
logic probe and check all the points where the data bus (D00-D07) terminates
and make sure you have pulse trains on these lines. Bet you one or more of
them do not terminate.
You asked if any components are traditionally¹ associated with this type of
problem? Yes, o/c tracks. If this board is causing you real issues and is
severely damaged then I would recommend you seek out the parts and build
yourself a clone. You won¹t regret it.
Cheers,
Andy
On 03/11/2010 19:13, "Paulo" <inocencio66@yahoo.com> wrote:
>
>
>
>
>
> Yeah sorry I realize pctech333 is dealing with an old 367a as well.
>
> Well this Polysix I´m trying to restore had the battery leakage problem, which
> I repaired following Old Crow´s instructions. I rewired the traces, installed
> a new nimh battery and new ICs 30 and 31. The programmer now seems to work,
> but when I try to reset the dac only leds 4 and 8 light up.
>
> This synth had also the other problem from the beginning: none of the pots
> work, just the switches. For instance, I can select any effects mode, but the
> speed/intensity doesn´t make any changes. Likewise, vco octave works but pwm
> doesn´t, and so on.
> The exception is MG not working in any way, with the led constantly lit.
>
> I already changed the 4560 chip, which I think is the dac buffer, for a tl072.
> And ic20 and 21 with LM13700. I don´t have a scope yet, so that´s probably the
> last ic swap for now. Well, maybe IC6...
>
> There must be some component that´s "traditionally" known for this
> malfunction. I don´t think it´s the memory nor the CPU. Maybe it´s the DAC?
>
> Cheers,
>
> Paulo
>
> --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , Andrew
> Jury <andy@...> wrote:
>> >
>> > Hi,
>> >
>> > Sorry, I must be missing a post here, this isn¹t making any sense. Can you
>> > describe the exactly problem with the 367? I may well be able to help you
>> > with this...
>> >
>> > Cheers,
>> > Andy
>> >
>> >
>> > On 03/11/2010 15:37, "Paulo" <inocencio66@...> wrote:
>> >
>>> > >
>>> > >
>>> > >
>>> > >
>>> > >
>>> > > Hi,
>>> > >
>>> > > I´ve got the exact same problem with an old 367a.
>>> > >
>>> > > Can someone help, please?
>>> > >
>>> > >
>>> > >
>>> > >
>>> > >
>> >
>> >
>> >
>> > [Non-text portions of this message have been removed]
>> >
>
>
>
>
>
[Non-text portions of this message have been removed]