VIC-20 video output improvement

[Papalapa]

Well, after half a year with the components in the drawer today I have spent the day in modifying the video output of the VIC-20. Until now I used composite video but it was really bad in my VIC-20 there were even colors that sometimes were not displayed and screens where you could not even read the text.

The process is not complicated at all, just replace two components and cut two PCB tracks. Obviously the connection cable to the TV / monitor must also be modified due to the pin change. The components to be replaced are inside the cage where the video signal is generated. They are marked with a red circle in the picture.
 

Two tracks at the bottom must also be cut and a cable soldered.


 

Without the modification, pins 4 and 5 of the DIN connector carry the same signal (composite video), but after the modification pin 4 carries the luminance (Y) and pin 5 the chrominance (C), so the pins of the DIN connector they must be changed and a mini-DIN (S-Video) connector mounted in the other side of the cable to be able to connect to an S-Video input on the TV/monitor. Audio cable remains the same (RCA connector).

Once the modification has been made I also replaced all the electrolytic capacitors of the board and set a heatsink to three integrated circuits. The change has been brutal considering the terrible video quality it had before.

Before (composite)

After (Y/C)

 

 

 

[eightbit]

The S-Video mod has been public knowledge for many years:

 

http://sleepingelephant.com/denial/wiki/index.php?title=S-Video_output

 

That tutorial actually tells you that components need to be replaced with what.

[R.Cade]

Very nice improvement... I need to mod mine.

Edited March 30, 2020 by R.Cade