Watkins-Johnson Company WJ-8718A/MFP Instruction Supplement page 116

WJ-8718A/MFP
TABLE 4-4
4.1.1.2 Receiver BITE Tests
The Receiver BITE Tests are seven tests that .examine (in ord.er) RAM, +15 V,
-15 V, 1st LO, 2nd La, Bandwidth Selection, and BFO Tuning, producing an error code in the
process. Table 4-4 lists these seven tests along with their error codes.
Table 4-4. Receiver BITE Tests
Number Test Error Code
1 RAM
0001
2 +15
V
0002
3 -15
V
0004
4 1st LO 0008
5 2nd LO
0016
6 Bandwidth Selection
0032
7
BFa Tuning 0064
The test in progress is displayed by number in the BFa OFS/THRS LVL display
window. The error code is a binary-weighted code. Any detected errors are summed and
displayed in the FREQUENCY/MHz display window at the end of the seventh test. (A blank
FREQUENCY/MHz display indicates no errors.) If an error is detected, the program should be
cleared and run again to confirm this error. A displayed error does not necessarily indicate that
the receiver is defective.
(It
may be an indication of a loose board, for instance.) Therefore,
the error code should be used solely as a troubleshooting starting point for the maintenance
technician. .
4.1.1.2.1 Access To Receiver BITE Tests
1. Energize the receiver under test and press the front panel LOCAL
key.
2. Press three general purpose keypad buttons: 1,
8,
and
*
(sp,ecial
function).
3. The tests run continually in order, and the test in progr.ess. is
displayed by number (see Table 4-4) in the BFO OFS/THRS LVL
display window.
4. Any detected errors (binary-weighted code) are summed and
displayed in the FREQUENCY/MHz display window at the end of the
seventh test.
5. If an error is detected, the program should be cl.eared and run again
to verify this error.
6. To take the receiver out of the Receiv.er BITE Test mode (and restore
normal operation), press the CLEAR key.
4-5