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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). Replace jumper wire JP104 with a 100
ohm ½ watt resistor. The resistor will act as a delay and improve the R,G,B
surge absorbers discharge effect. Replace the 300V spark gaps at each of the
Red, Green, and Blue cathodes of the CRT with 200V surge absorbers.
PARTS LIST:
ORIGINAL
Location No.
Part No.
NA
NA
JP104
NA
SGR1
4715-000106
SGB1
4715-000106
SGG1
4715-000106
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 8-1
SERVICE BULLETIN
PRODUCT: Computer Monitor
BULLETIN: MON 97-008
MODEL:
Description
NA
JP104
300V, Surge Absorber
300V, Surge Absorber
300V, Surge Absorber
CFG9637
NEW
Part No.
Description
0403-000366
ZD 7.5V
2001-000028
R-CF(S), 100 ohm, 1/2W
4715-000102
200V, Surge Absorber
4715-000102
200V, Surge Absorber
4715-000102
200V, Surge Absorber
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