Ps Controller Faults; Life Support Board; Normal Operational Mode - Harris Platinum Z2 CD Manual

Overall System Theory

4.7.5.8 PS Controller Faults

For a complete listing of all of the faults associated with the PS Controller refer to
Section VI, Troubleshooting.
4.7.6
The Master Controller is backed up by the Life Support Board. The Life Support
Board allows safe transmitter operation at reduced power if the Master Controller is
not operating. The transmitter does require the PA and PS Controller(s) to be
operational. The basic controller functions available in Life Support Mode are:
The Life Support Board has two basic modes of operation:
1. Normal Operational Mode. The Life Support Board basically acts as an interface
between the Master Controller and various parts in the transmitter when the Master
Controller is functioning properly. 2. Life Support Mode. This mode provides a
minimal backup control system should the Master Controller fail. If the Master
Controller board fails, the Life Support Board disconnects (via AND gates) all
signals from the Master Controller and allows the transmitter to stay on the air at 1/
4 power with minimal fault protection and no visible monitoring for the operator.
Transmitter functions available in Life Support Mode:
a. VSWR Protection
b. System Mute
c. Transmitter ON (LOW only) and OFF (both LOCAL and REMOTE inputs
are active)
d. Failsafe Interlock
e. External Interlock

4.7.6.1 Normal Operational Mode

The following contains all pertinent circuit operation when the Master Controller is
functioning properly.
4.7.6.1.1 Transmitter Turn On
When the transmitter is turned on, either HIGH or LOW, the Master Controller
generates a high TX_ON signal which enters the Life Support Board at J1-A55 and
is tied to AND gate U26-9. TX_ON is generated when either LOW ON or HIGH
ON is pressed on the front panel, or when a remote HIGH ON is sent from the
remote control system. Since the Master Controller is working, U26-10 is high
which sends a high via U26-8 to OR gate U32-10. This brings U32-8, U32-11 and
finally U4-12 high.
WARNING: Disconnect primary power prior to servicing.

Life Support Board

888-2406-002 4-47