Sony FDL-252T Service manual
SERVICE MANUAL
MODEL COMMANDER DEST. CHASSIS NO.
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FDL-252T US
MODEL COMMANDER DEST. CHASSIS NO.
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MICROFILM
∗ Please file according to model size. .......
2.5
LCD COLOR TV
FDL-252T
SPECIFICATIONS TABLE OF CONTENTS
Section Title Page
1. GENERAL
Power Sources (see fig. A) ...................................................... 3
Operation (see fig. B) .............................................................. 3
External Antenna Connection (see fig. C)............................... 4
Using with Video Equipment (see fig. D) ............................... 4
WARNING .............................................................................. 4
2. DISASSEMBLY
2-1. Case,A board and H board Removal ............................ 5
2-2. LCD Case and B board Removal ................................. 5
2-3. Service Position ............................................................ 5
3. CIRCUIT ADJUSTMENTS ............................................ 6
4. DIAGRAMS
4-1.Block Diagram (1)............................................................ 9
4-2.Block Diagram (2).......................................................... 11
4-3.Circuit Boards Location ................................................. 13
4-4.Printed Wiring Boards and Schematic Diagrams ........... 13
• A Board ....................................................................... 14
• B Board ....................................................................... 18
• H Board ....................................................................... 21
4-5.Semiconductors .............................................................. 22
5. EXPLODED VIEWS
5-1. Chassis Section .............................................................. 23
6. ELECTRICAL PARTS LIST........................................ 24
SHORT CIRCUIT THE ANODE OF THE PICTURE TUBE AND THE ANODE CAP TO THE METAL CHASSIS, CRT SHIELD, OR CARBON PAINTED ON THE CRT, AFTER REMOVING THE ANODE.
AN ISOLATION TRANSFORMER SHOULD BE USED DURING ANY SERVICE TO AVOID POSSIBLE SHOCK HAZARD, BECAUSE OF LIVE CHASSIS.
THE CHASSIS OF THIS RECElVER IS DIRECTLY CONNECTED TO THE
AC POWER LINE.
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY SHADING AND MARK ! ON THE SCHEMATIC DIAGRAMS, EXPLODED VIEWS AND IN THE PARTS LIST ARE
CRITICAL TO SAFE OPERATION. REPLACE THESECOMPONENTS
WITH SONY PARTS WHOSE PART NUMBERS APPEAR AS SHOWN IN
THIS MANUAL OR IN SUPPLEMENTS PUBLISHED BY SONY. CIRCUIT
ADJUSTMENTS THAT ARE CRITICAL TO SAFEOPERATION ARE IDENTIFIED IN THIS MANUAL. FOLLOW THESE PROCEDURES WHENEVER CRITICAL COMPONENTS ARE REPLACED OR IMPROPER OPERA-
TION IS SUSPECTED.
(CAUTION)
WARNING!!
– 2 –
SECTION 1
GENERAL
The operating instructions mentioned here are partial abstracts from the
Operating Instructions Manual. The page numbers of the Operating
Instruction Manual remain as in the manual. (Part no : 4-083-375-11)
– 3 –
– 4 –
SECTION 2
DISASSEMBLY
FDL-252T
2-1. CASE, A BOARD AND H BOARD REMOVAL
2 Two screws
(+PTP 2x8)
3 Screw
(+PTPWH 2)
Battery case (lower)
5 A board
1 Battery cover
lead wire (BLK)
lead wire (RED)
4 Remove
solder
6 H board
2-2. LCD CASE AND B BOARD REMOVAL
5 B board
4 LCD holder
3 LCD case (upper)
1 screw
(+PTP 2x8)
2 Hinge collar
2-3. SERVICE POSITION
AC power adaptor
7 Battery case (upper)
B board
J601
A board
CN401
CN301
CN201
H board
J101
Antenna
Cord
– 5 –
FDL-252T
JL12
75Ω 6dB
fo=45.75MHz±5kHz
SWEEP
MARKER
GENERATOR
0.01µF
ATT
SECTION 3
CIRCUIT ADJUSTMENTS
[SETUP](A BOARD )
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 Control R V550(VOL) and R V901(BRT) on the H board to their
mechanical centers.
[+5.0V ALIGNMENT (RV600)](A BOARD )
Using a digital voltmeter measuring the voltage between
JL09 (+5.0V) and JL87 (A.GND). Adjust RV600 to obtain
the value shown below.
Standard Value = 4.55V± 0.02VDC
S601 position = UHF position
[+30.0V CHECK](A BOARD )
Check the voltage across JL07 (+30.0V) and JL87 (A.GND) .
Standard Value = 32.5V±2.5VDC
[+7.5V CHECK](A BOARD )
Check the voltage across JL08 (+7.5V) and JL87 (A.GND) .
< A BOARD ALIGNMENT >
3-1.VIF.AFT ROUGH ALIGNMENT (T201, T202)
[SETUP]
1. Set S601 on the A board to VHF position.
2. Apply no signal to JL119 (RF).
3. Connect a 1 kΩ 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.
Fig. 3-1
Standard Value = 7.0V± 0.3VDC
[-10.0V CHECK](A BOARD )
Check the voltage across JL10 (-10.0V) and JL87 (A.GND) .
Standard Value = -9.8V± 0.6VDC
- A board - (Component side)
J601
EXT ANT
RV600
J601
DC IN JACK
RV002
RV001
RV201
RV004
RV003
T201
T202
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 position 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 waveform 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).
1Vp-p
45.75MHz
0
Fig. 3-2
– 6 –
3-2.AFT FINE ADJUSTMENT (T201)
1. Connect a 1 kilohm resistor between JL09 (+5.0V) and JL13
(RF AGC).
Note : Perform this adjustment as the last step in the
process since drift may occur due to aging.
2. Switch the sweep signal to CW.
fo= 45.75 MHz±5 kHz, -30±5dBm
Apply the abov e signal between JL12 (IF) and JL14 (IF GND)
and then make a fine adjustment of T201 so that the level be-
tween JL02 (AFT) and JL01 (D.GND) reaches2.2V±0.4VDC.
3. Remove the 1 kilohm resistor connected between JL09 (+5.0V)
and JL13 (RF AGC).
3-3.RF. AGC ALIGNMENT (RV201)
1. Set S601 to VHF position and receive a VHF color bar signal
issued from a signal generator.
2. Adjust RV201 and align the screen for the optimal point so
that the snow noise disappears.
3-4.CHANNEL DISPLAY POSITION ALIGNMENT (RV001, RV002, RV003, RV004)
1. Set S601 to VHF position, a potentiometer (47kΩ±15kΩ)
across JL06(CS) and JL09 (+5.0 V) as sho wn in Fig. 2-6 and
short the points JL04(CH CAL) and JL01 (D.GND).
2. Receive channel 2 and align the channel display positions with
RV002(VP).
3. Receive channel 13 and align the display bar with R V004(VA).
4. Align while performing tracking to mutual interference in the
above steps 2 and 3.
5. Receive channels 3 & 4 and confirm that the display bar is
within the standards.
6. Set S601 to UHF.
7. Receive channel 14 and align the display position with
RV001(UP).
8. Receive channel 69 and confirm that the display bar is within
the standards. If not within standards, align with R V003 so it
is within standards.
Once again receive channel 14 and confirm that the display bar
is within the standards.
Note : Use caution since shifting channel 69 will also
cause channel 14 to shift.
9. Remove the potentiometer (47kΩ+15kΩ) you connected between JL06(CS) and JL09(+5.0V). Also remov e the short you
connected between points JL04 (CH CAL)and JL01(D.GND).
JL06 (CS)
JL09(+5.0V)
Display bar
< B BOARD ALIGNMENT >
- B board (Component side)
RV306
RV301
RV302
RV308
3-5.V COM ALIGNMENT (RV302, RV306)
1. Adjust BRT VR (RV901) to1.740±0.005VDC, between
JL301(BRT) and JL307 (A.GND).
2. Observe the waveform across JL411 (V COM) and
JL407(GND).
3. Adjust RV302 (COM AMP) and RV306 (V COM DC) so that
the waveform resembles that in Fig. 3-5.
Note : The voltage at pin 37 (COMMON AMP) of IC302 shall
be a minimum of 1.8V.
5.0V±0.1Vp-p
0V
Fig. 3-5
-1.4V±0.1Vp-p
3-6.CONTRAST ALIGNMENT (RV301)
1. Receive the stepped waveform signal in 10 steps.
2. Observe the waveform across JL421(VG) and JL407(GND).
3. Align RV301 (CONT) so that 100IRE section matches the
standard below. (Fig. 3-6)
10thstep
(100IRE)
3.0V±0.1Vp-p
Fig. 3-6
3-7.COLOR PHASE (TINT) ALIGNMENT (RV308)
1. Receive the color bar signal from the signal generator.
2. Observe the waveform across JL422(VB) and JL407(GND).
3. Adjust RV308 (TINT) so that the waveform level resembles
that of Fig. 3-7.
Align so the portion is parallel and linear.
MEMO
15kΩ
VR(47kΩ)
Channel No.
6
*Channel No. and display
bar are to be in line.
Fig. 3-4
– 7 –
Fig. 3-7
– 8 –
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