1973 Zenith B&W Set - Good Audio, Plenty of Snow, No video through VHF

[LowHeadRoom]

First off,

Thank you for the great advice so far!

The screen is supposed to display video from a vintage game console. I was using NES Tetris and can get full audio from the console.

I have switched between channels 2, 3, and 4 and can get audio through those channels but nothing that even slightly resembles the Tetris game.

I have swept through the fine tuning, turning it left and right for a full sweep. No combination of channel selection and using the fine tuning brings up the Tetris game display.

I have also swept through the AGC control back and forth but do not get anything resembling the Tetris game.

Here are some videos to show how the TV is functioning. I am using the RF modulator this time instead of the NES. It has the same symptoms:

Contrast, fine tuning, vert hold etc:

https://photos.app.goo.gl/Sk8SwCkAQ4RTVSng7

AGC:

https://photos.app.goo.gl/vz4ZQT6KNu5iHCBH8

Snow:

https://photos.app.goo.gl/wtbxbau9DM8WFckZ7

THANKS AGAIN FOR ALL OF YOUR HELP!!

I am thinking it is a bad video detector diode as well.


Thank you,