Doepfer

hi all,

one of the four EGs is not working properly:
when the sustain = 0, the output is high, without beeing triggered.
however, when a trigger/gate is applied, the envelope stops for the
duration of the signal, and then it goes high again.
with sustain >3, the envelopetriggering behaves normally, but the
output is too low compared to the other EGs on the module.
additionally, decay and relese also affect the triggering behaviour.

acually, i like this - makes nice envelopes, but still id like to know
where the problem may be.

thanks for any help.

> hi all,
>
> one of the four EGs is not working properly:
> when the sustain = 0, the output is high, without beeing triggered.
> however, when a trigger/gate is applied, the envelope stops for the
> duration of the signal, and then it goes high again.
> with sustain >3, the envelopetriggering behaves normally, but the
> output is too low compared to the other EGs on the module.
> additionally, decay and relese also affect the triggering behaviour.
>
> acually, i like this - makes nice envelopes, but still id like to know
> where the problem may be.
>
> thanks for any help.

If it's EG #4 (the lowest one) it may be a mechanical problem (short circuit
anywhere between the lower pc board and the metal frame). You could solve it
with adding any isolation material (e.g. self-adhesive tape) to the metal
part of the frame. Otherwise the EG in question is defective and has to be
repaired (probably a defective rotary potentiometer). In this case please
return the module to the representative or dealer where you purchased the
module. If it's still within the warranty period the repair is free.

Best wishes
Dieter Doepfer

its the EG#3, and the malfunction is also outside of the case. however
i will exchange the pot to see if that helps - since warranty time is
over. thanks !

--- In Doepfer_a100@yahoogroups.com, <hardware@...> wrote:
>
> > hi all,
> >
> > one of the four EGs is not working properly:
> > when the sustain = 0, the output is high, without beeing triggered.
> > however, when a trigger/gate is applied, the envelope stops for the
> > duration of the signal, and then it goes high again.
> > with sustain >3, the envelopetriggering behaves normally, but the
> > output is too low compared to the other EGs on the module.
> > additionally, decay and relese also affect the triggering behaviour.
> >
> > acually, i like this - makes nice envelopes, but still id like to know
> > where the problem may be.
> >
> > thanks for any help.
> 
> If it's EG #4 (the lowest one) it may be a mechanical problem (short
circuit
> anywhere between the lower pc board and the metal frame). You could
solve it
> with adding any isolation material (e.g. self-adhesive tape) to the
metal
> part of the frame. Otherwise the EG in question is defective and has
to be
> repaired (probably a defective rotary potentiometer). In this case
please
> return the module to the representative or dealer where you
purchased the

> module. If it's still within the warranty period the repair is free.
> 
> Best wishes
> Dieter Doepfer
>

Hi Florian,

thanks for the hint. you mean JP5? that looks properly soldered, like
all other solderjoints on the board.
and retriggering via LFO while holding down the gate, does retrigger.
however it depends on the sustain/decay pot settings. if both are low
the EG goes low when the retrigger signal goes high. if decay/sustain
are high (>3) then it retriggers.
however the overal env voltage seems low since the LED is quite dimm.

hel

--- In Doepfer_a100@yahoogroups.com, Florian Anwander
<Florian.Anwander@...> wrote:

>
> Hi helitr0n
> 
> 
> > one of the four EGs is not working properly:
> > when the sustain = 0, the output is high, without beeing triggered.
> > however, when a trigger/gate is applied, the envelope stops for the
> > duration of the signal, and then it goes high again.
> > with sustain >3, the envelopetriggering behaves normally, but the
> > output is too low compared to the other EGs on the module.
> > additionally, decay and relese also affect the triggering behaviour.
> I had a look at the schematics: this sounds like the wire bridge "J10" 
> has been forgotten or is not solder correctly: it is close to the Decay 
> potentiometer and the IC1 (a 555).
> 
> How does the Envelope react on a slow rectangle LFO at retrigger in 
> while the gate is high (key pressed).
> 
> Florian
>

Hi helitr0n


> one of the four EGs is not working properly:
> when the sustain = 0, the output is high, without beeing triggered.
> however, when a trigger/gate is applied, the envelope stops for the
> duration of the signal, and then it goes high again.
> with sustain >3, the envelopetriggering behaves normally, but the
> output is too low compared to the other EGs on the module.
> additionally, decay and relese also affect the triggering behaviour.
I had a look at the schematics: this sounds like the wire bridge "J10" 
has been forgotten or is not solder correctly: it is close to the Decay 
potentiometer and the IC1 (a 555).

How does the Envelope react on a slow rectangle LFO at retrigger in 
while the gate is high (key pressed).

Florian

just an idea...
i had one malfunctioning adsr, in one of my a143-2,
for a few minutes, until i found out that the tip of
the minijack plug (when it was plugged in of
course)was touching the pins of the led that is right
behind the respective 'adsr out' minijack socket, of
the said adsr. i just bended the pins a bit and
everything was fine!


--- helitr0n <helitron@gmx.net> wrote:

> Hi Florian,
> 
> thanks for the hint. you mean JP5? that looks
> properly soldered, like
> all other solderjoints on the board.
> and retriggering via LFO while holding down the
> gate, does retrigger.
> however it depends on the sustain/decay pot
> settings. if both are low
> the EG goes low when the retrigger signal goes high.
> if decay/sustain
> are high (>3) then it retriggers.
> however the overal env voltage seems low since the
> LED is quite dimm.
> 
> hel
> 
> --- In Doepfer_a100@yahoogroups.com, Florian
> Anwander
> <Florian.Anwander@...> wrote:
> >
> > Hi helitr0n
> > 
> > 
> > > one of the four EGs is not working properly:
> > > when the sustain = 0, the output is high,
> without beeing triggered.
> > > however, when a trigger/gate is applied, the
> envelope stops for the
> > > duration of the signal, and then it goes high
> again.
> > > with sustain >3, the envelopetriggering behaves
> normally, but the
> > > output is too low compared to the other EGs on
> the module.
> > > additionally, decay and relese also affect the
> triggering behaviour.
> > I had a look at the schematics: this sounds like
> the wire bridge "J10" 
> > has been forgotten or is not solder correctly: it
> is close to the Decay 
> > potentiometer and the IC1 (a 555).
> > 
> > How does the Envelope react on a slow rectangle
> LFO at retrigger in 
> > while the gate is high (key pressed).
> > 
> > Florian
> >
> 
> 
>

Hi helitr0n


> thanks for the hint. you mean JP5? that looks properly soldered, 

No I meant J1 (not JP1).

I uploaded the PCB and a cutout from the schematics:
http://launch.ph.groups.yahoo.com/group/Doepfer_a100/photos/browse/935e?c=
It is marked red.


Florian

Hi Florian,

I also tested the J1, it seems ok. like i said everything is soldered
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.

thanks.

--- In Doepfer_a100@yahoogroups.com, Florian Anwander
<Florian.Anwander@...> wrote:
>
> Hi helitr0n
> 
> 
> > thanks for the hint. you mean JP5? that looks properly soldered, 
> 
> No I meant J1 (not JP1).
> 
> I uploaded the PCB and a cutout from the schematics:
>
http://launch.ph.groups.yahoo.com/group/Doepfer_a100/photos/browse/935e?c=

> It is marked red.
> 
> 
> Florian
>

Hi bakis,

no, thats not the problem. it also behaves like that when nothing is
pluged in.
thanks for the hint.
helitron


--- In Doepfer_a100@yahoogroups.com, Bakis Sirros
<synth_freak_2000@...> wrote:

>
> just an idea...
> i had one malfunctioning adsr, in one of my a143-2,
> for a few minutes, until i found out that the tip of
> the minijack plug (when it was plugged in of
> course)was touching the pins of the led that is right
> behind the respective 'adsr out' minijack socket, of
> the said adsr. i just bended the pins a bit and
> everything was fine!
> 
> 
> --- helitr0n <helitron@...> wrote:
> 
> > Hi Florian,
> > 
> > thanks for the hint. you mean JP5? that looks
> > properly soldered, like
> > all other solderjoints on the board.
> > and retriggering via LFO while holding down the
> > gate, does retrigger.
> > however it depends on the sustain/decay pot
> > settings. if both are low
> > the EG goes low when the retrigger signal goes high.
> > if decay/sustain
> > are high (>3) then it retriggers.
> > however the overal env voltage seems low since the
> > LED is quite dimm.
> > 
> > hel
> > 
> > --- In Doepfer_a100@yahoogroups.com, Florian
> > Anwander
> > <Florian.Anwander@> wrote:
> > >
> > > Hi helitr0n
> > > 
> > > 
> > > > one of the four EGs is not working properly:
> > > > when the sustain = 0, the output is high,
> > without beeing triggered.
> > > > however, when a trigger/gate is applied, the
> > envelope stops for the
> > > > duration of the signal, and then it goes high
> > again.
> > > > with sustain >3, the envelopetriggering behaves
> > normally, but the
> > > > output is too low compared to the other EGs on
> > the module.
> > > > additionally, decay and relese also affect the
> > triggering behaviour.
> > > I had a look at the schematics: this sounds like
> > the wire bridge "J10" 
> > > has been forgotten or is not solder correctly: it
> > is close to the Decay 
> > > potentiometer and the IC1 (a 555).
> > > 
> > > How does the Envelope react on a slow rectangle
> > LFO at retrigger in 
> > > while the gate is high (key pressed).
> > > 
> > > Florian
> > >
> > 
> > 
> >
>

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

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
>

Tim

I'll send you private mail, which might help more.

Florian

Hi Florian,

I did as Tim suggested. i took the ICs from the faulty env and put
them into a working one. No change, ist was still working properly.

cheers, hel

--- In Doepfer_a100@yahoogroups.com, Florian Anwander
<Florian.Anwander@...> wrote:

>
> Hi helitr0n
> 
> > both chips, 555 and TL084 are working properly. 
> How did you check this?
> 
> Florian
>

Hi helitr0n

> both chips, 555 and TL084 are working properly. 
How did you check this?

Florian