AM SECTION
1. FREOUENCV COVERAGE AND TRACKING ADJUSTMENT
The following is intended to described the procedure of adjusting the AM section of the receiver using a sweep
generator.
ln the adjustment, the output voltage is applied through inductive coupling.
For adjustment. place a loop antenna near the receiver under test and ovserve the waveform of detector output
(at the point lf22 on the Tuner PCB Assy Board)displayed on the alignment oscilloscope.
For adjustment point, refer to Fig. 2.
The waveform disprayed on the arigment oscilloscope is as shown in Fig. Fig.3.
Step Generator and Dial Freq. Adjust lndication and Remarks
152O KHz T301 Oscillator coil core adjust for
maximum reading
21650 KHz AM2 Oscillator trimmer adjust for
maximum reading
3600 KHz AM BAR ANT. Antenna coil adjust for
maximum reading
41400 KHz AMl Antenna trimmer adjust for
maximum readinq
5Repeat steps 1-4 to obtain best tracking
2. AM-IF STA.GE ADJUSTMENT
This adjustment is similar to the frequency coverage and tracking adjustment. Switch the sweep generator from RF
to lF and follow the procedure below.
The adjusting procedure is as follows:
(1) With the receiver set to a high receiving frequency (variable capacitor in full open position), adjust T302 and
T303 until the lF waveforem becomes maximum.
(21 lf , in this case, the adjustment is difficult because of disturbing sighal,
facilitate the adjustment.
(3) The waveform displayed on the aligment oscilloscope is as shown in Fig. 4. For adjusting posint, refer to Fig. 2.
the variable capacitor may be turned to
520KHZ
MARKER SIGNAL 1,650KH2
MARKER
SIGNAL
600KHZ 1400KHZ
MABKER MARKER
SIGNAL SIGNAL
Fis. 3Fig.4
8.
