Sony SDM-U27M90 Users guide [bg, uk]
Dismantling Information forUse
by ProfessionalRecyclers
ORIGINAL MANUAL ISSUE DATE: 5/2022
Model:
SDM-U27M90
LCD Digital Color Monitor
Conditions of Use:
(1) Please use this information only for the purpose of performing repair and recycling Sony products.
Using this information for any purpose other than the purpose described foregoing is forbidden.
(2) Do not copy, replicate, reproduce, alter, translate, transmit, sell, lease, or distribute this information
in whole or in part without the prior written permission of the author.
Revision of Information:
This information may be changed or updated at any time without any prior notice. Please confirm that
this information is up-to-date before using it.
9-888-878-41
Sony Corporation
© 2022. 5
MODEL LIST/REVISION HISTORY
MODEL COLOR COMMANDER DEST.
SDM-U27M90 White CEI
SDM-U27M90
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SAFETY NOTE
1-1. Warnings and Caution
1) CAUTION :These servicing instructions are for use by qualified
service personnel only.
2) To reduce the risk of electric shock, do not perform any servicing other
than that contained in the operating instructions unless you are qualified to
do so.
3) WARNING!! : An isolation transformer should be used during any
service to avoid possible shock hazard, because of live chassis. The
chassis of this receiver is directly connected to the ac power line.
The replaceable fuse could be in the neutral of the mains supply. When
replacing the fuse, the mains shall be disconnected for de-energize the
phase conductors.
(*Except AC ADAPTOR, Because it does not carry out replacing an
internal fuse.)
4) CARRYING THE TV : Be sure to follow these guidelines to protect
your property and avoid causing serious injury :
• Carry the TV with an adequate number of people; larger size TVs
require two or more people.
•Correct hand placement while carrying the TV is very important
for safety and to avoid damages.
5) SAFETY-RELATED COMPONENT WARNING!! : Components
identified by shading and ! mark on the exploded views, and in the parts
list are critical for safe operation. Replace these components with Sony
parts whose part numbers appear as shown in this manual or in
supplements published by Sony. Circuit adjustments that are critical for
safe operation are identified in this manual. Follow these procedures
whenever critical components are replaced or improper operation is
suspected.
6) IMPORTANT REMINDER FOR TV MAINBOARD REPLACEMENT :
It is mandatory for service centers to confirm the TV‘s system information
after each repair carried out with Mainboard replacement.
Whenever a TV Main board is replaced, the correct TV Model and Serial
number must be reinserted into memory.
This is a MANDATORY procedure that each service center must apply.
Please refer to the chapter of ADJUSTMENT in this service manual to find
out how to set the model number and serial number in service mode.
1-2. Caution Handling of LCD Panel
When repairing the LCD Panel, make sure you are grounded with a wrist
band.
When repairing the LCD Panel on the wall, the panel must be secured
using the 4 mounting holes on the rear cover.
1) Do not press the panel or frame edge to avoid the risk of electric
shock.
2) Do not scratch or press on the panel with any sharp objects.
3) Do not leave the module in high temperature or in areas of high humidity
for an extended period of time.
4) Do not expose the LCD panel to direct sunlight.
5) Avoid contact with water. It may cause short circuit within the module.
6) Disconnect the AC power when replacing the backlight (CCFL) or
inverter circuit. (High voltage occurs at the inverter circuit at 650Vrms)
7) Always clean the LCD panel with a soft cloth material.
8) Use care when handling the wires or connectors of the inverter circuit.
Damaging the wires may cause a short circuit.
9) Protect the panel from ESD to avoid damaging the electronic circuit
(C-MOS).
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10) During the repair, DO NOT leave the Power On or Burn-in period for
more than 1 hour while the TV is face down on a cloth. Refer Figure 1.
Figure 1.
1-3. Caution_for_Board_handling
Symptom : The following problems will occur due to handling of the IC
mounted on the board.
Solder crack due to substrate handling (stress)
・
・
IC breakdown due to static electricity (ESD)
When repairing the TV at the customer‘s home or service station or
Repair of defect board, please pay attention to the handling of the board.
SAFETY NOTE
1-4. Caution About the Lithium Battery
1) Danger of explosion if battery is incorrectly replaced. Replace only
with the same or equivalent type.
2) Outer case broken battery should not contact to water.
1-5. Safety Check-Out
After correcting the original service problem, perform the following
safety checks before releasing the set to the customer:-
1) Check the area of your repair for unsoldered or poorly soldered
connections. Check the entire board surface for solder splashes and
bridges.
2) Check the inter board wiring to ensure that no wires are pinched or
contact high-wattage resistors.
3) Check all control knobs, shields, covers, ground straps and mounting
hardware have been replaced. Be absolutely certain you have replaced
all the insulators.
4) Look for unauthorized replacement parts, particularly transistors that
were installed during a previous repair. Point them out to the customer
and recommend their replacement.
5) Look for parts which, though functioning show obvious signs of
deterioration. Point them out to the customer and recommend their
replacement.
6) Check the line cords for cracks and abrasion. Recommend the
replacement of any such line cord to the customer.
7) Check the antenna terminals, metal trim, metalized knobs, screws and
all other exposed metal parts for AC leakage. Check leakage test as
described next.
8) For safety reasons, repairing the Power board and/or Inverter board is
prohibited.
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SAFETY NOTE
1-6. Leakage Test
(To protect electric shock when customer touch the terminal.)
Leakage current can be measured by V: Voltmeter or oscilloscope
(r.m.s. or peak reading)
Stabilized power supply instrument and isolated voltage transformer:
Use too much current capacity and isolated voltage transformer does
not need to use stabilized power supply equipment.
Specification of RMS volt meter: Input resistance > 1 Mohm, Input
capacitance < 200 pF, Frequency range: 15 Hz – 1MHz . Refer
Figure 2. Isolated type volt -meter (FLUKE 8921A etc *1)
*1 Not use FLUKE 8920A that connected to protective earth by diode
# Leakage current of measurement instrument is less than 10μArms
when under test equipment AC plug is opened
# Set up the following condition and turn on the set. Applied voltage:
Nominal input voltage (Description on Nameplate)
# Measure the leakage current between one phase conductor and
neutral for terminal A and terminal B.
Read rms value, and then calculate to peak value PEAK VALUE =√2
RMS VALUE
Comply with the following requirement
Class II equipment (2-pin plug): for each terminal, the worst value
of measurementmust not exceed AC 350uA peak).
Note: including AC adaptor, AC adaptor/DC operated unit
combination
Figure 2 – Measuring network
for Leakage Current
1-7. How to Find a Good Earth Ground
1) A cold-water pipe is a guaranteed earth ground; the cover-plate
retaining screw on most AC outlet boxes is also at earth ground.
2) If the retaining screw is to be used as your earth ground, verify that it is
at ground by measuring the resistance between it and a cold-water pipe
with an ohmmeter.The reading should be zero ohms.
3) If a cold-water pipe is not accessible, connect a 60- to 100-watt troublelight (not a neon lamp) between the hot side of the receptacle and the
retaining screw. Try both slots, if necessary, to locate the hot side on the
line; the lamp should light at normal brilliance if the screw is at ground
potential (see Figure 3).
Figure 3. Checking for earth
ground.
1-8. Lead Free Information
The circuit boards used in these models have been processed using
Lead Free Solder. The boards are identified by the LF logo located
close to the board designation.
SDM-U27M90
Figure 4: LF Logo
Figure 5: LF logo on circuit board
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The servicing of these boards requires special precautions. It is
strongly recommended to use Lead Free Solder material in order to
guarantee optimal quality of new solder joints.
SAFETY NOTE
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TOOLS & EQUIPMENTS
1 LIST OF ITEMS TO BRING
(1) Screwdriver (e.g. #2 Phillips Screwdriver)
(2) Multimeter
(3) ESD WristStraps
(4) Service Manual (Unique)
(for remove & replace details)
2 OPTIONAL EQUIPMENT
(5) Screwdriver (e.g. #1 Phillips Screwdriver)
(6) Parts Tray for loose screws and small items
3 PREPARATION BEFORE REPAIRS
Before you begin, unplug the AC power plug from
the desk or wall outlet . Then simply place the
monitor faced-down on top of a thick blanket, on a
large/flat surface.
(1) (5) (2) (3)
(4) (6)
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