From yahoo Sent Wed, Feb 20th 2019, 09:29
From yahoo Sent Wed, Feb 20th 2019, 09:29
As already mentioned in the other email the A-126 is a very complex circuit. But if the up shift is working there is some chance that only the adder for the down shifting is faulty. It's built around the TL084 between the two ring modulators MC1496. If replacing the TL084 does not help one has to track the circuit with an oscilloscope to find out what's wrong. Maybe the trimming potentiometer for the down adjustment is broken. Best wishes Dieter Doepfer > -----Ursprüngliche Nachricht----- > Von: xxxxxxx_xxxx@xxxxxxxxxxx.xxx [mailto:xxxxxxx_xxxx@xxxxxxxxxxx.xxx] > Gesendet: Mittwoch, 20. Februar 2019 01:29 > An: xxxxxxx_xxxx@xxxxxxxxxxx.xxx > Betreff: [Doepfer_a100] A-126 Malfunction > > > Hello to you all, > > [What a coincidence with Rigo's broken A-126!]. > > Today I started to try to fix my old A-126 by just replace some > suspected components. > Because the Shift and Mix and Up-Down outputs do not work > properly at all; for you just hear some changes in sound, when > turning the knobs. I mean you do not hear up and down sounds at > the same time. And it also does not go/sound from down to up and > vice versa. > And you do not hear any mix sounds at the Mix output. > And the Up and Down outputs sound the same. > > I started to replace IC 5 (TL064). > And now you can hear the sound goes from down to up (up-shifting > part), but no down-shifting sound to hear. > And the Up and Down outputs still sound the same. > > And now I do not know which components I should replace next. > Is there somebody who please can give me a hint, for I do can > solder very well, so I won't dissapoint you. > > Benny ------------------------------------ ------------------------------------ ------------------------------------ Yahoo Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Doepfer_a100/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Doepfer_a100/join (Yahoo! ID required) <*> To change settings via email: xxxxxxx_xxxx-xxxxxx@xxxxxxxxxxx.xxx xxxxxxx_xxxx-xxxxxxxxxxxx@xxxxxxxxxxx.xxx <*> To unsubscribe from this group, send an email to: xxxxxxx_xxxx-xxxxxxxxxxx@xxxxxxxxxxx.xxx <*> Your use of Yahoo Groups is subject to: https://info.yahoo.com/legal/us/yahoo/utos/terms/