37-84 5y4 pin 1 to chassis - Printable Version

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+--- Thread: 37-84 5y4 pin 1 to chassis (/showthread.php?tid=15696)

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37-84 5y4 pin 1 to chassis - rickd - 11-16-2016

Nice 37-84 works fine after recapping/re-resistoring. Has a connection (apparently factory) from chassis to pin 1 of the 5Y4.
Disconnected for redoing the cap block it was hooked to. Left it disconnected and set seems to play fine.
Any idea why it was there?

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RE: 37-84 5y4 pin 1 to chassis - Dennis Craft - 12-19-2016

Hello Rick,
The NEW metal tubes were introduced around 1936 and sets designed to use these tubes grounded pin 1 of the socket, which was connected to the metal shield around the tube. In situations where RF signals are present, such as the RF amplifier or converter or IF amplifier, leaving this pin ungrounded can cause the set to oscillate or poor reception. I had someone bring me a Zenith set once with this issue. It was designed for the G suffix tubes with a tube shield and someone had put a metal tube in as a replacement. I think it was a 6K7. By grounding pin 1, the set performed wonderfully. As the 5Y4 is a rectifier, it's not likely that leaving this pin ungrounded will cause many issues.

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