Cobra 29 ltd classic is missing channels

I did a full alignment by the book and everything worked perfectly on all channels. I put it back together and gave it one last test for my stamp of approval but some of the channels have no carrier or modulation while others are loud and proud. I did most of my alignment on channel 19 and that is one of the channels not working. A few are upper channels and a few are lower channels. I'm just looking for advice on where to start before I start digging into it tomorrow. If I get no help then I'll probably start at ic3.

 

Ok thanks y'all. I'll check tomorrow and post what I figure out.

 

All voltages and frequencies checked out fine. I sprayed contact cleaner in the channel selector and noticed a wiggle. When I wiggled it just right it started transmitting on all channels. I found out that the ribbon wires came loose on the switch end from years of a wiggly channel selector. I'm going to reattach the ribbon and that should work.....I hope. Thanks everyone.