Analogue-sequencer

Colin/all,

> Since the other pots on the same multiplexer are working, and the
> multiplexer is working, the problem has to lie in the pot, or the
> connection from the pot to the multiplexer.
> Make sense ?

just a thought..
I had a problemw tih mine, it kept showing step9, as constantly changing.
I couldn't adjust any of the other values and it just showed '9' all the
time..
I resoldered the pot, swapped the 4051, it STILL did it..
The I discovered that I had not put the connector from the pot boards to
the motherboard correctly...
Fixed this and bingo, life was good again...

Paul

Robert,

> Ah. Correctly how? You mean the polarity was wrong? Or did
> you just had to push in better?

hehe, nah, I had them all out one pin (connector was shifted across)
But I would double check the connection to the IDC connector, make sure
its all ok. Perhaps even meter the IDC cable.

Paul

> Colin, what about bad flat cables? Do the signals of pot #9
> and #13 run next to each other in one of the cables?

The signals from 8 pots are multiplexed onto a single line - that's what
each of the 4051s do.
They have 8 inputs, with a pot connected to each, and a single output.
The input that is connected to the output is selected by a 3 bit address.
Each multiplexer output then runs down the ribbon cable to the main board,
where another multiplexer selects from up to 6 pot multiplexers, or the data
and tempo pots, and feeds that to the ADC.

Since the other pots on the same multiplexer are working, and the
multiplexer is working, the problem has to lie in the pot, or the connection
from the pot to the multiplexer.
Make sense ?

Cheers,
Colin f



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On Monday 19 January 2004 15:12, Colin f wrote:

> Since the other pots on the same multiplexer are working,
> and the multiplexer is working, the problem has to lie in
> the pot, or the connection from the pot to the
> multiplexer.
> Make sense ?

Yup.
I'll do some more testing with the other pots. If I get 
similar results with other pots, of if pots other than #9 
or #13 somehow have influence on the problem, we may have 
something else going on.

You're a probably right, it's just that I have a hard time 
believing that two pots are gone. Maybe a bad batch...

- Robert

On Monday 19 January 2004 15:22, Paul.Maddox@synth.Net 
wrote:

> just a thought..
> I had a problemw tih mine, it kept showing step9, as
> constantly changing. I couldn't adjust any of the other
> values and it just showed '9' all the time..

Looks like my problem!

> I resoldered the pot, swapped the 4051, it STILL did it..
> The I discovered that I had not put the connector from
> the pot boards to the motherboard correctly...
> Fixed this and bingo, life was good again...

Ah. Correctly how? You mean the polarity was wrong? Or did 
you just had to push in better?

- Robert