Panasonic NV VP32 VCR

I purchased a SD set top box and connected to the TV on AV3, all works OK.
When TV switched to TV mode can also watch the old channels.
I then connected the set top box to AVI1 IN on the VCR but can not see or hear any output on AV2 on the TV as this is the output that plays from my VCR.
I also tried the set top box to AV2 In on the VCR but still can not see or hear any output.

I would appreciate your advise.
kevsim