09-04-2023, 09:38 PM
Hi Arran,
It happened to me twice, once with an old school 80, the other with a 5Y3. The one that all but caught fire was due to a filament to plate short on a 5Y3 which was a much stronger construction than an 80. This was a working post war Philco console radio that was about 25 years old at the time. I do run old 80s, especially globes in my Philco 20, Radiola 17, 60 and my GE S-22 (RCA R7A), but I have recapped these, performed the diode mod and added AGC fuses for slightly above the power rating.
The diode mod will not protect from a heater to cathode short on a 6X5. Yeah, that failure is a disaster that can be only protected by a fuse (or not, depending on the rating used). The 6X5 and its cousins are not prone to plate-filament shorts.
Yes, I did have 2 radios that had cooked power transformers when I received them. My RCA 5T7 (ca 1936) had a transformer that would heat up with no load. When i opened the transformer all the insulation paper was black. The other was a GE G53, ca 1938. (GE was building their own sets by then; it was not built by RCA and did not have the usual "This set designed to use RCA Radiotrons". There was a sticker advertising GE Metal tubes.) The tube complement was the same except that the GE used a 6K6 instead of a 6F6. The transformer in this set had actually caught fire.
It happened to me twice, once with an old school 80, the other with a 5Y3. The one that all but caught fire was due to a filament to plate short on a 5Y3 which was a much stronger construction than an 80. This was a working post war Philco console radio that was about 25 years old at the time. I do run old 80s, especially globes in my Philco 20, Radiola 17, 60 and my GE S-22 (RCA R7A), but I have recapped these, performed the diode mod and added AGC fuses for slightly above the power rating.
The diode mod will not protect from a heater to cathode short on a 6X5. Yeah, that failure is a disaster that can be only protected by a fuse (or not, depending on the rating used). The 6X5 and its cousins are not prone to plate-filament shorts.
Yes, I did have 2 radios that had cooked power transformers when I received them. My RCA 5T7 (ca 1936) had a transformer that would heat up with no load. When i opened the transformer all the insulation paper was black. The other was a GE G53, ca 1938. (GE was building their own sets by then; it was not built by RCA and did not have the usual "This set designed to use RCA Radiotrons". There was a sticker advertising GE Metal tubes.) The tube complement was the same except that the GE used a 6K6 instead of a 6F6. The transformer in this set had actually caught fire.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards,
MrFixr55
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