BSS Audio FCS-960 Owner's Manual - Manual (Page 18)

1 8
FCS-930/960
Appendix
Chassis 0V Removal
Transient Suppressor Replacement
8.0 Appendix
for conventional gyrator designs indicate inadequate selectivity at low
levels of boost whilst displaying nearly twice as much combining ripple
at full boost. The adjacent band interaction effect is clearly much more
pronounced, than is evident for the FCS-930/960, as each successive
fader is adjusted.
The FCS-930/960 has the signal 0v ground connected to the metal
chassis, which in turn is connected to the safety ground. In the unlikely
event that you need to remove this link, or if you need to add a small
impedance to reduce earth loop currents, then proceed as follows.
Since both the audio inputs and outputs are wired fully balanced we
would suggest that you fully recheck all audio wiring for correctness,
prior to proceeding.
Under no circumstances should the incoming safety ground wire be
disconnected from the power line cord, or from the internal chassis
connection as an alternative to this procedure.
1 Disconnect the mains power cord and remove the unit’s top cover.
2 Locate the link on the printed circuit board adjacent to the rear PCB
fixing bracket marked ‘GROUND LIFT’.
3 Remove this link.
The signal/0v ground is now isolated from the chassis.
The other link, marked ‘PIN 1 TO CHASSIS’ is connecting the output
XLR pin 1 connections to chassis. Under no circumstances is it
recommended that you remove this link.
The primary of the mains input transformer is protected from high
voltage spike interference by two voltage dependent resistors (VDR).
These provide a momentary short circuit to voltage peaks in excess of
the normal voltage rating.
Should your unit be inadvertently connected to three phase line/line
voltages, or to 240v when selected for 120v, or any other incorrect
voltage, these suppressors are likely to fail in a short circuit mode. This
will be demonstrated by repeated mains fuse failure at switch on.
Even in this case of extreme over voltage the unit is protected against
failure, and the simple removal of these suppressors will allow the unit to
be used again. However it is important that they are replaced as soon as
possible to ensure continued protection.
8.1 Chassis/0v
Removal
8.2 Transient
Suppressor
Replacement