Doepfer

I have tried with external signal in for the offending pot, but to no avail. Still nothing happens. Its value is still zero, no matter what I send as external signal. 

As far as I remember I tried tracing all connections with the multimeter, comparing to the working row of pots, but could not find any difference. But I will check once more and see what might turn up. 

/Janne

To: Doepfer_a100@yahoogroups.com
From: richyho@virginmedia.com
Date: Fri, 24 Aug 2012 14:11:22 +0100
Subject: [Doepfer_a100] Re: Troubleshooting A-155
















 



  


    
      
      
      Hi



It could be a problem with the jack socket below the pot instead of the pot

itself. I believe that when a lead is plugged into this the knob becomes an

attenuator of this signal. If the socket 'thinks' a cable is plugged in

then that knob may be attenuating zero volts so not doing anything. This

can happen when the metal contacts in the socket become damaged and touch

even when nothing is plugged in. You need to check continuity with a

multimeter, comparing the results with another working socket. Quite a

simple fix with a small screwdriver if this is the case.



Rich



Hi everyone!



I have got an A-155 sequencer where one of the pots on the bottom row does

not work. At all.



In order to try to pin down the error I have swapped the ICs from the top

row to the bottom row (http://www.doepfer.de/A100_pictures/doepfer_a155.jpg,

the two PCBs with the knobs), but the problem was still there. Is there

anything else I can do? I have also tried to measure resistance what is

happening when turning the pot, but I did not see anything that made the

offending pot differ from working pots.



Is the pot itself broken, or is there anything else I should try to pin

down the problem?



Modular regards,



Janne



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