Sony HMK-70 - Page 8

HMK-70 ang
SECTION 3
ALIGNMENT AND ADJUSTMENT
3-1. FM I-F AND DISCRIMINATOR
ALIGNMENT (See page 9 for procedure.)
The ceramic filters used in the fm i-f
circuit are color coded according to their
specified center frequencies.
Specified
Part No. Center Freg. Color
1-527-220-11 10.70 MHz red
1-527-220-21 10.67 MHz blue
1-527-220-3 1 10.73 MHz orange
1-527-220-41 10.64 MHz black
1-527-220-5 1 10.76 MHz white
reir sy VERN rtarerer
UHL LLU
4} CTOO3 :
fm OSC trimmer q
ERS Bre
24) CTOS2 _- ,
BBP
Fig. 3-1. Interruption of fm or a-m local
oscillator operation
Note: Local oscillator should be killed when
performing this alignment. To stop the
local oscillator’s operation, shunt the
oscillator capacitor with a 0.022 uF ca-
pacitor as shown in Fig. 3-1.
Test Setup:
oscilloscope ac VTVM
rf
-
signal
|
IN
generator
rn
ie By ibid
CT002
frm rf trimmer
ks
i
Z
}
Fig. 3-3. Fm discriminator output connection