Programing The Vcr For 3 Digit Channel Recording.

We own 2 Panasonic PV-4660 VCR's both still work fine. One machine allows me to set a three digit channel from a Comcast Cable Box signal and the other only allows channels up to 99, we would like to be able to set 3digit channels on both machines but don't know how to change the setting on the one machine. This model VCR has a VCR Plus Gold feature which will send a signal to the cable box and change the channel automatically during the night when we want to record a second program from a different channel. The cable box is a Motorola INTERACTIVE DIGITAL COMMUNICATIONS decoder box.I have followed the reset procedure in the manual for this machine but nothing seems to work. Can you help?thank you, K Pohlschmidt