|
I haven't reinstalled the original L42 coil yet. I did reinstall the original T115 quadrature transformer.
It seems possible the detector diode was always bad, but when first looking at that output way back when, I only scoped the grid of the 1st video amp, which gives a skeletal luma-like signal, even with a new diode. I should also have looked at the cathode of the video amp, where color information (including burst signal) appears. Perhaps the signal coming out of the video detector network wasn't as bad as I first assumed.
Since that time, I have also replaced dozens of resistors in the chrominance circuits, the video board, and the video IF board. Those replacements corrected a number of wrong voltages. It's tempting to look for a single "silver bullet" solution, but I suspect that the TV started out with a bunch of problems (maybe including a funky diode), which I'm still in the process of correcting.
Phil Nelson
|