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Subject: Re: [PolySix] Non-working attenuator

From: Bob Grieb <bobgrieb@yahoo.com>
Date: 2014-12-23

Hi,

   I think we have been looking in the wrong place.    Probably the switch and sensing of
it are fine.   As you mentioned, we should focus on IC35 outputs, and the circuitry that
they control on the chorus board.   I think you should see the same values on IC35 as on the switch,
0-10 if that is what you found.   Regardless, the voltage at point "I" should be changing
when you move the attenuator switch.   Please check that, and if that is changing, tell us
what it is, then you need to see if that is getting to the chorus board.  Then we can take it
from there.

 What 7408 are you talking about?

     Bob

From: "tuk88@rocketmail.com [PolySix]" <PolySix@yahoogroups.com>
To: PolySix@yahoogroups.com
Sent: Tuesday, December 23, 2014 12:27 PM
Subject: Re: [PolySix] Non-working attenuator

 
Thank you for your answer Bob !

When I say attenuator doesn't work, that means that turning the knob has no effects on sound (no increasing or decreasing sound).

The differents functions driven by P10, P11, P12 and P13 work well (effects and an other one).

I check between the different pins of the connector and change the attenuator position. I've got a binary counting from 0 to 10 (considering 1 when short circuit done by diode, and 0 by open circuit). So I think the panel doesn't have any problem.

I check the presence of D03 on the different chip by directly touching the pin IC. D03 is present where it should be.

I'll try to find an oscilloscope to check the good signal of D03.

Maybe I've got a 4042 or 7408 out of service ? I think I'll try to change them.

What do you think ?

Lucas