Composite video output for the Atari 2600 Jr
Hello. As you know, 80's game consoles are mostly connected to the television via an antenna input. Inside the console was an RF modulator that turned the video signal into something similar to that received through an on-air antenna. Some consoles also had a switch that allows changing the modulation frequency and, accordingly, the television channel. The quality of the picture through this connection leaves much to be desired. In one of my Atari 2600 Jr, the RF modulator worked so disgustingly that I decided to try to remake the console under the standard composite video output.
In the internet there are many options for implementing composite AV output, based on such a scheme from here , but collecting it as it is, I found out that it was a disaster with colors, I began to pick up resistance and I found a second interesting point, in some games the colors became better, and in some - worse.
It was decided to replace the usual trimmer resistors, as a result, the scheme turned out to be this:
Connection:
4 trimmers and capacitors are soldered on the circuit board. Trimmers selected in such a size that it was possible to get to them through the bars in the console cover.
In a protective screen, he bent one of the plates to remove the wires from under it. The existing RCA-connector used for audio output, an additional set for video output.
A board with trimmers secured with hot melt glue. Through the holes in the lattice there is access to them, the step coincided successfully:
Under the second connector, an additional hole had to be made in the rear wall of the case.
Results:
Popeye - RF Out
Popeye - AV Out
Pool Position - RF Out
Pool Position - AV Out
Trimmers allow you to adjust colors for a specific the game, the result justified the time spent, in my humble opinion.
In the internet there are many options for implementing composite AV output, based on such a scheme from here , but collecting it as it is, I found out that it was a disaster with colors, I began to pick up resistance and I found a second interesting point, in some games the colors became better, and in some - worse.
It was decided to replace the usual trimmer resistors, as a result, the scheme turned out to be this:
Connection:
4 trimmers and capacitors are soldered on the circuit board. Trimmers selected in such a size that it was possible to get to them through the bars in the console cover.
In a protective screen, he bent one of the plates to remove the wires from under it. The existing RCA-connector used for audio output, an additional set for video output.
A board with trimmers secured with hot melt glue. Through the holes in the lattice there is access to them, the step coincided successfully:
Under the second connector, an additional hole had to be made in the rear wall of the case.
Results:
Popeye - RF Out
Popeye - AV Out
Pool Position - RF Out
Pool Position - AV Out
Trimmers allow you to adjust colors for a specific the game, the result justified the time spent, in my humble opinion.