Jerrold 450 Non-Trimode Full Service Modification
by 4x of Group 42
Introduction
This information is good for Jerrold non-trimode 450 series boxes. An
external circuit using a 4081 or simalar AND gate, a 2n3906
transitor, two 10K resistors, a 100 ohm resistor, and a SPST switch.
Instructions
- Logic AND pin 6 of the 4096 and pin 10 of the 4011 using
a 4081 or simalar gate.
- Connect output of AND gate through a 10K resistor to the base of
a 2n3906 Transistor.
- Connect Emitter of 2n3906 to -5 volts (wire post 5) through a 100 ohm
resistor.
- Connect collector to -16 volts (wire post 3) through a 10K resistor.
- Cut the white wire going from wire post #10 to the metal can area at
the metal can area.
- Connect the white wire to the collector of the 2n3906 transistor
through the SPST switch.
- It might also be neccessary to short together wire posts 1 and 2
to defeat the addressability function.