It appears you have two problems. One is your power supply is passing full power voltage and current to your radio. Q4 the 2n3055 pass transistor is most likely shorted. I suggest replacing it with a more capable transistor that can handle more current. A 2N3772 is a good choice. Your final transistor in your radio is bad as well. Which one caused what is hard to say. If the power supply pass transistor passed too much current got too hot and broke down, then shorted causing 20 volts to appear at your radio it then fried your final power output transistor by making it put out more power and draw more current then it can handle. Or it could have happened this way: your CB radio had a bad match at its output like a shorted antenna or feedline or someone tweaked the final to make it output more power, and the result would be the final would draw too much current asking the power supply to supply more current which got the pass transistor to fail. Either way they both have failed. To prove this theory you can replace the pass transistor easily with a good heat sink grease and good soldering. To see if the radio has a problem, hook it up to a car battery. I bet they both have problems.

Sounds as though the regulator transistor/s have gone bad. Check these parts by taking them out of line(disconnect them from any wiring) and check for shotrs or opens with a transistor checker or VOM.
If I can be of any more help, please email me at [email protected]. "Original Radio Man" Ed