Discussion about the Korg PolySix synthesizer

I've been trying to help my friend repair his P6 which
was the victim of nicad leaks once again. 

I've carefully replaced and verified all of the traces
but I'm still having an interesting problem.

The ENV and VCF controls behave normally.

However, there is no response from:
OCT 
WAVEFORM
PW/PWM
SUB OCT
LFO MOD
FX MODE 
SPEED/INTENSITY 

I am thinking that the problem lies in the output part
of the DeMux and was curious what the relevant CMOS
chips were for the signals that aren't showing up.

cheers! [w]

Hi Wayne,

> I am thinking that the problem lies in the output part
> of the DeMux and was curious what the relevant CMOS
> chips were for the signals that aren't showing up.

I'll take it you haven't seen the schematic for this board? The CMOS 
logic types are clearly marked on the diagram. If you don't have it 
we can easily point you in the right direction of a copy. Some of the 
problems you mention are in the area of the IC19 (4051), but some are 
mearly switch functions and under control of the latches IC28/9 and 
IC34/5 (4042). Therefore I would suggest that you check the 
continutity of the tracks running from the mask rom (8048) P20-P27 
and the memory address bus DO0-DO7. Pay particular attention to port 
line P25 as it runs directly under were the battery has exploded. I 
find the best way to perform continutity tests is to print out the 
diagram and mark off the areas of track checked with a highlighter 
marker. If you want any comparative voltage / scoep waveform reading 
let us know.

Let us know how you get on and if you still can't get anywhere then 
see post 1934.

Cheers,
Andy

--- In PolySix@yahoogroups.com, Wayne Griffin <ingsoc_1979@...> wrote:

>
> I've been trying to help my friend repair his P6 which
> was the victim of nicad leaks once again. 
> 
> I've carefully replaced and verified all of the traces
> but I'm still having an interesting problem.
> 
> The ENV and VCF controls behave normally.
> 
> However, there is no response from:
> OCT 
> WAVEFORM
> PW/PWM
> SUB OCT
> LFO MOD
> FX MODE 
> SPEED/INTENSITY 
> 
> I am thinking that the problem lies in the output part
> of the DeMux and was curious what the relevant CMOS
> chips were for the signals that aren't showing up.
> 
> cheers! [w]
>

It's either in the files section on this lists website on yahoo, or
there is a link to it in the section which goes to my website.

On Sat, Jan 17, 2009 at 10:09 AM, Andrew Jury <andy@networkjabber.com> wrote:
> Hi Wayne,
>
>> I am thinking that the problem lies in the output part
>> of the DeMux and was curious what the relevant CMOS
>> chips were for the signals that aren't showing up.
>
> I'll take it you haven't seen the schematic for this board? The CMOS
> logic types are clearly marked on the diagram. If you don't have it
> we can easily point you in the right direction of a copy. Some of the
> problems you mention are in the area of the IC19 (4051), but some are
> mearly switch functions and under control of the latches IC28/9 and
> IC34/5 (4042). Therefore I would suggest that you check the
> continutity of the tracks running from the mask rom (8048) P20-P27
> and the memory address bus DO0-DO7. Pay particular attention to port
> line P25 as it runs directly under were the battery has exploded. I
> find the best way to perform continutity tests is to print out the
> diagram and mark off the areas of track checked with a highlighter
> marker. If you want any comparative voltage / scoep waveform reading
> let us know.
>
> Let us know how you get on and if you still can't get anywhere then
> see post 1934.
>
> Cheers,
> Andy
>
> --- In PolySix@yahoogroups.com, Wayne Griffin <ingsoc_1979@...> wrote:
>>
>> I've been trying to help my friend repair his P6 which
>> was the victim of nicad leaks once again.
>>
>> I've carefully replaced and verified all of the traces
>> but I'm still having an interesting problem.
>>
>> The ENV and VCF controls behave normally.
>>
>> However, there is no response from:
>> OCT
>> WAVEFORM
>> PW/PWM
>> SUB OCT
>> LFO MOD
>> FX MODE
>> SPEED/INTENSITY
>>
>> I am thinking that the problem lies in the output part
>> of the DeMux and was curious what the relevant CMOS
>> chips were for the signals that aren't showing up.
>>
>> cheers! [w]
>>
>
>
>
> ------------------------------------
>
> PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6Yahoo! Groups Links
>
>
>
>



-- 
.sig
-Chromatest J. Pantsmaker
http://www.chromatest.net