I tried a different ribbon cable, a different bus connection point,
tried the lower bus strip in the case, and checked the ribbon and the
bus connector on the module and cannot see any obvious faults. Both
the +12 and -12 led's are on in the case.

I'm stumped.

TJ

--- In Doepfer_a100@yahoogroups.com , <yahoo@...> wrote:
>
> > Hi Dieter
> >
> > > I cannot imagine a fault that causes distortion and that is not
> > caused by
> > > the two integrated circuits. These are the only active parts in
> > the module.
> > > Anyway - we will see what is wrong if the module comes back to
us for
> > > service. Maybe the 1000u AC coupling capacitor in the amplifier
> > output is
> > > defective. In any case the repair is covered by warranty.
> > I know funny distortions from opamps driven by an asymetric power
> > supply: Maybe a broken wire in the power ribbon cable, or cold/broken
> > solder joint at the bus connector of the module. Both could be
caused by
> > the frequent removing of the module.
> >
> > Florian
>
> You are right. An asymmetric power supply could cause this
behaviour. TJ:
> please double check if the other modules on the same bus are OK (an
> assymetric supply caused by the power supply would affect other
modules too)
> and if the two LEDs for +12V and -12V on the bus board light up. If
that's
> OK please use another bus connection cable to find out if the cable
causes
> the problem. And have an eye for the bus pin header of the A-199 module.
> Maybe one of the pins is broken or the solder on the bottom side is
not OK.
> And try also another connector of the bus board (maybe the pin
header of the
> bus board causes the problems).
>
> Good luck
> Dieter Doepfer
>