From yahoo Sent Wed, Jul 27th 2016, 07:50
From yahoo Sent Wed, Jul 27th 2016, 07:50
Hello Jacco, all A-143-4 should have a similar frequency range. Maybe the frequency offsets were not adjusted as prescribed. There are four trimming potentiometers on the A-143-4 pc board which are labelled "OFFSET 1" ... "OFFSET 4". These are used to define the frequency offsets. You may try to adjust the trimming potentiometers of the second module so that they match to the other module. Another reason could be a faulty heater. One of the integrated circuits is equipped with a piggyback heater which warms up the circuit at about 40 degrees Celsius. If the heater is defective this may also cause a different frequency range (and even the scale is probably off). Simply compare the temperature of the heaters of the two modules about 10 minutes after power on by means of touching them with the finger. Pay also attention that the jumpers for the bus CV are the same for both modules. Otherwise one of the modules may pick up a CV from the bus which may cause different frequencies. Hope this helps Dieter Doepfer > -----Ursprüngliche Nachricht----- > Von: xxxxxxx_xxxx@xxxxxxxxxxx.xxx [mailto:xxxxxxx_xxxx@xxxxxxxxxxx.xxx] > Gesendet: Dienstag, 26. Juli 2016 23:11 > An: xxxxxxx_xxxx@xxxxxxxxxxx.xxx > Betreff: [Doepfer_a100] Faulty A143-4 vclfo/vco? > > > Hello Dieter, > > While building my new drone station I discovered something odd. > With all new bought modules there is one which doesn't work > properly, an A143-4. > Now I already own two of them so I compared them with the same > (factory) settings, al jumpers in place except for the busCV > jumper which I took out. > With all pots ccw and in LFO mode I slowly turn up the frequency > on channel 1. > There is a big difference between the two modules, one will fully > CW in a rather high speed, the other (faulty?) is probably only > half that speed. > In VCO modus this is about the same, the good module goes really > high (as it should) the other one stays at medium frequency. > The only way to get a really high frequency is by putting the > common pot cw. > I tried al channels and checked all jumpers but I don't know what > this problem is. > Please help. > > Best regards > > Jacco Ville > The Netherlands > > ------------------------------------ > Posted by: xxxxxxxxxx@xxxxx.xxx > ------------------------------------ > > > ------------------------------------ > > Yahoo Groups Links > > > ------------------------------------ ------------------------------------ ------------------------------------ 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/