Yes, it seems we can get three different static DAC values, but I am not sure that
is enough to calibrate the anti-log circuit. I tried the test, and saw roughly 0,2.5 and 5V
on the output of the DAC. I pressed lots of front panel switches. Other ones also affect the voltage, but it seems there are only three choices. Seems like you would want more voltages, and specific ones that were chosen for the job. The circuit in the Monopoly that is being adjusted is not logarithmic, it seems. Just a gain stage.
is enough to calibrate the anti-log circuit. I tried the test, and saw roughly 0,2.5 and 5V
on the output of the DAC. I pressed lots of front panel switches. Other ones also affect the voltage, but it seems there are only three choices. Seems like you would want more voltages, and specific ones that were chosen for the job. The circuit in the Monopoly that is being adjusted is not logarithmic, it seems. Just a gain stage.
From: Malte Rogacki <gacki@gacki.sax.de>
To: PolySix@yahoogroups.com
Sent: Friday, February 28, 2014 5:57 PM
Subject: Re: [PolySix] RE: Polysix tuning difficulties.
To: PolySix@yahoogroups.com
Sent: Friday, February 28, 2014 5:57 PM
Subject: Re: [PolySix] RE: Polysix tuning difficulties.
At 14:27 Uhr -0800 28.02.2014, Bob Grieb wrote:
That's exactly what the MonoPoly does!
The Monopoly service manual however gives
0.000V Down Low Adjust
5.250V Normal Mid Adjust
10.583V Up Hi Adjust
and takes the signal after the demultiplexer (and after the buffer and
possible a 100R resistor).
The octave switch in the Polysix should theoretically do the job.
> Found this on the web:
>
> "The other test mode is started by jumpering pins DB7 and P17 using a
>diode (cathode towards DB7) on the
> 8049 processor on the KLM-366 circuit board (this can be done on the
>keyboard connector CN04). In this mode the
> CV DAC is set to generate 0V, 2.5V, or 5V depending on the position of
>the OCTAVE switch (16' results in 0V, etc.).
> This mode is used to check the CV DAC and is not described in the service
>manual."
>
>
> I wonder if this could be used to set up the antilog circuit? Or
>possibly once in this mode, there are
> other voltage settings as well? Think I will try this out.
That's exactly what the MonoPoly does!
The Monopoly service manual however gives
0.000V Down Low Adjust
5.250V Normal Mid Adjust
10.583V Up Hi Adjust
and takes the signal after the demultiplexer (and after the buffer and
possible a 100R resistor).
The octave switch in the Polysix should theoretically do the job.