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Farfisa / Acetone Rhythm maker repair.
Farfisa Rhythm Maker Repair – No output. These units are very old. The internal circuitry is similar to an Acetone FR-2L.
The main diode logic and sound generator boards are almost identical but there are differences. The main one being the output pre-amp board and power supply.
The power supply in the Farfisa is just about the most basic one could get using just a bridge rectifier and 500uF capacitor.
Every single electrolytic in this unit tested out of spec. A few were almost twice their rated spec with some reaching as high as four times. There were lots of ‘blobby’ cold solder joints, the latch switches were hard to push as well.
There are meant to be two outputs. A high and a low. Without readable circuit diagrams to confirm it seemed that the only difference in the outputs was a capacitor between signal and ground. Other than that both sockets were hard wired together with the high output using a switched jack socket to ‘disconnect’ the capacitor when in use but the low output has is permanently engaged during use. This just served to muffle the high frequency content.
After receiving some new parts, grease and TLC she is all good to go again.
