Specifications

the A/D board. This will display an RF MUTE, A/D Supply Fault
and Conversion Error on the Control front panel when the trans-
mitter is turned on.
K.6.4.1 Transmitter goes to maximum power (All RF AMPS
on)
a. Check the A/D input meter on the Transmitter Multimeter
located in the Right PA compartment.
b. Compare this to the normal reading from the Factory test
data or station log.
c. If this is not correct, check for the (Audio + DC) signal at
TP22.
d. If this signal is correct check U1, CR1, CR2, and U14. If
the A/D input is correct:
e. Apply an RF MUTE with S1 on the Controller. The meter
reading should drop to zero.
f. Check the inputs to Latches U6 and U7. They should all
be at logic low.
g. If any of these are high suspect a bad U3.
h. If these are all low check the output pins for a logic low.
i. If any of these are high, replace the Latch (U6 or U7) and
or check U15.
j. If these outputs are low, check U8 and U9 for correct
action.
K.6.4.2 No power output
Begin by observing if Conversion Error DS5 is illuminated on
the A/D Board when the transmitter is turned on.
K.6.4.2.1 DS5 Illuminated
If the conversion fault is present, then while the transmitter is on:
a. Check TP4 for a clock pulse.
b. If this pulse is not present check for the pulses coming from
the Driver Encoder at R12 of this board.
c. If the pulses are not present at R12, refer to the overall
wiring diagram and the Driver Encoder Section to con-
tinue.
d. If the pulses are present check Q1, CR3, U10 and U4.
e. If the clock pulse is present on TP4, check for a series of
Start Encode pulses at TP2 with the transmitter on.
f. If the start encode pulses are not present suspect a bad U5.
g. If the start encode pulses are present on TP2, apply audio
to the transmitter and check the A/D input meter on the
Transmitter Multimeter located in the Right PA compart-
ment.
h. Compare this to normal reading from the Factory test data
or station log.
i. If this is not correct, check for the audio +DC signal at
TP22.
j. If this signal is correct check U1, CR1, CR2, and U14.
k. If the A/D input is correct, replace U5, and if fault remains
replace U3.
K.7 Removal and Replacement
Remove the 10 screws and 4 connectors from the board. Reverse
the procedure for replacement. When replacing the board set S1,
P11 and P10 to the same setting as the removed board.
K.8 Alignments
There are no alignments needed on this board.
K-6 888-2339-002
WARNING: Disconnect primary power prior to servicing.