Table of Contents
Advertisement
4. AFC RESPONSE ALIGNMENT
4.1.
EQUIPMENT
4.1.1.
Sweep/marker generator
4.1.2,
Monitor scope
4.1.3,
DC Power supply (+16.5V)
4.1.4,
Bias supply (t4V~+4.5V)
4.1.5,
Matching Pad
4.1.6.
Direct probe
4.1.7.
Digital Voltmeter
4.2.
PREPARATION
4.2.1.
Apply +16.5 volts to TP—16 on main board.
4.2.2.
Apply +4V
+4.5 volts to TP14 on main board.
4.2.3.
Connect the output of sweep/marker generator through the matching pad to test point of tuner.
4.2.4.
Connect the monitor scope with direct probe to terminal TP-17.
4.2.5,
Put the AFC switch "OFF". (except remote control model)
4.2.6.
Gradually increase or decrease the output of sweep/marker generator to obtain the 2Vp—p
response
curve.
4.5.
STEP
Adjust T172(AFC TANK COIL) the PIF marker position to be kept just the reference level.
After this adjustment, PIF keying pulse on the monitor scope must be in minimum amplitude.
(Refer to Figure 8.)
PIF (P) Point
Minimum
Amplitude
Level
ji
2Vp-p
PAL B/G,SECAM
B/G,D/K
38.9MHz
Keying pulse
Figure 8.
AFC Response Alignment
Advertisement
Table of Contents
