Title: TelcoVISION KT1401 voltage question Post by: badbaud on July 03, 2011, 02:36:50 AM I have the manual and a monitor that won't come up. Did a cap job with no luck. All of the DC voltages coming out of the power supply check good. Still don't know why someone would short the collector to emitter of Q601 but the monitor power supply has good outputs so I didn't mess with it.
My problem is with IC501, the CD4070. It is getting good signal inputs but no outputs because the Vcc on pin 14 is not present. None of the schematics in the service manual show where this IC gets it's Vcc from. The other IC's on the board all show where they get their operating voltage from, the 29VDC or 110VDC is ran through a zener to get 12VDC. Right now this IC has no Vcc and I believe it is the reason why I have no high voltage... or does it have to have high voltage before 12VDC is generated from the FBT? Any help would be appreciated. |