Hi CJ
Jack Sondermeyer was my RCA man @ that time and we had many talks about this test. Jack later left RCA and went to Peavey. I told Jack that in LA we seperated the men form the boy. The die bonding has air bubbles and Isb problems created hot spots burned up the devices.
Don't replace this part with a new 2N3055 as most of them are Epi base types and Ft will cause stability problems.
The output power is about 80-90 Watts and not 150 Watts. Back then marketing was very liberal with specs. I have many stories just like JR has.
Duke