so that I can assemble it up myself.

 

Check out Cool Tech.
They have the complete setup ready to install.

 

Thanks!

But what I meant is a set of components, like mainboard, chips, diodes ...
and a diagram for me to build up a CB radio from scratch

 

Wow....a homebrewer. You should look into HAM radio to get the most from your efforts....

 

Heathkit is unfortunately a thing of the past.

I don't know of anyone that sells a kit of that type. Maybe you could find the diagrams from an old kit, but a project box, and take it from there...

 

Yes, it's hard to say if you could actually find an actual kit anymore, but you should be able to find articles or books that would tell you all you need to put a radio together. Although it's pretty much a lost art, I'm sure some die hard HAM radio enthusiasts are still doing it. I would go to sites like the ARRL, Eham, QRZ etc... to see what you can find. If you do decide to take that on, good luck and please keep us advised....