Doepfer

Symptoms: DNG RND CLC outputs a thin oscillator sound without the digital noise present. other outputs are fine.

It sounds to me as if there is an oscillator that drives the digital sound source and only the driver is functioning.

In this picture:
http://3.bp.blogspot.com/_d9uh_FFQZoQ/SW_321zu3zI/AAAAAAAAAFM/vAu-C9ki aw4/s1600-h/a117m.jpg

If I make this simple connection the unit sounds good when something is patched into the ext. Clk input AND can be tuned.

I spotted following chips:
cd40106b
cd4006
cd4070

Please let me know what the others 2 are and if these are correct.


Thank you.

+++++++++++++++++++++++++

I thought I posted this yesterday but it didn't appear in the archive. My apologizes if anyone receives this twice.

Hi Tommy,

> I spotted following chips:
> cd40106b
> cd4006
> cd4070
> 
> Please let me know what the others 2 are and if these are correct.

There are *two* 40106, and the 8-pin chip is a dual op amp (TLC272 in mine).

> It sounds to me as if there is an oscillator that drives the digital sound source and only the driver is functioning.

Correct. The 40106 at the bottom of the board acts as 6 oscillators for the '808 source'; the other one (topmost on the board, opposite the pot), is the tunable oscillator that clocks the 4006 shift register, which is what generates the digital noise.

If it is running OK from the ext clock, then it sounds like that top 40106 might be blown - you could easily swap it with the other to see what happens (indeed, checking that all the ICs are firmly pressed into their sockets would be a good thing to do).

> In this picture:
> http://3.bp.blogspot.com/_d9uh_FFQZoQ/SW_321zu3zI/AAAAAAAAAFM/vAu-C9ki aw4/s1600-h/a117m.jpg
> 
> If I make this simple connection the unit sounds good when something is patched into the ext. Clk input AND can be tuned.

Sorry, I don't quite follow that - is that both ends of the same wire? If so, it is hard-wiring the internal osc to the 4006 clock input (i.e. just bypassing the switching contact in the jack socket), in which case the comment about it working when something external is connected doesn't make sense to me, nor it being 'tuned'??!

Tim

Thanks for the response Tim.

> > In this picture:
> > http://3.bp.blogspot.com/_d9uh_FFQZoQ/SW_321zu3zI/AAAAAAAAAFM/vAu-C9ki aw4/s1600-h/a117m.jpg
> > 
> > If I make this simple connection the unit sounds good when something is patched into the ext. Clk input AND can be tuned.
> 
> Sorry, I don't quite follow that - is that both ends of the same wire? If so, it is hard-wiring the internal osc to the 4006 clock input (i.e. just bypassing the switching contact in the jack socket), in which case the comment about it working when something external is connected doesn't make sense to me, nor it being 'tuned'??!
> 

Hopefully I can clarify this last bit.

If I remember correctly from before the unit acted up... the rate knob no longer functions once an external source is used. With the hardwire I did I found that with a external clock source inserted the digital noise returned and was now tunable against the incoming sound.

A better mofd would be to make the lower OSC tunable. 
TD

The internal oscillator is fed via the switching contact of the Ext.CLK
socket. If the switching contact of this socket is worn out is does no
longer make contact. Maybe this is the reason. Try an external oscillator
connected to the Ext.CLK socket to find this out.

Best wishes
Dieter Doepfer

> -----Ursprüngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com
> [mailto:Doepfer_a100@yahoogroups.com]Im Auftrag von Tommy DOG
> Gesendet: Sonntag, 8. März 2009 13:34
> An: Doepfer_a100@yahoogroups.com
> Betreff: [Doepfer_a100] Doepfer A-117 trouble
>
>
> Symptoms: DNG RND CLC outputs a thin oscillator sound without the
> digital noise present. other outputs are fine.
>
> It sounds to me as if there is an oscillator that drives the
> digital sound source and only the driver is functioning.
>
> In this picture:
> http://3.bp.blogspot.com/_d9uh_FFQZoQ/SW_321zu3zI/AAAAAAAAAFM/vAu-
> C9ki aw4/s1600-h/a117m.jpg
>
> If I make this simple connection the unit sounds good when
> something is patched into the ext. Clk input AND can be tuned.
>
> I spotted following chips:
> cd40106b
> cd4006
> cd4070
>
> Please let me know what the others 2 are and if these are correct.
>
>
> Thank you.
>
> +++++++++++++++++++++++++
>
> I thought I posted this yesterday but it didn't appear in the
> archive. My apologizes if anyone receives this twice.
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>

Thanks Dieter.
I already replaced the socket.

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

>
> The internal oscillator is fed via the switching contact of the Ext.CLK
> socket. If the switching contact of this socket is worn out is does no
> longer make contact. Maybe this is the reason. Try an external oscillator
> connected to the Ext.CLK socket to find this out.
> 
> Best wishes
> Dieter Doepfer
> 
> 
> > -----Ursprüngliche Nachricht-----
> > Von: Doepfer_a100@yahoogroups.com
> > [mailto:Doepfer_a100@yahoogroups.com]Im Auftrag von Tommy DOG
> > Gesendet: Sonntag, 8. März 2009 13:34
> > An: Doepfer_a100@yahoogroups.com
> > Betreff: [Doepfer_a100] Doepfer A-117 trouble
> >
> >
> > Symptoms: DNG RND CLC outputs a thin oscillator sound without the
> > digital noise present. other outputs are fine.
> >
> > It sounds to me as if there is an oscillator that drives the
> > digital sound source and only the driver is functioning.
> >
> > In this picture:
> > http://3.bp.blogspot.com/_d9uh_FFQZoQ/SW_321zu3zI/AAAAAAAAAFM/vAu-
> > C9ki aw4/s1600-h/a117m.jpg
> >
> > If I make this simple connection the unit sounds good when
> > something is patched into the ext. Clk input AND can be tuned.
> >
> > I spotted following chips:
> > cd40106b
> > cd4006
> > cd4070
> >
> > Please let me know what the others 2 are and if these are correct.
> >
> >
> > Thank you.
> >
> > +++++++++++++++++++++++++
> >
> > I thought I posted this yesterday but it didn't appear in the
> > archive. My apologizes if anyone receives this twice.
> >
> >
> >
> > ------------------------------------
> >
> > Yahoo! Groups Links
> >
> >
> >
>

Did it solve the problem ?

Dieter

> -----Ursprüngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com
> [mailto:Doepfer_a100@yahoogroups.com]Im Auftrag von Tommy DOG
> Gesendet: Montag, 9. März 2009 13:29
> An: Doepfer_a100@yahoogroups.com
> Betreff: [Doepfer_a100] Re: Doepfer A-117 trouble
>
>
> Thanks Dieter.
> I already replaced the socket.
>
> --- In Doepfer_a100@yahoogroups.com, <yahoo@...> wrote:
> >
> > The internal oscillator is fed via the switching contact of the Ext.CLK
> > socket. If the switching contact of this socket is worn out is does no
> > longer make contact. Maybe this is the reason. Try an external
> oscillator
> > connected to the Ext.CLK socket to find this out.
> >
> > Best wishes
> > Dieter Doepfer