Modification to SF 1000 – 1 kW Solid State Amplifier

We have noticed a problem with an early failure of the fuse located on the Control Board of the 2 kW Power Supply module of our SF-1000. (SF3047 Board)

In order to avoid nuisance failures of this fuse, we recommend that you make the following simple modifications:

1) Soldier in parallel to R80 a 47nf, 50V ceramic capacitor.

2) Connect the lead closest to U15 of R86 to the side of C54 connected to ground in order to connect R86 to ground.

Download and print out a schematic pictorial showing the locations of the modifications here.