A little HELP!!

[aerostar]

Here is code, hex file and other files made by PBP3 , Microchip assembler, tested working with my NTSC source.

I used a second STV NTSC board as the video source (top board in picture) , connected that output to the input of the original board board (bottom board in picture), and it switches back and forth OK.

Top BNC is video input, bottom BNC is video output on the boards. Micros are 628a pics

With no input to the bottom board, you see the NTSC. and the No synchs message, with NTSC input from the top board, bottom BNC, NTSC. is overlayed on the incoming video, my top board board puts out NTSC VIDEO SOURCE.

Compiled (with help of friend) PBP 3.1.0.1, mplab 8.92 MCS version 5.00.5 and programmed with pickit 2 v2.61 programmer. this I think matches your software setup - your programmer unknown.