Hi Tim,

both chips, 555 and TL084 are working properly. also the
potentiometers seem to be ok. atm i am measuring V inbetween 2 boards
having the same settings. lets see what i find.

thanks


--- In Doepfer_a100@yahoogroups.com , "Tim Stinchcombe" <timothy@...>
wrote:

>
> Hi Helitron, Florian,
>
> > properly on there, and since it was working before it has to be some
> > component that is dead. guess i have to exchange the potentiometers.
>
> I'd be very surprised if changing any pots cures the problem, and
> besides, you could probably check that sustain pot is OK more easily
> by getting the envelope in a 'working' state (you seemed to suggest
> that was possible some of the time), and check the voltage at the pot
> wiper when in 'decay', so see if it varies much - should be something
> like close to 0V to around 8V maybe (looks like a 10k pot from
> Florian's photo).
>
> I don't have that module, so I don't know the full details of the
> circuit and how it works, but from the photos Florian posted I'm
> guessing IC2 must constitute 'logic' which is controlling the 555,
> and that is where I suspect the fault will be. If the chips are
> socketted ( ), a reasonable tactic would be to take the chips one at
> a time from the bad section (EG3), and try them in one of the good
> sections - if the good section continues to work, the chip is good,
> if not then you have id'd a bad chip. (If you put the chips from a
> good section into the bad the one, there is a small chance that the
> fault in the bad section might trash the good chip...)
>
> I can't quite make out the IC2 designation on the layout photo, but
> it looks like it could be simply a quad op amp chip (TL084/064 ),
> perhaps used as comparators, but that doesn't quite tie-in with
> the 'JPx' ( ) boxes on the schemo, which control the re-triggering
> and the 'reset' pin of the 555. And reading the manual, on page 2,
> that the 'end of decay' switches at the sustain level setting, I
> suggest that what ever causes this is what is mucking things up!
>
> Tim
>