Doepfer

Hello,

one of my three A147 has stopped working, well, the leds still light up but not moving 
anymore or so so so so slowly...

I've had this module for about 6 or 8 years... I remember in fact that it happens to me 
once already this problem, and after a while I re-install the module and it worked again 
OK. this time it seems to not want to rework, plus I am not sure if it is the same A147 (but 
somehow I guess so).

any idea? what should can I do?


Best regards,


Alexandre

Hi Alexandre,

> any idea? what should can I do?

Well if the CA3080 chip is socketted on yours, as it is on mine, check 
that it is properly seated in the socket by pushing down on it. ICs can 
slowly work out of their sockets, and a bad connection could easily 
cause the type of behaviour you are seeing.

Tim

thanks Tim, I'll try this out and report back,


best


a

> Well if the CA3080 chip is socketted on yours, as it is on mine, check 
> that it is properly seated in the socket by pushing down on it. ICs can 
> slowly work out of their sockets, and a bad connection could easily 
> cause the type of behaviour you are seeing.
> 
> Tim
>

Well I checked the CA3080... but it didnt change anything

in fact, it seems nearly to not move at all anymore...

when I plug the case on it changes position once and then seems to never progress 
anymore....


I checked my two others A147... there are similar but the one not working has got slighlty 
different components... I am not sure but probably the one not working is the oldest one


should I try to replace the CA3080 of the not working module with one of the CA3080 
from one of the other A147...

or whatelse can I do?

Dieter, any idea?


Best,


Alexandre



--- In Doepfer_a100@yahoogroups.com, "bellenger_a" <bellenger_a@...> wrote:

>
> thanks Tim, I'll try this out and report back,
> 
> 
> best
> 
> 
> a
> 
> 
> > Well if the CA3080 chip is socketted on yours, as it is on mine, check 
> > that it is properly seated in the socket by pushing down on it. ICs can 
> > slowly work out of their sockets, and a bad connection could easily 
> > cause the type of behaviour you are seeing.
> > 
> > Tim
> >
>

> -----Ursprüngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com
> [mailto:Doepfer_a100@yahoogroups.com]Im Auftrag von bellenger_a
> Gesendet: Montag, 11. August 2008 13:23
> An: Doepfer_a100@yahoogroups.com
> Betreff: [Doepfer_a100] Re: A147 not working anymore
>
>
> Well I checked the CA3080... but it didnt change anything
>
> in fact, it seems nearly to not move at all anymore...
>
> when I plug the case on it changes position once and then seems
> to never progress
> anymore....
>
>
> I checked my two others A147... there are similar but the one not
> working has got slighlty
> different components... I am not sure but probably the one not
> working is the oldest one
>
>
> should I try to replace the CA3080 of the not working module with
> one of the CA3080
> from one of the other A147...
>
> or whatelse can I do?
>
> Dieter, any idea?
>
>
> Best,
>
>
> Alexandre

I'd recommend to move one integrated circuit after the other from a working
module to the not working one. Thus you can find out if one of the circuits
is defective or not. If it does not help the module has to be sent in for
repair. Please look also if there are mechanical faults (e.g. broken part or
pc board). But this can happen normally only if the module has been moved or
transported outside the frame.

Best wishes
Dieter Doepfer

> I'd recommend to move one integrated circuit after the other from a working
> module to the not working one. 

well I tried that, replaced the CA3080 from a working A147.. still not working... and for 
the other circuits its not possible. The two others A147 I have are different versions than 
the one not working, the components are directly soldered on the pc board...

so... i'm affraid I have to send this modulein for repair...

I checked all other components and nothing seems unsoldered or missing....


Best,



Alexandre

> The modules with the directly soldered circuits are probably older ones

OK


> Only the upper of the two remaining integrated circuits (IC2/TL084) is
> required for basic operation. The lower circuit (IC3/TL064) is used only to
> generate the waveforms sine and sawtooth. It can be removed for testing
> (sine and saw will then not work). The TL084 (quad OpAmp) is used in many
> A-100 modules. Maybe you have a module at hand from which you can borrow the
> TL084

OK... I will try this...


any idea which module???


and also... I have to add that the module somehow still works... the outputs works... but 
when I send a cv in the cv in it seems to not change anything...


Thanks for quick answer as always Dieter,


Best regards,


A
lexandre

> well I tried that, replaced the CA3080 from a working A147..
> still not working... and for
> the other circuits its not possible. The two others A147 I have
> are different versions than
> the one not working, the components are directly soldered on the
> pc board...
>
> so... i'm affraid I have to send this modulein for repair...
>
> I checked all other components and nothing seems unsoldered or missing....
>
> Best,
> Alexandre

The modules with the directly soldered circuits are probably older ones
(manufactured before ~ 2000) as we use sockets for all circuits since many
years for easier service.

Only the upper of the two remaining integrated circuits (IC2/TL084) is
required for basic operation. The lower circuit (IC3/TL064) is used only to
generate the waveforms sine and sawtooth. It can be removed for testing
(sine and saw will then not work). The TL084 (quad OpAmp) is used in many
A-100 modules. Maybe you have a module at hand from which you can borrow the
TL084.

If even this will not help the module has to be sent in for repair.

Best wishes
Dieter Doepfer

> and also... I have to add that the module somehow still works...
> the outputs works... but when I send a cv in the cv in it seems to not
change anything...

Are you able to change the frequency with the manual frequency control ?

If yes -> probably the CV input socket or the attenuator potentiometer is
defective or broken
If no  -> probably the exponential current source around the two transistors
Q1/Q2 (both BC559) and the TL084 has a fault

You may even try the lower TL064 instead of the TL084. For the final module
the upper should be an TL084 again but for testing you may use also the
TL064 instead of the TL084.

Good luck
Dieter Doepfer

> Are you able to change the frequency with the manual frequency control ?

NO



> You may even try the lower TL064 instead of the TL084. For the final module
> the upper should be an TL084 again but for testing you may use also the
> TL064 instead of the TL084.

changed all the components from another module and still not working...


I have to send it to you then....


Best regards,


Alexandre