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: Doepfer_a100@yahoogroups.com [mailto: Doepfer_a100@yahoogroups.com ]
> Gesendet: Dienstag, 26. Juli 2016 23:11
> An: Doepfer_a100@yahoogroups.com
> Betreff: 1 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: jaccoville@...
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