Color Monitor Bulletin No. : 97-C/M-E0001
Model : QB chassis / SC-428PT/PTL Bulletin Date : Jan. 9, 1997
Buyer : : All subsidiaries ECN # & Date : Jan. 4, 1997
Subject : QB CHASSIS, Corrective action for Q44 failure
Background : Plan (Establish) a countermeasure about the Q404's failure in horizontal
circuit of 14 inch color monitor.
¡à Symptom : No raster
Cause : For prevent the occurance of difference of horizontal/vertical off time
in suspend mode, (Q415 base current limit) resistance value is setted
to large value.
Due to this setting, when you change from suspend mode to normal
mode Q415's off time is delayed about 15 ms and so Q404 is failed
bacause abnormal pulse is generated at Q404's base which is
H.D.T drive TR.
Solution : Change Q415 base current limit resistance
