Sony FDL-PT22/JE Service Manual page 9

45.75MHz
Fig.3-2
(3) Remove the external voltage (MGC) from JL51.
(4) Connect the output between JL31 (AFT) and JL30 (D.GND) to
an oscilloscope, and roughly adjust T201 so that the position
of 45.75MHz will be a zero cross.
(5) Remove 1k from the section between JL77 (4.5V) and JL28
(RF AGC).
AFT ADJUSTMENT
(1) Insert 1k between JL77 (4.5V) and JL28 (RF AGC).
Note: Because of drifting due to aging, adjustment should
be made at the end of the process.
(2) Switch the sweep signal to CW.
fo = 45.75MHz 5kHz
Input the above signal to the section between JL26 (IF) and
JL27 (IF GND), and finely adjust T201 so that the level be-
tween JL31 (AFT) and JL30 (D.GND) will be 2.2
(3) Remove 1k from the section between JL77 (4.5V) and JL28
(RF AGC).
RF.AGC ADJUSTMENT
(1) Input the VHF color bar signal from the test signal generator.
Approx. 1.0Vp
(2) Adjust RV201 to optimum position so that there is no snow
CHANNEL DISPLAY POSITION ADJUSTMENT
(1) Set S601 in the VHF position.
(2) Receive 2ch, and adjust the channel display position with
(3) Receive 13ch, and adjust the display bar with RV004.
(4) Carry out tracking, because (2) and (3) interfere with each other.
(5) Receive 6 and 7ch, and check that the display bar conforms to
(6) Set S601 in the UHF position.
(7) Receive 14ch and adjust the display position with RV001.
(8) Receive 40ch and 69ch, and check that the display bar con-
(9) Remove resistors from JL25 and JL77, and open the short cir-
0.4VDC.
– 9 –
noise on the screen.
Insert resistors (47k + 15k ) between JL25 and JL77 (4.5V
line), and short circuit JL21 and JL30 (D.GND).
RV002.
the standard.
forms to the standard.
cuit between JL21 and JL30
JL25
JL77
6
*Channel No. and display ber are to be in line.
Fig.3-3
15K
47K
Display bar
Channel No.