Advertisement
Quick Links
SUBJECT: CRT Substitution
BACKGROUND: Samsung is manufacturing the CMB5477L with three different
manufacturer's CRTs. Each type of CRT has parts that differ in
the heater, brightness, and the deflection circuits.
SOLUTION: The parts that differ from each other are listed in the parts list
below.
PARTS LIST: See the back of this cover page.
Disclaimer: This information is provided "as is" without warranty of any kind
either expressed or implied, including, but not limited to, the implied
warranties of merchantability and fitness for a particular purpose.
REV 10-1
SERVICE BULLETIN
PRODUCT: Computer Monitor
BULLETIN: Monitor 95-004
MODEL: CMB5477L
Advertisement
Related Manuals for Samsung CMB5477L
Summary of Contents for Samsung CMB5477L
- Page 1 BULLETIN: Monitor 95-004 MODEL: CMB5477L SUBJECT: CRT Substitution BACKGROUND: Samsung is manufacturing the CMB5477L with three different manufacturer’s CRTs. Each type of CRT has parts that differ in the heater, brightness, and the deflection circuits. SOLUTION: The parts that differ from each other are listed in the parts list below.
- Page 2 Location No. Phillips CRT Toshiba CRT SDD CRT TYPE : M36EDR320X TYPE : M36KUT23XX01 TYPE : M36KUK35X02 (CODE : 897-250089AA) (CODE : 897-250192AA) (CODE : 897-250134AA) R209 R-CAR, 10K, 1/6W R-CAR, 15K, 1/6W R-CAR, 15K, 1/6W (CODE : 911-151007YA) (CODE : 911-151507AA) (CODE : 911-151507AA) R463 R-CAR, 15K, 1/6W...
-
Page 3: Service Bulletin
SERVICE BULLETIN PRODUCT: Computer Monitor BULLETIN: Monitor 95-005 MODEL: Samtron SC-428PS SUBJECT: Vertical Deflection Circuit Improvement BACKGROUND: The Samtron 14 inch computer monitor SC-428PS has no vertical deflection after power up due to IC301 (TDA4866) and R301 failing. The problem is likely to occur with the serial number range of A9524002821 to A9538025160. - Page 4 Mounting Procedure - Add a ground lug to point A and point D as in the figure shown below. Take the 200mm wires and route them through the holes labeled E and F in the main pcb as in the diagram below. The holes are located next to the IC301 heatsink.
-
Page 5: Parts List
SERVICE BULLETIN PRODUCT: Computer Monitor BULLETIN: Monitor 95-006 MODEL: Samtron SC-428PS SUBJECT: Vertical Circuit Modification BACKGROUND: The vertical output IC301 has been changed from a TDA4866 to a TDA8351. The circuit change was made with serial numbers higher than A95025160. The circuit change was made due to the failure of IC301 in some cases during power up. - Page 6 SERVICE BULLETIN PRODUCT: COMPUTER MONITOR BULLETIN: MONITOR 95-007 MODEL: CQB4147 SUBJECT: No Raster BACKGROUND:There is a delay in the 12V/DC operation. Due to the delay the 166V/DC line operates first when power is first applied to the monitor. This will affect the horizontal circuit and cause a surge, which in turn will cause Q403 and Q408 to short.
- Page 7 SERVICE BULLETIN PRODUCT: COMPUTER MONITOR BULLETIN: MONITOR 95-008 MODEL: SAMTRON SC-428PT/L SUBJECT: No Raster BACKGROUND:There is a delay in the 12V/DC operation. Due to the delay the 166V/DC line operates first when power is first applied to the monitor. This will affect the horizontal circuit and cause a surge, which in turn will cause Q403 and Q408 to short.
- Page 8 SERVICE BULLETIN PRODUCT: Computer Monitor BULLETIN: MON 97-001 MODEL: CQB4147 SUBJECT: Reduce Q404 Failure Rate Causing No Raster BACKGROUND: Q404 fails when the monitor changes from the DPMS Suspend mode back to Normal operation. Q415 is designed, in the circuit, to cut off horizontal drive to the base of Q404.
- Page 9 SERVICE BULLETIN PRODUCT: Computer Monitor BULLETIN: MON 97-002 MODEL: CMH7379L SUBJECT: To prevent whistling sound from occurring. BACKGROUND: A whistling sound is created from harmonic noise generated between T402, L402, and the main PCB near the Flyback Transformer. SOLUTION: Add a piece of rubber to insulate the main PCB solder side from the bottom metal shield.
- Page 10 SERVICE BULLETIN PRODUCT: Computer Monitor BULLETIN: MON 97-003 MODEL: CQB4147 SUBJECT: Improve the Horizontal Output Transistor Quality BACKGROUND: The horizontal output for the CQB4147 has been changed as of May 1, 1997. The BU2508DF, which had been used prior to this date, has been failing intermittently due to a current surge from the 166 volt B+ line.
- Page 11 SERVICE BULLETIN PRODUCT: Computer Monitor BULLETIN: MON 97-004 MODEL: CFX1577L SUBJECT: Vertical Positioning Shifted Off Center BACKGROUND: Q302 and R327 fail in the vertical positioning circuit. The failure is caused by a current surge during power up and from the monitor recovering from an extended period in the DPMS Suspend mode.
- Page 12 SERVICE BULLETIN PRODUCT: Computer Monitor BULLETIN: MON 97-005 MODEL: CMH7379L SUBJECT: Q407 Failure Causing No Raster or Small Horizontal Size BACKGROUND: Q407 fails due to a transient pulse and current when mode switching from DOS to Windows. This occurs with a Matrox video card installed in the computer.
- Page 13 Figure 1 Top View of the Main Board...
- Page 14 Figure 2 Bottom View of the Main Board...
- Page 15 Figure 3 Snubbing Circuits...
- Page 16 MODEL: CMB5477L SUBJECT: Flyback Transformer Revisions BACKGROUND: Samsung instituted new revision flyback transformers as of October 24, 1996. The new flyback transformer will prevent intermittent no raster conditions. The revised flyback transformers that have been applied to the latest production runs will have resistance values changed in the x-ray protection and the high voltage adjustment circuits.
- Page 17 SERVICE BULLETIN PRODUCT: Computer Monitor BULLETIN: MON 97-008 MODEL: CFG9637 SUBJECT: Video Pre-amp (LM1205) Failure Causing No OSD BACKGROUND: The OSD blanking input stage of IC101 (LM1205) shorts to the Vcc input stage due to CRT discharging and surge current. SOLUTION: Add a 7.5V zenor diode between pin 13 of IC101 and ground (cathode to pin 13 and anode to ground).
- Page 18 SERVICE BULLETIN PRODUCT: Computer Monitor BULLETIN: MON 97-009 MODEL: CMB5477L SUBJECT: Video Pre-amp IC101 (LM1207) Failure BACKGROUND: IC101 becomes damaged from arcing within the CRT during electronic discharge. SOLUTION: Add a 300V spark gap in between the G1 grid of the CRT and ground.
- Page 19 SERVICE BULLETIN PRODUCT: Computer Monitor BULLETIN: MON 97-010 MODEL: CQA4147, CQB4147 SUBJECT: No Raster BACKGROUND: D618, which is the rectifier diode for the 166V line, burns due to a reverse peak voltage that occurs when power is turned off. SOLUTION: A snubbing capacitor must be added in parallel with D618 in order to prevent this from occurring.