Sanyo AVM-2751S User manual

AS
FILE NO.
SERVICE MANUAL Remote Control Color
Television AVM-2751S (U.S.A.)
ORIGINALVERSION
Chassis No. G7V-2751S0
NOTE: Match the Chassis No. on
the unit’s back cover with
the Chassis No. in the
Service Manual.
If the Original Version
Service Manual Chassis
No. does not match the
unit’s, additional Service
Literature is required.You
must refer to “Notices” to the
Original Service Manual
prior to servicing the unit.
Contents
Safety Instructions . . . . . . . . . . . . . . . . . . 2
Service Adjustments. . . . . . . . . . . . . . 3 - 9
Service Hints. . . . . . . . . . . . . . . . . . . . . . 10
Mechanical Disassemblies. . . . . . . . . . . 11
Chassis Electrical Parts List . . . . . . 12 - 19
Cabinet Parts List . . . . . . . . . . . . . . . . . . 20
Component and Test Point
Locations . . . . . . . . . . . . . . . . . . . 21 - 23
Schematic Insert . . . . . . . . . . . . . . . 25 - 32
Schematic Notes . . . . . . . . . . . . . . . . . 25
Pin Layouts . . . . . . . . . . . . . . . . . . . . . 25
Capacitor and Resistor Codes . . . . . . 25
Block Diagram. . . . . . . . . . . . . . . 26 - 27
Voltage Charts . . . . . . . . . . . . . . . 26 - 27
Waveforms. . . . . . . . . . . . . . . . . . . . . . 28
Schematic Diagrams . . . . . . . . . . 29 - 32
Specifications
Power Rating . . . . . . . . . . . . . . . . . . . . . 120V, 60Hz
86W (Avg), 2.5A (Max)
Antenna Input Impedance . . . . . . . . . . . . . . . . 75W
UHF/VHF/CATV
Receiving Channel . . . . . . . . . . . . . . . . 2 - 13 (VHF),
14 - 69 (UHF),
01, 14-94, 95-125 (CATV)
Remote Ready . . . . . . . . . . 24 Key Remote Control
Sound Output . . . . . . . . . . . . . . . . . . . . . . 1.0 W/CH
Intermediate Frequency
Picture IF Carrier. . . . . . . . . . . . . . . . . . 45.75MHz
Sound IF Carrier . . . . . . . . . . . . . . . . . . 41.25MHz
Color Sub Carrier . . . . . . . . . . . . . . . . . 42.17MHz
Picture Tube . . . . . . . . . . . . . . . . . . . A68ADT25X03
Semiconductors
Integrated Circuits. . . . . . . . . . . . . . . . . . . . . . . . 9
Transistors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Except within Tuner and RC Pre-Amp.
Cabinet Dimensions
Width. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 664mm
Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . 589mm
Depth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 522mm
REFERENCE No. SM780072
AVM-2751S, G7VCM, PRODUCT CODE 111355582
AS
MTS
VIDEO IN L-AUDIO-R

— 2 —
SAFETY PRECAUTIONS
WARNING: The chassis of this receiver has a floating
ground with the potential of one half the AC line voltage in
respect to earth ground. Service should not be attempted by
anyone not familiar with the precautions necessary when
working on this type of equipment.
The following precautions must be observed:
1. An isolation transformer must be connected in the power
line between the receiver and the AC line before any ser-
vice is performed on the receiver.
2. Comply with all caution and safety-related notes provided
on the side of the cabinet, inside the cabinet, on the chas-
sis, and the picture tube.
3. When replacing a chassis in the cabinet, always be certain
that all the protective devices are installed properly, such
as control knobs, adjustment covers, shields and barriers.
DO NOT OPERATE THIS TELEVISION RECEIVER
WITHOUT THE PROTECTIVE SHIELD IN POSITION AND
PROPERLY SECURED.
4. Before replacing the back cover of the set, thoroughly
inspect the inside of the cabinet to see that no stray parts
or tools have been left inside.
Before returning any television to the customer, the
service technician must perform the following safety
checks to be sure that the unit is completely safe to
operate without danger of electrical shock.
ANTENNA COLD CHECK
Remove AC plug from the 120 VAC outlet and place a
jumper across the two blades. Connect one lead of an ohm-
meter to the jumpered AC plug, and touch the other lead to
each exposed antenna terminal (UHF and VHF antenna ter-
minals). The resistance must measure between 1M ohm and
5.2M ohm. Any resistance value below or above this range
indicates an abnormality which requires corrective action.
LEAKAGE CURRENT CHECK
Plug the AC line cord directly into a 120 VAC outlet. (Do not
use an isolation transformer for this check.) Use an AC volt-
meter, that has 5000 ohms per volt or more sensitivity.
Connect a 1500 ohm 10 watt resistor, paralleled by a 0.15 µF
150 VAC capacitor, between a known good earth ground
(water pipe, conduit, etc.) and all exposed metal parts of the
cabinet (antennas, handle bracket, metal cabinet, screw
heads, metal overlays, control shafts, etc.). Measure the AC
voltage across the 1500 ohm resistor. The AC voltage
should not exceed 750 mV. A reading exceeding 750 mV
indicates that a dangerous potential exists. The fault must
be located and corrected. Repeat the above test with the
receiver power plug reversed.
NEVER RETURN A RECEIVER TO THE CUSTOMER
WITHOUT TAKING THE NECESSARY CORRECTIVE ACTION.
X-RADIATION PRECAUTION
The primary source of X-RADIATION in solid-state receivers is
the picture tube. The picture tube is specially constructed to
limit X-Ray emission. For continued X-RADIATION protection,
the replacement tube must be the same type as the original
(including the suffix letter in the part numbers). Excessive high
voltage may produce potentially hazardous X-RADIATION. To
avoid such hazards, the high voltage must be maintained within
specific limits. Refer to the X-RADIATION WARNING NOTE on
the CHASSIS SCHEMATIC in this service manual for specific
high voltage limits. If the high voltage exceeds specified limits,
check the components specified on the chassis schematic
diagram and take the necessary corrective action. Carefully
follow the instructions for the +B Voltage Check and the High
Voltage Check to maintain the high voltage within the specified
limits.
HIGHVOLTAGE HOLD-DOWNTEST
To prevent X-RADIATION from the picture tube due to
excessive high voltage, a HOLD-DOWN circuit is provided in
the high voltage circuit. Every time the receiver is serviced,
the high voltage HOLD-DOWN circuit must be tested for
proper operation. Refer to the HIGH VOLTAGE HOLD-
DOWN TEST in service adjustments.
PRODUCT SAFETY NOTICE
When replacing components in a receiver, always keep in
mind the necessary product safety precautions. Pay special
attention to the replacement of components marked with a
star (★) in the parts list and in the schematic diagrams. To
ensure safe product operation, it is necessary to replace
those components with the exact same PARTS.
SAFETY INSTRUCTIONS
0.15 µF 150V AC
1500 ohm
10 watt
Good earth ground
such as a water pipe,
conduit, etc.
AC OUTLET
TELEVISION
RECEIVER
READING SHOULD NOT EXCEED 750 mV.
AC VOLTMETER
(5000 ohms per volt or more sensitivity)
To be touched to all of exposed metal parts.
Voltmeter Hook-up for Leakage Current Check.

GENERAL
Thisset has an On-screen Service Menu systemincluded in the CPU that allows remoteoperation for most of the service adjustments.
ON-SCREEN SERVICE MENU SYSTEM
1. Enter the Service Menu:
•While pressing the MENU key, reconnect the AC power cord. The Service Menu Display will now appear. (See Figure 1.)
2. Service Adjustments:
•Press the ▲or ▼key to select the desired service menu you want to adjust. (See page 4 for On-screen Service Menu.)
•Use the + or – key to adjust the data.
3. Exit from the Service Menu:
•Press the MENU key to turn off the Service Menu display.
SERVICE ADJUSTMENTS
— 3 —
IC802 (EEPROM) REPLACEMENT
When IC802 (EEPROM) is replaced, IC801 (CPU) will automatically write the initial reference data into IC802 for basic TV operation.
However, the bus data should be checked and some bus data should be set up before attempting the service adjustments.
(See pages 4 – 6 for detailed information.)
INITIAL BUS DATA SETUP
Note: When IC802 (EEPROM) is replaced, the Service Menu NO. 03 HP (H Phase), NO. 05 VPO (V Position), NO. 07 VLN
(V Lin), NO. 10 VSC (V S Correction), NO. 14 VC (V Comp), NO. 21 SBI (Sub Bias), NO. 24 FLS (Filter System),
NO. 28 PRE (Preshoot Adj), NO. 29 WP (White Peak Limiter), NO. 32 BSG (Black Str Gain), NO. 34 DCR (DC Reset),
NO. 37 AF (Auto Flesh), NO. 41 RYA (R-Y/B-Y Angle), NO. 55 STI ( Sub Tint), NO. 56 SSH (Sub Sharp), NO. 57 OPT
(SA Option ), NO. 58 OP2 (SA Option 2), NO. 59 HR (OSD Position), NO. 60 ATT (Input Level), and NO. 63 SBO (Sub
Bright Offset) should be set up for proper TV operation before attempting the service adjustments.
1. Disconnect the AC power cord (AC 120V line).
2. While pressing the MENU key, reconnect the AC power cord. The Service Menu display will now appear.
3. Select NO. 03 HP (H Phase) with ▲or ▼key. Adjust the data with + or – key for 8.
4. Select NO. 05 VPO (V Position) with ▲or ▼key. Adjust the data with + or – key for 25.
5. Select NO. 07 VLN (V Lin) with ▲or ▼key. Adjust the data with + or – key for 15.
6. Select NO. 10 VSC (V S Correction) with ▲or ▼key. Adjust the data with + or – key for 13.
7. Select NO. 14 VC (V Compression) with ▲or ▼key. Adjust the data with + or – key for 7.
8. Select NO. 21 SBI (Sub Bias) with ▲or ▼key. Adjust the data with + or – key for 54.
9. Select NO. 24 FLS (Filter System) with ▲or ▼key. Adjust the data with + or – key for 1.
10. Select NO. 28 PRE (Preshoot Adj) with ▲or ▼key. Adjust the data with + or – key for 3.
11. Select NO. 29 WP (White Peak Limiter) with ▲or ▼key. Adjust the data with + or – key for 2.
12. Select NO. 32 BSG (Black Str Gain) with ▲or ▼key. Adjust the data with + or – key for 2.
13. Select NO. 34 DCR (DC Reset) with ▲or ▼key. Adjust the data with + or – key for 1.
14. Select NO. 37 AF (Auto Flesh) with ▲or ▼key. Adjust the data with + or – key for 1.
15. Select NO. 41 RYA (R-Y/B-Y Angle) with ▲or ▼key. Adjust the data with + or – key for 2.
16. Select NO. 55 STI (Sub Tint) with ▲or ▼key. Adjust the data with + or – key for 19.
17. Select NO. 56 SSH (Sub Sharp) with ▲or ▼key. Adjust the data with + or – key for 8.
18. Select NO. 57 OPT (SA Option ) with ▲or ▼key. Adjust the data with + or – key for 0.
19. Select NO. 58 OP2 (SA Option 2) with ▲or ▼key. Adjust the data with + or – key for 98.
20. Select NO. 59 HR (OSD Position) with ▲or ▼key. Adjust the data with + or – key for 20.
21. Select NO. 60 ATT (Input Level) with ▲or ▼key. Adjust the data with + or – key for 7.
22. Select NO. 63 SBO (Sub Bright Offset) with ▲or ▼key. Adjust the data with + or – key for 2.
23. Press the MENU key to turn off the Service Menu display.
NO. DATA
XX OPT XXX XXXXXXXX
Figure 1. Service Menu Display
ITEM NO.
TITLE BINARY DATA
(8 bit)
DECIMAL DATA

— 4 —
Table 1. ON-SCREEN SERVICE MENU
When IC802 (EEPROM) is replaced, check the bus data to confirm they are the same as below. The shaded menu should be
checked and be set up or readjusted according to the procedures described in the following pages. Initial Setup Data marked
with an * should be changed from Initial Reference Data. (See page 3 for Initial Bus Data Setup.)
NO. TITLE INITIAL REFERENCE INITIAL SETUP RANGE OF DATA FUNCTION
DATA DATA
01 HFR 29 29 0~63 Horizontal Frequency
02 AFC 0 0 0, 1 AFC Gain & Gate
03 HP 11 8* 0~31 Horizontal Phase (Horizontal Centering)
04 VS 64 64 0~127 Vertical Size
05 VPO 32 25* 0~63 Vertical Position
06 VSP 0 0 0, 1 Vertical Set Up (Sync Sensitivity)
07 VLN 17 15* 0~31 Vertical Linearity
08 CRS 0 0 0~3 Cross B/W
09 GRY 1 1 0, 1 Gray Mode
10 VSC 10 13* 0~31 Vertical S Correction
11 HBR 3 3 0~7 H BLK R
12 HBL 4 4 0~7 H BLK L
13 CDM 0 0 0, 1 C D Mode
14 VC 5 7* 0~7 Vertical Compression
15 RB 0 0 0~255 Red Bias
16 GB 0 0 0~255 Green Bias
17 BB 0 0 0~255 Blue Bias
18 RD 64 64 0~127 Red Drive
19 GD 8 8 0~15 Green Drive
20 BD 64 64 0~127 Blue Drive
21 SBI 64 54* 0~127 Sub Bias
22 OSD 2 2 0~3 OSD Contrast
23 POS 0 0 0, 1 Pre/Over SW
24 FLS 2 1* 0~7 Filter System
25 CKO 3 3 0~7 Color Killer Operation
26 GYA 0 0 0, 1 G-Y Angle
27 CRG 2 2 0~3 Coring Gain
28 PRE 1 3* 0~3 Pre Shoot Adjust
29 WP 0 1* 0, 1 White Peak Limiter
30 FSW 0 0 0, 1 FBP Blanking Switch
31 VBL 0 0 0, 1 Vertical Blanking Switch
32 BSG 1 2* 0~3 Black Str Gain
33 BSS 1 1 0~3 Black Str Start
34 DCR 0 1* 0~3 DC Reset
35 YGM 1 1 0~3 Y Gamma
36 CBP 0 0 0, 1 C Bypass
37 AF 0 1* 0, 1 Auto Flesh
38 BAT 4 4 0~7 Bright ABL Threshold
39 MSD 0 0 0, 1 Mid Stop Def
40 ABL 0 0 0, 1 Auto Bright Limit
41 RYA 4 2* 0~15 R-Y/B-Y Angle
42 RAD 20 20 0~63 RF AGC Delay
43 IAS 0 0 0, 1 IF AGC
44 FMM 0 0 0, 1 FM Mute
45 FL 15 15 0~31 FM Level

— 5 —
Table 1. ON-SCREEN SERVICE MENU (Continued)
When IC802 (EEPROM) is replaced, check the bus data to confirm they are the same as below. The shaded menu should be
checked and be set up or readjusted according to the procedures described in the following pages. Initial Setup Data
marked with an * should be changed from Initial Reference Data. (See page 3 for Initial Bus Data Setup.)
NO. TITLE INITIAL REFERENCE INITIAL SETUP RANGE OF DATA FUNCTION
DATA DATA
46 VL 4 4 0~7 Video Level
47 EWD 39 39 0~63 EW DC
48 EWA 30 30 0~63 EW Amp
49 EWT 34 34 0~63 EW Tilt
50 EWP 7 7 0~7 EW Corner Top
51 EWB 8 8 EW Corner Bottom
52 HSC 4 4 Horz Size Comp
53 SB 32 32 0~63 Sub Bright
54 SCO 7 7 0~31 Sub Color
55 STI 20 19* 0~31 Sub Tint
56 SSH 12 8* 0~31 Sub Sharpness
57 OPT 0 0 0~255 Option (See Note 1 page 6.)
58 OP2 0 98* 0~255 Option 2 (See Note 2 page 6.)
59 HR 24 20* 0~63 OSD Horizontal Position
60 ATT 10 7* 0~63 Input Level
61 WDB 32 32 0~63 Wideband
62 SPC 32 32 0~63 Spectral
63 SBO 5 2* 0~255 Sub Bright Offset
64 PCO 40 40 0~63 PIP Color
65 PTI 40 40 0~63 PIP Tint
66 PUV 24 24 0~63 PIP Top Position
67 PDV 147 147 0~255 PIP Bottom Position
68 PLH 10 10 0~63 PIP Left Position
69 PRH 101 101 0~255 PIP Right Position
70 PCN 52 52 0~63 PIP Y Level
71 PBS 15 15 0~63 PIP BGP Phase
72 DRV 64 64 0~127 Red Drive Adjustment (See Note 3 page 6.)
64 64 0~127 Blue Drive Adjustment (See Note 3 page 6.)
– 0 0 0~255 Red Bias Adjustment (See Note 4 page 6.)
73 – 0 0 0~255 Green Bias Adjustment (See Note 4 page 6.)
– 0 0 0~255 Blue Bias Adjustment (See Note 4 page 6.)