It all started one fine day last week when I noticed an add in our local paper saying 10 floor model radios for $30 each. I went to the persons house and purchased a RCA R-32 whale mouth and a Majestic 90. Both will need much work but are very viable sets. While visiting the owner showed me his great radio collection. He also had this Zenith chasis that another local repair shop had worked on. They said the transformer was weak and was overheating. I said I could look at it for him and he agreed. When I got the set home I did some initial testing and found that the 6X5 had a short from one of the plates to the cathode. The primary filter cap had also been snipped out of the circuit. I removed the 6X5 and plugged in the set and the filaments lit. Then I connected an external B+ supply and monitored current draw. The radio came to life. As I increased the B+ to normal value the volume started to decrease and distort. The audio coupling cap was biasing the 6F6 positively. I hung a temporary cap in place and the volume stabilized. After running the set for several hours the transformer remained at normal temperature. After talking to the owner and working out a radio repair for radio trade arrangement, I started recapping the radio. Recapping went fine and the radio worked ok except the antenna wire was connected to the tuning capacitor instead of the antenna connection terminal. The antenna connection terminal was non responsive. I found that the upper small input coil was open. On opening the antenna coil can I found the small coil wire were disintegrated. I was able to count the turns and direction and rewound it using hot melt glue and wax from one of the old capacitors. The rebuilt coil worked good. The IF and RF section were re-adjusted and the radio worked great except the low frequency end would cut out as I tuned the radio. I found a bead of metal on two sides of a plate of the RF section of the tuning capacitor. I tried to push it off the plates thinking it was a solder bead but it wouldn't budge. Out came the dremmel and after a tense moment the beads were gone. After running the set the volume would get noisy. The 6F5 was the culprit. When the pushbutton tuner was tried it did not work. The switch plates were black with tarnish. I used some metal polish on a cue tip to get the silver back. Then I totally cleaned the contacts and sealed them with silicone spray also applied with a cue tip. The radio is lively, the transformer is normal, and I am looking forward to the next challenge.
MRO