Almost all of the AO-28 pre-amps used in Hammond A-100, B-3, C-3, D-100 and RT-3 organs left the factory without the benefit of fuse protection. In fact, most technicians are quite surprised to learn that during the waning years of production, Hammond did in fact install fuses in a limited number of these pre-amps. Evidence suggests that this was done to pass the more stringent CSA requirements so that it would be possible to export these organs into Canada.
Instead of installing a single fuse on the primary of the pre-amp power transformer, Hammond determined that a fuse on each of the secondary windings offered a higher level of protection. The Trek II ® FPK-28 kit has 4 fuses of the same rating as the ones originally installed by the Hammond factory. By utilizing existing holes in the chassis, the FPK-28 allows these fuses to be easily added to existing AO-28 pre-amps without any drilling or modification to the chassis.
MINIMIZE THE POSSIBILITY OF CATASTROPHIC POWER TRANSFORMER LOSS DUE TO:
- Shorted rectifier tubes
- Shorted filter capacitors
- Shorts in filament / pilot light wiring