It's impossible to estimate from the distance what's wrong. I'd recommend to send in the module for repair if you have no experience
in electronics and soldering.

If you want to try the repair yourself: First of all I'd recommend to replace all integrated circuits. In most cases this solves the
problems. If this does not help I'd replace the transistors. If even this does not help the difficult part of the repair begins.

And please: turn off the system when you remove, install or swap modules !

Best wishes
Dieter Doepfer

> -----Ursprüngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com [mailto: Doepfer_a100@yahoogroups.com ]
> Gesendet: Dienstag, 9. Dezember 2014 01:07
> An: Doepfer_a100@yahoogroups.com
> Betreff: 1 A-108 Is 100% Silent
>
>
>
>
>
> Dear members,
>
> Technically I am so far with electronics, so I thought maybe you can help with this strange problem with my favorite filter A-108.
> I don't hear any any sound from the outputs, while the input is connected to the Saw of A-111; no click, no tick, no
> noise, just 100% silence, as if my whole setup is off. As if I'm on the top of Mount Everest.
>
> Some time ago, when replacing some modules, I touched a place on solder side near the Frequency potentio meter with the
> screwdriver, while the system was on. At once heavy agressive sparks rapidly appeared [not expected from such a 12V
> board], almost hit my face.
>
> The Frequency potentio meter was damaged and totally out of work. I only could change the frequency via the control
> voltage inputs. For the rest everything was fine.
>
> But since I took the damaged Frequency potentio meter out, I don't hear any sound anymore. It's 100% silence. The same
> after putting a new one.
>
> I did some measuring with these settings:
> With Sawtooth,
> A-111 Octave Switch at 0 (zero),
> A-108 Input Volume at 5,
> No CV's
>
>
> Results:
>
>
> From the power supply:
> -12V and +12V
> And the chips also get their power.
>
>
> From the input:
> DC = changing from -1V to +1V
> AC = 1.6V
>
>
> From CA3083Z: from IC4:
> pin1 (input) = 1V
> pin16 (input) = 1,5V
> pin15 (output) = 0,5V
>
>
> From TL084:
> All the inputs of their own circuits where equal. Sometimes the outputs where the same as their inputs.
>
>
> From BC 547:
> Q1 = 0,70
> Q2 = 0,69
>
>
> From the Outputs of the A-108: with DC measurement:
> 6db = 0,30V
> 12db = 0,15V
> 24db = 0,31V
> 48db = 0,06V
> BP = 0,09V
>
>
> From the Outputs of the A-108: with AC measurement:
> All Outputs = 0V
>
>
>
>
>
>
>
>
>