5.5" Composite Mod

Written by Eli Krause

This mod will disable the RF input and replace it with composite. RF could optionally be retained if desired by using a DPDT switch to toggle between A/V inputs. Getting access to the bottom of the PCB requires multiple layers of disassembly and keeping track of several different types of screws.

1. First the original RF video source is disabled by cutting the signal coming from pin 16 of the IF IC LA7530N. On the Magnavox CG3920 lift one side of resistor R115. On the Emerson PC-6 lift one side of R110.

2. Connect the new external composite signal to TP02 on the CG3920, or TP01 on the PC-6, and connect composite ground to any chassis ground point. You can test with alligator clips before hardwiring it in.

3. Similarly to the video, the RF-originating audio signal coming from pin 3 of the IF IC LA7530N will be disabled. On the Magnavox CG3920, lift the side of R108 closer to LA7530N and connect the new external audio signal to the lifted side of that resistor. On the Emerson PC-6, lift the side of R103 closer to LA7530N and connect the new external audio signal to the lifted side of that resistor. Connect incoming audio ground to any chassis ground point.