I have a TLC 14001 NTSC monitor that has a vertical deflection problem. The horizontal deflection is working fine. The display starts 2/3 down the display and continues off the bottom of the display. I have probed B+, 14+ and 14-, and all appear solid. I found a STV9302A vertical deflection amplifier and I have probed the input signal. (Pin 1). I expected to find a ramp waveform, but instead I see something that looks like: ----____ ----____
--- | ---------------------- ------ | | | | | | | | |__-- | __---
I followed the input signal back to a TCL-A32V02-TO (8852CSNG5PF4) 64 pin ASIC. It appears to be manufactured by Toshiba due to the 885xC part number (I am guessing). I removed the resistor between the pin on the ASIC and the vertical deflection amp inp to isolate it. When I probed it, it still had roughly the same shape as above maybe without the bounce after the edges.
So questions... does anyone have any information on the above ASIC? Should the signal that drives the 9302 be a ramp? I assume it should be a 16msec period. If it does make a ramp, does it use an external cap to act as a integrator make the above signal? Does anyone know of a similar ASIC/TV that might give me clues? Am I even in the right area? So many questions.. so little info.
Thanks in advance, Greg