FDL-PT222 - Sony TV Service Manual (repair manual). Page 7

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Using a digital voltmeter measuring the voltage between
JL32 (+4.5V) and JL33 (GND). Adjust RV601 to obtain
the value shown below.

±

Check the voltage across JL29 (+30.0V) and JL33 (GND) .

±

1.  Feed the audio signal 1kHz 100% modulated.
2.  Set RV501 to maximum.
3.  Connect an oscilloscope between JL23 (SP) and JL15 (SP

GND).

4.  Check the waveform on the oscilloscope becomes the stan-

dard value.

[

SETUP

]

1. Set S601 on the A board to VHF position.
2. Apply no signal to JL18 (RF).
3. Connect a 1 k

Ω

 resistor between JL77 (+4.5V) and

    JL28 (RF AGC).
4. Apply a sweep signal across JL26 (IF) and JL27(IF GND).

(Fig. 3-1)

Note

 : Set the sweep signal for JL26 to -30

±

5dBm. Keep the

distance to the ATT output  JL26 as short as possible.

[ADJUSTMNT]
1. Connect an oscilloscope between JL72  (VIDEO) and JL71

(A.GND) and apply an external     voltage (MGC) to JL26 to
obtain a waveform as shown in Fig. 3-2 (make sure not to
clip the extremely short portion).Adjust T202 so that the po-
sition at 45.75 MHz is the lowest point.

Note

 : Align JL51 (MGC) external voltage for approximately

       a 1.0 Vp-p. Make sure that the JL51 (MGC) external
       voltage does not exceed 4.3VDC.
2. Remove the external voltage (MGC) from JL51.
3. Connect an oscilloscope between JL31 (AFT) and JL30

(D.GND) and make a coarse adjustment of T201 so that wave-
form is close to zero at the 45.75 MHz position.

4. Remove the 1 kilohm resistor connected between JL77 (+4.5V)

and JL28 (RF AGC).

JL26

75

Ω

 6dB

fo=45.75MHz

±

5kHz

SWEEP
MARKER
GENERATOR

0.01

µ

F

ATT

1Vp-p

45.75MHz

0

TU101

RV201

T201 T202

RV002

RV004

RV001

- T1 board - (Component side)