Doepfer

Hi to you all,

Just to follow up to my last post about this issue, it seems like it's only the A-155 that is having grounding issues in the rack. Is this because it gets its grounding via the A-154? Can it have a secondary connector to give it its own ground?

Neil

Sent from my iPhone

> Hi to you all,
>
> Just to follow up to my last post about this issue, it seems like it's only the A-155 that is having grounding issues in
> the rack. Is this because it gets its grounding via the A-154? Can it have a secondary connector to give it its own ground?
>
> Neil

I have never heard about grounding problems of the A-154/A-155 combo and there are more than 1000 of these combos in use. Maybe it's
only a loose connector. I'd try to dis-connect the re-connect all cables between A-154 and A-155.

Best wishes
Dieter Doepfer

Ok I'll try that later thanks.

Neil

Sent from my iPhone

> On 1 May 2015, at 12:24, yahoo@doepfer.de [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:
> 
> > Hi to you all,
> >
> > Just to follow up to my last post about this issue, it seems like it's only the A-155 that is having grounding issues in
> > the rack. Is this because it gets its grounding via the A-154? Can it have a secondary connector to give it its own ground?
> >
> > Neil
> 
> I have never heard about grounding problems of the A-154/A-155 combo and there are more than 1000 of these combos in use. Maybe it's
> only a loose connector. I'd try to dis-connect the re-connect all cables between A-154 and A-155.
> 
> Best wishes
> Dieter Doepfer
> 
>

Just found another user on Muffwiggler who has the same issue: 

 <https://www.muffwiggler.com/forum/viewtopic.php?p=1886065#1886065>Posted: Sat May 02, 2015 9:28 am    Post subject: 	 <https://www.muffwiggler.com/forum/posting.php?mode=quote&p=1886065>  <https://www.muffwiggler.com/forum/ignore.php?mode=add&username=Apfelmann&topic=137589>
had the same Problem, no gates or Triggers as long as i wont send a clock from the a 154 or recieve a clock, never had that Problem before but since i have put it into the lc3 it was there. 

did remove it from the lc3 to put it into my diy case, wich isnt ready yet but ill try as soon as im finished with building the case

Is te LC3 grounded like the other cases are?

Neil

> On 1 May 2015, at 15:01, Neil Kagan blinkenlicht@yahoo.com [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:
> 
> 
> Hi Dieter,
> 
> Ok I have done some more troubleshooting. Once separated again, the A-155 still doesn’t output a trigger in one of the LC3 cases (the ones with he power adaptor) but it does work in the LC 9 and LC base which have a direct mains connector. It also works fine as soon as another socket on the a-155 is plugged into a module in any of the other cases which seems to me a grounding issue but I don’t know why!
> 
> Neil
> 
> 
>> On 1 May 2015, at 12:24, yahoo@doepfer.de <mailto:yahoo@doepfer.de> [Doepfer_a100] <Doepfer_a100@yahoogroups.com <mailto:Doepfer_a100@yahoogroups.com>> wrote:
>> 
>> > Hi to you all,
>> >
>> > Just to follow up to my last post about this issue, it seems like it's only the A-155 that is having grounding issues in
>> > the rack. Is this because it gets its grounding via the A-154? Can it have a secondary connector to give it its own ground?
>> >
>> > Neil
>> 
>> I have never heard about grounding problems of the A-154/A-155 combo and there are more than 1000 of these combos in use. Maybe it's
>> only a loose connector. I'd try to dis-connect the re-connect all cables between A-154 and A-155.
>> 
>> Best wishes
>> Dieter Doepfer
>> 
>> 
> 
> 
>

> Hi Dieter,
>
>
> Ok I have done some more troubleshooting. Once separated again, the A-155 still doesn’t output a trigger in one of the
> LC3 cases (the ones with he power adaptor) but it does work in the LC 9 and LC base which have a direct mains connector.
> It also works fine as soon as another socket on the a-155 is plugged into a module in any of the other cases which seems
> to me a grounding issue but I don’t know why!
>
> Neil

Hello Neil,

I took a look at the technical records (schematics, pcb layout) and there should be no problem (i.e. the sockets of the trigger
outputs should be grounded). But I also took a look at a A-155 module and indeed the four trigger sockets are not connected to GND.
I traced the GND signal and found the error: the 10 pin connector on the long trigger board which is used to connect the small board
has no GND. It's mysterious because our technical records say that the connector is grounded. I suppose that the fault occured a few
years ago when the pcb manufacturer told us that they are not able to manufacture the pcbs from the old documents any longer (the
A-155 was developed nearly 20 years ago on an Atari system). But they mentioned that it's possible to scan the old films so that
they can be used in the future. I suppose that during this procedure the fault happened. During the test of the A-155 the missing
GND of the trigger sockets is not recognized as the modules are tested in combination with other modules in the same frame (i.e.
with the same common GND). The fix is very simple: on has to connect one of the pins of the 10 pin connector of the trigger board to
GND. The GND track is just next to the pin so that a small solder blob solves the problem. I'll prepare a document that show the
position of the required solder connection. I'm quite sure that older A-155 (manufactured directly from the Atari data) do not have
this problem.

Best wishes and sorry for the troubles
Dieter Doepfer

Thanks Dieter, at least I know I'm not going crazy now!

Neil

Sent from my iPhone

On 2 May 2015, at 15:35, yahoo@doepfer.de [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:

>> Hi Dieter,
>> 
>> 
>> Ok I have done some more troubleshooting. Once separated again, the A-155 still doesn’t output a trigger in one of the
>> LC3 cases (the ones with he power adaptor) but it does work in the LC 9 and LC base which have a direct mains connector.
>> It also works fine as soon as another socket on the a-155 is plugged into a module in any of the other cases which seems
>> to me a grounding issue but I don’t know why!
>> 
>> Neil
> 
> Hello Neil,
> 
> I took a look at the technical records (schematics, pcb layout) and there should be no problem (i.e. the sockets of the trigger
> outputs should be grounded). But I also took a look at a A-155 module and indeed the four trigger sockets are not connected to GND.
> I traced the GND signal and found the error: the 10 pin connector on the long trigger board which is used to connect the small board
> has no GND. It's mysterious because our technical records say that the connector is grounded. I suppose that the fault occured a few
> years ago when the pcb manufacturer told us that they are not able to manufacture the pcbs from the old documents any longer (the
> A-155 was developed nearly 20 years ago on an Atari system). But they mentioned that it's possible to scan the old films so that
> they can be used in the future. I suppose that during this procedure the fault happened. During the test of the A-155 the missing
> GND of the trigger sockets is not recognized as the modules are tested in combination with other modules in the same frame (i.e.
> with the same common GND). The fix is very simple: on has to connect one of the pins of the 10 pin connector of the trigger board to
> GND. The GND track is just next to the pin so that a small solder blob solves the problem. I'll prepare a document that show the
> position of the required solder connection. I'm quite sure that older A-155 (manufactured directly from the Atari data) do not have
> this problem.
> 
> Best wishes and sorry for the troubles
> Dieter Doepfer
> 
> 
> 
> ------------------------------------
> 
> ------------------------------------
> 
> 
> ------------------------------------
> 
> Yahoo Groups Links
> 
> 
>

Neil,

I'll send you a pdf document that describes the fix of the missing GND. In addition we will add the document to our website (FAQ and
DIY page).
We will add the fix to all A-155 which are still in stock and from the next production series the pc boards will be corrected.

Best wishes
Dieter Doepfer


> -----Urspr�ngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com [mailto:Doepfer_a100@yahoogroups.com]
> Gesendet: Samstag, 2. Mai 2015 18:10
> An: Doepfer_a100@yahoogroups.com
> Betreff: Re: AW: [Doepfer_a100] A-155 grounding
>
>
> Thanks Dieter, at least I know I'm not going crazy now!
>
> Neil


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