FDL-252T - Sony TV Service Manual (repair manual). Page 6

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1. Apply a DC voltage of 4.5V

±

0.1V to the J601 terminal (DC

    input jack) on the A board.
2. With S601 on the A board at UHF position, set the User Con-

trol RV550(VOL) and RV901(BRT) on the H board  to their
mechanical centers.

Using a digital voltmeter measuring the voltage between
JL09 (+5.0V) and JL87 (A.GND). Adjust RV600 to obtain
the value shown below.

±

Check the voltage across JL07 (+30.0V) and JL87 (A.GND) .

±

Check the voltage across JL08 (+7.5V) and JL87 (A.GND) .

±

Check the voltage across JL10 (-10.0V) and JL87 (A.GND) .

±

[

SETUP

]

1. Set S601 on the A board to VHF position.
2. Apply no signal to JL119 (RF).
3. Connect a 1 k

Ω

 resistor between JL09 (+5.0V) and

    JL13 (RF AGC).
4. Apply a sweep signal across JL12 (IF) and JL14(IF GND).

(Fig. 3-1)

Note

 : Set the sweep signal for JL12 to -30

±

5dBm. Keep the

distance to the ATT output  JL12 as short as possible.

1. Connect an oscilloscope between JL86  (VIDEO) and JL87

(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 JL26 (MGC) external voltage for approximately

       a 1.0 Vp-p. Make sure that the JL26 (MGC) external
       voltage does not exceed 4.3VDC.
2. Remove the external voltage (MGC) from JL26.
3. Connect an oscilloscope between JL02 (AFT) and JL01

(D.GND) and make a rough 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 JL09 (+5.0V)

and JL13 (RF AGC).

JL12

75

Ω

 6dB

fo=45.75MHz

±

5kHz

SWEEP
MARKER
GENERATOR

0.01

µ

F

ATT

1Vp-p

45.75MHz

0

RV600

RV002

RV001

RV201

RV004

RV003

J601

DC IN JACK

J601

EXT ANT

T201

T202

- A board - (Component side)