Harris Platinum HT EL 2000LS, Техническое руководство

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Often, this will give an indication of whether the problem lies
within the system or the module.
If this does not locate the problem, then the next step is to check
for correct threshold voltages on the module logic board. Fault
blink codes result from a sample voltage taken within the module
exceeding some preset threshold. Thus, if no other module or
system problem is found, the problem may be due to an incor-
rectly set fault threshold (as in the case of thresholds set with
potentiometers), or a defective component (such as a resistor)
used to establish a threshold. Section A.2.8, on the theory of
operation of the module Protection, Control and Monitor subsys-
tem, gives detailed descriptions of how these thresholds are
derived and compared against the corresponding voltage sam-
ples.
Finally, if neither of these steps yields success, the problem may
lie in a PAL or logic gate on the module control board. This type
of problem is generally rare. Measuring voltages at various
points in the logic circuitry on the module control board can
isolate this type of problem.
A set of troubleshooting procedures, one procedure for each fault
code, is given below:
High Output VSWR Fault (1 blink) — The cause for this fault
is often external to the module. First, check the system VSWR
on the display panel, and check for a VSWR foldback or VSWR
overload condition on the transmitter. Check the other modules
in the same cabinet for VSWR faults as well. If either is found,
suspect a problem in the system outside the cabinets.
If not, then the problem is either in the suspect module or its
cabinet. The swap test is the easiest way to isolate the problem.
Swap the VSWR faulting module with a properly working one
from another slot. If the problem remains in the same slot, check
the RF output cable, connector, and combiner reject load for that
module slot.
If the problem follows the module, check the solder connections
at the directional coupler and the RF output jack inside the
module. If no problem is found, the problem could be an improp-
erly set VSWR fault threshold or a defective module logic board.
See paragraphs giving procedure used to check and set the
VSWR threshold located on page A-18.
Input Overdrive Fault (2 blinks) — Normally, this protects the
module from damage due to excess RF drive (at least 3 dB above
the drive required to drive the module to full power). To isolate
the cause of fault, reduce the visual exciter RF output to zero,
Figure A-5. Module Test Fixture
Platinum™ Series
A-8 888-2457-001
WARNING: Disconnect primary power prior to servcing.