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XR = J1500C
5. ADJUSTMENTS
5.1 CLOCK FREQUENCY ADJUSTMENT
(1) Connect a Frequency Counter to TP! and G on the
FRONT PCB ASSY via the BUFFER AMP PCB as
shown in Fig. 1.
(2) Adjust TC90! so that the frequency becomes
4.194304MHz
+ 40Hz (4.194264MHz to 4.194344
MHz).
FRONT PCB ASSY
TO
aesvyt*é«~i
Frequency counter
1s:
S
B
1M
10k
Phe ea fos es on
BUFFER AMP PCB
Fig. 1 Clock Frequency Adjustment
5.2 TUNER SECTION
5.2.1 FM TUNER SECTION
li FM Range Adjustment
(1) Connect FM RF signal generator input through JK101
FM antenna IN.
(2) Digital DC voltmeter connected to TP2 on the TUNER
PCB ASSY.
(3) Tuning
to 87.5MHz,
adjust
L103
and
let counter
reading as 1.2V + 0.05V.
(4) Tuning to 1O8MHz, check the reading as 6.5V to 8.5V.
(5) Repeat adjustments as necessary to minimize tracking
error.
FM
Sensitivity Adjustment
(1) Connect FM RF signal generator input though JK101
FM antenna IN.
(2) Oscilloscope connected to speaker terminal. (pin 3 and
4 of JK501)
(3) Tuning to 9OMHz, adjust L102 for maximum output.
(4) Tuning to 1O6MHz, adjust TC101 for maximum output.
(5) Repeat adjustments as necessary to L102 and TC101
for maximum output.
42
5.2.2 AM TUNER SECTION
i AM Range Adjustment
(1) AM RF signal generator output from loop antenna, and
received by AM loop antenna.
(2) Digital DC voltmeter connected to TP2 on the TUNER
PCB ASSY.
(3) Tuning to 530kHz, adjust L105 and let counter reading
as 1.1V + 0.0SV.
(4) Tuning to 1720kHz, check counter reading as 6.5V to
8.5V.
(5) Repeat adjustments as necessary to minimize tracking
error.
AM Frequency : 530kHz to 1720kHz (10kHz Step)
5§22kHz to 1611kHz (9kHz Step)
@ AM IF Adjustment
(1) Connect AM
SG (999kHz
mod.
30%; 400Hz;
63dB)
input from JK101 AM antenna terminal IN.
(2) Connect the oscilloscope to TP] on the TUNER
PCB
ASSY.
(3) Adjust T102 on the TUNER PCB ASSY for maximum
output. (Fig. 2)
450kHz
Fig. 2
AM
Sensitivity Adjustment
(1) Tuning to 600kHz, adjust L104 on the TUNER
PCB
ASSY for maximum output. (Fig. 3)
(2) Tuning
to
1400kHz,
adjust TC102
for maximum
output. (Fig. 3)
(3) Repeat adjustments as necessary to L104 and TC102
for maximum output.
{Vp-p to MAX.)
Vp-p
Fig. 3
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