Harris Platinum HT EL 2000LS, Техническое руководство

Страница: 73 / 90

IMPORTANT
These modules operate with 50 Volt power supplies capable of very high
currents. Accidental short circuits occurring inside the modules can cause
serious damage due to the high currents involved. Carefully inspect the
module for any debris that could cause a short to occur after any repair
activity.
IMPORTANT
Failure to use proper soldering techniques or materials can cause damage
to the replacement components, or may result in joints with poor electrical
or mechanical integrity, causing subsequent damage to the module. Please
read the section entitled “Soldering Precautions” before attempting any
repair activity.
A.3.1
Platinum™ TV Module Test Fixture (992-8556-002)
Refer to Figures A-4 & A-5
The Platinum TV Module Test Fixture consists of a table top
assembly with a interconnect cable ending in a plug assembly
that is inserted into an empty module slot. The cable to the test
load is routed through the end cover opposite the fan and con-
nected inside the test fixture by reaching through the cooling slot.
An interlocked Safety Cover must be in place to activate RF drive
to the module under test.
Breaker CB1 limits the current to 50 amps, protecting the cable.
Breaker CB2 at the test fixture trips from excess module current
and can be used as module power switch. Interlock switch S2 and
driver relay K1 prevent application of RF drive until the cover is
closed.
Fuse F1 provides protection for the small signal wiring in the
extender and the 50 Volt DC fan.
Enable switch S1 allows local control of the module on the
extender while the transmitter is on.
CAUTION
AN EXTERNAL RF LOAD MUST BE CONNECTED TO THE MOD-
ULE AT ALL TIMES DURING TEST.
BE SURE TO DISABLE AND REMOVE THE MODULE OR TURN
OFF THE BREAKER BEFORE REMOVING THE EXTENDER FROM
THE CABINET.
A.3.2
Troubleshooting Based on Module Swapping
Many situations exist in which a problem exhibited by a module
could be due to a problem either with the module itself, or
somewhere else in the transmitter. For example, VSWR faults
could be due to either a failure or misadjustment of the VSWR
sensing circuitry in the module, or due to a problem with the
transmitter cabinet RF connector, combiner cables, reject loads,
etc. In fact, most fault indications could be caused by either
module or system problems. Thus it is desirable to first isolate
the problem to the module or system before continuing the
troubleshooting process.
Since the modules are designed for interchangeability with other
modules of the same type, one easy test to determine whether a
problem lies in the system or in the module is the “swap test,”
which involves swapping the suspect module with another and
observing whether the symptom follows the module.
A.3.3
Troubleshooting Based on Module Blink Codes
The general procedure for troubleshooting based on a module
blink code involves several steps.
The first is to check for causes consistent with the blink code
(such as checking the DC supply voltage if blink code 4 occurs).
Figure A-4. Wiring Diagram PA Module Extender
(Harris PN 992-8556-001) (Drawing 843 5285 162)
Appendix A - RF Amplifier Modules
888-2457-001 A-7
WARNING: Disconnect primary power prior to servcing.