A method of changing the source of the zone power from 100 volt to 70volt
The Yorkville CA1 commercial install amp has both 70 and 100volt capability. When a
customer wishes to convert the zone output from 100 volts down to 70 volts, he may follow
these easy steps to modify the supply board which is the middle of the three barrier strips
on the rear of the unit.
1) remove the main chassis cover
2) while facing the rear of the unit, remove all 3 of the speaker terminal strips
3) the top and bottom strips will come out easily but you will probably have to unsolder
and remove the yellow varistor from the middle terminal strip. This is a little tricky
because you will have to unscrew the middle strip and flip the amp over to gain access
to the solder on the varistor.
4) Once the middle strip is free of the chassis all you have to do is cut one trace and add
one jumper as shown in the following before and after photos.
5) After you have made the mod to the board , re-install all the strips and the cover.
6) The first photo shows the trace side of the middle barrier board without the cut and
jumper added.
7) The second photo shows the same board with the trace cut above the last pin on the
right and a jumper added between the last pin and the fourth from the last pin.
8) That is it except for re-assembly.
CUT HERE
