50th Anniversary CK722 Radio

BUILD YOUR OWN WORKING HISTORIC CK722 RADIO

 

PROJECT DETAILS

(Continued)

 

 

 

 

 

 

PROJECT DETAILS

(Continued)

 

The bottom scan shows the top of the CD case, with the CK722 radio insert installed inside the case this shows the condition before the holes are drilled in the case and the screw/knurled nut combinations are installed and the components of the radio are added. The top scan is a close-up of the method used to attach the CK722 into the circuit. The knurled nuts are hand tightened, and this method is used for both the CK722 transistor and the CK705 diode required for the radio. The three different case types of the CK722 are shown in the middle photo. The silver case is the most common and was used in the late 50s through to the mid 1960s this is the best performing CK722 type, most likely because transistor technology had improved considerably by this time. In my opinion, the blue-cased CK722 is the most interesting visually. This type also performs well. The black epoxy case was used only on the earliest CK722s, from 1953 through 1955/56. Many of these CK722s are no longer functional, probably because the epoxy case was not hermetically sealed, and moisture penetration has degraded the transistor junctions over time.

 

50th Anniversary CK722 Radio

Go To Page 5

 

 

 

 

 

50 YEARS of the CK722

A New Volume of Projects Featuring the Most Famous Transistor Ever Made

COPYRIGHT 2003 by Jack Ward. All Rights Reserved. http://www.ck722.com