Shure U4D Service Manual page 28

FM Detector Quadrature Coil Alignment (Channel B)
ANTENNA A IN
S201
(OFF)
P203
J302
AUDIO ANALYZER
Figure 11. Channel B FM Detector Quadrature Coil Alignment
Service Procedures
Shure U4D Dual Diversity UHF Receiver
RF SIGNAL GENERATOR
P202
P202
TP308
U310
L304 for PCB 34A8507
FL313
for PCB
34A8703
1. Set the rf signal generator Level to –86 dBm and the Deviation
as follows. If necessary, readjust the amplitude so HI EXT and
LO EXT lights turn off.
UA, UB,MA, MB, MC, MD: 45 kHz deviation at 1 kHz modulation
2. Connect the rf signal generator to the ANTENNA B input.
3. Connect the audio analyzer to U310, pin 7 (TP308).
4. For PCB version 34A8507 tune L304 for maximum audio output
at TP308.For PCB version 34A8703 tune FL313 for maximum
audio output at TP308. The low limit is 250 mVrms. There is no
high limit.
27
DC BLOCK
ANTENNA B IN
S201
(OFF)
P202
P202
P203
NOTE: DC VOLTAGES ARE PRESENT
AT MOST RF TEST POINTS. USE A DC
BLOCK ON THE RF SIGNAL GENERATOR
TO PROTECT TEST EQUIPMENT.
KK: 40 kHz deviation at 1 kHz modulation
II: 28 kHz deviation at 1 kHz modulation
25D1062 (AG)