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LT-3780D
Service Manual
60 pgs2.71 Mb0

Mitsubishi LT-3780D, LT-3780, LT-3280D, LT-3280 Service Manual

20052005
2005
20052005
Ser
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MITSUBISHI ELECTRIC
ManualManual
Manual
ManualManual
LIQUID CRYST AL DISPLA Y TELEVISION
LT-3280 (LT-3280D) LT-3780 (LT-3780D)
The LT -3280 includes the L T -3280D, monitor and HD-4001, receiver/controller. The LT -3780 includes the L T -3780D, monitor and HD-4001, receiver/controller. This manual covers the L T-3280D and L T -3780D, monitors. For the receiver/controller, see the HD-4001 Service Manual.
CAUTION:
Before servicing this chassis, it is important that the service person read the "SAFETY PRECAUTIONS" and "PRODUCT SAFETY NOTICE" contained in this manual.
SPECIFICATIONS
• Power : AC 120V , 60Hz
[LT-3280D] 200W [LT-3780D] 300W Standby <5W
• LCD Panel : Size/Resolution ­[LT-3280D] 32" diagonal, 16:9 / 1366x768 [LT-3780D] 37" diagonal, 16:9 / 1920x1080
: Pixel Pitch -
[LT-3280D] 0.519mm x 0.173mm x RGB [LT-3780D] 0.4275mm x 0.1425mm x RGB
• Input Jacks : MonitorLink™ Audio/Video - HDMI™
: MonitorLink™ Control - RS-232C : PC Video - VGA /Mini D-sub 15 pin : PC Audio - 3.5mm Mini-Jack
• Speakers : 2 Way Bass Reflex Left & Right (2 X 5W)
•
Cabinet Dimensions / We ight
LT-3280D
W i th Stand: Height Width Depth Weight
25.4" 32.4 " 12.8" 68. 0 lbs
W / O S t an d: Height W id th Dept h Wei ght
22.9" 32.4 " 5.0" 44.3 lbs
LT-3780D
W i th Stand: Height Width Depth Weight
28.5" 37.3 " 12 .8" 8 0.0 lbs
W / O S t an d: Height W id th Dept h Wei ght
26.0" 37.3 " 5.3" 57.3 lbs
• Weight and dimensions shown are approximate.
• Design specifications are subject to change without notice.
• HDMI™ is a trademark of HDMI Licensing, LLC
MITSUBISHI DIGITAL ELECTRONICS AMERICA, INC.
9351 Jeronimo Road, Irvine, CA 92618-1904
Copyright © 2005 Mitsubishi Digital Electronics America, Inc.
All Rights Reserved
MODELS: LT-3280D/LT-3780D
CONTENTS
PRODUCT SAFETY NOTICE & SAFETY PRECAUTIONS..................................................................5
DISASSEMBL Y
Disassembly & Panel Replacement ................................................................................................7
L T-3280 Wire Dressing .................................................................................................................. 23
L T-3780 Wire Dressing .................................................................................................................. 24
ELECTRICAL ADJUSTMENTS
Initial Setup................................................................................................................................... 25
CIRCUIT EXPLANA TIONS & BLOCK DIAGRAMS
Circuit Explanations...................................................................................................................... 27
Block Diagrams ............................................................................................................................32
TROUBLESHOOTING
Power Troubleshooting ..................................................................................................................35
Video Troubleshooting................................................................................................................... 38
Audio Troubleshooting................................................................................................................... 40
Remote Control Troubleshooting ................................................................................................... 42
Front Switch Troubleshooting........................................................................................................ 43
REPLACEMENT P ARTS
L T-3280 Replacement Parts List.................................................................................................... 44
L T-3780 Replacement Parts List.................................................................................................... 45
SCHEMA TICS
Page 3
MODELS: LT-3280D/LT-3780D
Page 4
MODELS: LT-3280D/LT-3780D
PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in television receivers have special safety related characteristics. These character­istics are often not evident from visual inspection nor can the protection afforded by them necessarily be obtained by using replacement components rated for higher voltage, wattage, etc.
Replacement parts which have special safety characteristics are identified in this service manual.
The replacement for any safety part should be identical in value and characteristics.
SAFETY PRECAUTIONS
NOTICE: Observe all cautions and safety related notes located inside the receiver cabinet and on the
receiver chassis.
WARNING:
1. Operation of this receiver outside the cabinet or with the cover removed presents a shock hazard from the receiver's power supplies. Work on the receiver should not be attempted by anyone who is not thoroughly familiar with the precautions necessary when working on high voltage equipment.
2. Do not install, remove or handle the LCD panel in any manner unless shatterproof goggles are worn. People not so equipped should be kept away while the panel is being handled. Keep the panel away from the body while handling.
3. When service is required, observe the original lead dress. Where a short-circuit has occurred, replace those components that indicate evidence of overheating.
Leakage current check
Before returning the receiver to the customer, leakage current should be measured using following methods.
1. Cold Check
With the alternating current (AC) plug removed from the AC source, place a jumper across the two AC plug prongs.
Connect one lead of an ohm meter to the AC plug and touch the other lead to each exposed met al part (i.e. anten­nas, handle bracket, metal cabinet, screw heads, metal overlay , control shafts, etc.), p articularly any exposed metal part that has a return path to the chassis. The resistance of the exposed metal parts having a return path to the chassis should be a minimum of 1Meg Ohm. Any resistance below this value indicates an abnormal condition and requires corrective action.
2. Hot Check ...Use the circuit shown below to perform the hot check test.
1. Keep switch S1 open and connect the receiver to the measuring circuit. Immediately after
connection, and with the switching devices of the receiver in their operating positions, measure
the leakage current for both positions of switch S2.
2. Close switch S1, energizing the receiver . Immediately after closing switch S1, and with the
switching devices of the receiver in their operating positions, measure the leakage current for both positions of switch S2. Repeat the current measurements of items 1 and 2 after the receiver has
reached thermal stabilization. The leakage current must not exceed 0.5 milliampere (mA).
Page 5
MODELS: LT-3280D/LT-3780D
Page 6
MODELS: LT-3280D/LT-3780D
DISASSEMBLY & PANEL REPLACEMENT PROCEDURE
1. REMOVE AV1, A V2, DTV & STAND COVERS.
AV1-COVER
AV2-COVER
STAND-FRAME-COVER
DTV-COVER
2. PLACE SET F ACE DOWN ON A SOFT CUSHION, WITH THE ST AND HANGING OVER THE EDGE OF THE TABLE.
3. REMOVE ST AND-KIT .
S20：SCREW PH+SW+W M6*21.5
Page 7
4. REMOVE BACK COVER KIT .
MODELS: LT-3280D/LT-3780D
S5
S5
S5
S5 S5
S5
S14：SCREW FPH M 3*8
S5
S14
S10：SCREW IH M4*8
S5
S14
S5S5
SCREW WIT H ST AY -STAND
SCERW WIT H CABL E -CL AM P 2 POINTS
F07:CABLE-CLAMP
S5
S5
S5：SCREW BH 4*16TP-P
S5
S5
S3：SCREW BH M 4*10
S3：SCREW BH M4*10
14 PCS
Page 8
MODELS: LT-3280D/LT-3780D
5. REMOVE WALL MOUNT BRACKET
S9：SCREW PH W M 3*6
S16：SCREW B H +SW M6* 12
REM OVE WAL L-M OU N T-BK T , WHILE DEPRESSING THE HAN GING PART OF P OWER- B KT BE L O W.
LT-3780D S5：SCREW BH 4*16TP-P
LT-3280D S8：SCREW BH 4*12TP-P
6. REMOVE SHIELD-POWER-SUB & SHIELD-CASEMAIN.
SHIELD-CASE-MAIN
S9：SCREW PH W M 3 *6
SHIELD-POWER-SUB
S9：SCREW PHW M3*6
Page 9
MODELS: LT-3280D/LT-3780D
7A. (L T -3280D)
(NOT NECESSARY FOR P ANEL REPLACEMENT)
REMOVE: a. PLA TE-MAIN-SIDE b. SERVICE-KIT c. PLA TE-MAIN-BOTTOM d. PLA TE-POWER-BOTTOM
SERVICE-KIT (SA-PWB-SERV ICE)
PLATE-POWER-BOTTOM
PLATE-MAIN-SIDE
PLATE-MAIN-BOTTOM
S11：SCREW IH M3*6
S9：SCREW PH W M 3 *6
PLATE-POWER-BOTTOM
S15：SCREW_HH+SW _UNC4#-40*7_H5
Page 10
7B. (L T-3780D) REMOVE:
a. PLA TE-MAIN-SIDE b. SERVICE-KIT c. PLA TE-MAIN-BOTTOM d. (NOT NECESSARY FOR
P ANEL REPLACEMENT)
PLATE-POWER-BOTTOM
PLATE-MAIN-SIDE
MODELS: LT-3280D/LT-3780D
SERVICE-K IT
(SA-PWB -SERVICE)
PLATE-POWER-BOTTOM NOT NECESSARY FOR PANEL REPLACEMENT
S9：SCREW PH W M 3 *6
PLATE-MAIN-B OTTOM
S11：SCREW IH M3*6
PLATE-POWER-BOTTOM
S15：SCREW_HH+SW _UNC4#-40*7_H5
Page 11
MODELS: LT-3280D/LT-3780D
8. (L T-3780D ONL Y) REMOVE SHIELD-INVERTER
S9：SCREW PH W M 3*6
S5：SCREW BH 4*16TP-P
ITEM 144: AL-TAPE It sti ck s on the position of a fig ure.
Page 12
9. REMOVE FUNCTION-KEY -KIT
10. REMOVE IR-KIT
MODELS: LT-3280D/LT-3780D
S6：SCREW BH 3*12 TP-P
11. REMOVE SA-PWB-LED
S4：SCREW BH 3*8 TP-P
S4：SCREW BH 3*8 TP-P
Page 13
MODELS: LT-3280D/LT-3780D
12. REMOVE POWER-KIT & SPEAKER CONNECTOR
SPEAKER-CONNECTER
POWER-KIT
S4：SCREW BH 3*8 TP-P
13A. (L T -3280D)
S17：SCREW PH +SW+ T W M 3 *6
(NOT NECESSARY FOR P ANEL REPLACEMENT)
REMOVE: a. A-PWB-MAIN 2 b. SA-PWB-POWER c. A-PWB-POWER-SUB2
A-PWB-MAIN_2 SA-PWB-POWER A-PWB-POWE R-SUB 2
13 PCS 8 PCS
5 PCS
Page 14
13B. (L T -3780D)
REMOVE: a. A-PWB-MAIN 2 b. SA-PWB-POWER c. A-PWB-POWER-SUB2
S17：SCREW PH +SW+ T W M 3 *6
MODELS: LT-3280D/LT-3780D
(NOT NECESSARY FOR PANEL REPLACEMENT)
A-PWB-MAIN_1
13 PCS
SA-PWB-POWER NOT NE CE SSA RY FOR P ANEL REPLACEMENT
8 PCS
A-PWB-POW ER-SUB1
7 PCS
Page 15
MODELS: LT-3280D/LT-3780D
14. (L T -3780D) REMOVE P ANEL_BKT
S5：SCREW BH 4*16TP-P
S2：SCREW BH M4*5.5
RE MOVE CNF1/CNF2/ CN 1/CN2-L EAD to the panel side not to be caught by PANEL -B K T.
S2：SCREW BH M 4*5.5
AT TACH AL -TAP E
144 143
S5：SCREW BH 4*16TP-P
Page 16
MODELS: LT-3280D/LT-3780D
15A. (L T -3280D) REMOVE FRONT -KIT & SPEAKER
S8：SCREW BH 4*12TP-P
Screw with GND-W ire (50mm).
15B. (L T -3780D) REMOVE FRONT -KIT & SPEAKER
CAUTION: UP AN D DOWN DIRECTION OF PANE L IS AGAINST LABEL AND ARROW MARK OF PANEL.
S5：SCREW BH 4*16TP-P
Screw with GND-Wire (90mm).
Page 17
MODELS: LT-3280D/LT-3780D
16. (L T-3280D) REMOVE P ANEL_BKT
S1：SCREW PH M4*12
REMOVE CNF1/CN1/CN2-LEAD first and push in under PANEL-BKT for easy removal.
Top & Bottom is same. 4 PCS (2x2)
S2：SCREW BH M4*5.5
17. (LT-3280D) FOR RE-ASSEMBL Y AFTER P ANEL REPLACEMENT, REVERSE THE DISASSEMBL Y PROCEDURE. CONTINUE FOR L T -3780D PANEL REPLACEMENT AND FURTHER DISASSEMBL Y INSTRUCTIONS.
Page 18
CAUTION: UP AND D OW N DIRECTION OF PANEL IS AGAINST LABEL AND A RROW MARK OF PANEL.
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