Introduction

Instructions

• Install lead from U16 pin 9 to a SPST switch, other lead to ground. This is the scamble/normal video switch. Open is scrambled, closed is Normal Video.
• Run a lead from U10 Pin 6 to a 20K resistor and then to pin 4 of J2 which is a source of 12 VDC. This will enable the audio section.
• Ground Pins 9 and 10 on U16 to enable the video.
• Cut the printed circuit at point x (see diagram) and solder a lead and a .01 cap to ground at this point. The lead goes to the center wiper of the 10K tuning pot, the other 2 ends of the tuning pot go to ground and +25 VDC. See diagram for location of the +25 VDC.

If the lower board is used, Pin 16 and 17 must be removed on J3 to enable the scramble/normal switch.

Different combinations of the A/B switch will probide full coverage of the cable channels 2-6, 7-13, 14-36 and so on.

You can also use the Tocom as a channel 3 unscrambler with a channel 3 output converter ahead of the Tocom. This allowes you to hard wire the switches into a working configuration and not have to mess with switching them for different channels. Alternativly you can build a simple descrambler that will replace this box compleatly.

Also if you are using surplus main boards and power supplies, make up a power coard to go between the power supply and J1 of the main board as per diagram.