If I was desperate, I could send it down to my Uncle in Waynesboro VA and work out some kind of deal with him, but usually most people who worked on CB radios either died or retired because there is no money in it.
With electronic equipment being disposable, you just can't get someone to do $100 work on a $25 CB radio.
I am a tube man myself and just found the mother load of all tubes in the garage of my grandparents garage yesterday.
A lot of them says Knight Kit right on the box. Others are for Regency and Browning CB radios'.
Unfortunately, CB radios' has gone the route of the Dodo bird.
With Cell phones - where you can call anybody anytime for free and you don't have to share a channel with everyone for 1,000 miles, there is no reason for CB radio's except for use while driving down the road if you were worried if there was any smokies in the area that might pinch you for going too fast. Talking to truckers allows you to find out what is ahead and what is going on - if you are stuck in a traffic jam.
But other then that, the people with the high power rigs and side band ruined it for everyone else.
The Border Blasters down in Texas that are so loud that they transmit for 1,000's of miles and you can't get a word in edgewise.