11-12-2024, 06:04 PM
Hi Folks,
If you are talking about Part #7, this is the cap that capacitively grounds the physical chassis to B- and is important. It should be 0.2uF and the coil portion is likely not urgent, just good engineering on Philco's part.
The likely proper values should be 0.2UF, similar to other Transitones, like the 42PT94.
Some people call this the "Death Cap" because of the following:
For some reason (possibly to reduce hum), the power switch is in the B- and filament return leg of the power line. This is the point where the cap in question connects B- to the chassis for RF coupling of the tuning cap, shields, etc., making this a "warm chassis" set. This is as opposed to a hard wire connection between chassis and this point making this a "hot chassis" set. The problem is that if this leg is connected to the neutral pin of the power cord, the chassis is at ground potential with the power ON, making it "safe". However, with the power switch off, the low cold resistance of the tube filaments make the chassis "hot", even though the cap. The cap will limit current (warm chassis) unless it shorts, then there is no limiting, making the thing a death trap.
So, the issue is that with the way the set is built, that the chassis will be hot depending on the position of the power switch and the polarity of the plug. With the plug in one direction, the chassis will be at ground potential when the switch is on but hot with the switch off. With the polarity of the power cord reversed, the chassis will be at ground potential with the switch off, but hot with the switch on.
Several restoration sites recommend moving the switch to the "hot" side (Input to rectifier and rectifier end of filament string) and using a polarized cord to prevent this condition.
If you are talking about Part #7, this is the cap that capacitively grounds the physical chassis to B- and is important. It should be 0.2uF and the coil portion is likely not urgent, just good engineering on Philco's part.
The likely proper values should be 0.2UF, similar to other Transitones, like the 42PT94.
Some people call this the "Death Cap" because of the following:
For some reason (possibly to reduce hum), the power switch is in the B- and filament return leg of the power line. This is the point where the cap in question connects B- to the chassis for RF coupling of the tuning cap, shields, etc., making this a "warm chassis" set. This is as opposed to a hard wire connection between chassis and this point making this a "hot chassis" set. The problem is that if this leg is connected to the neutral pin of the power cord, the chassis is at ground potential with the power ON, making it "safe". However, with the power switch off, the low cold resistance of the tube filaments make the chassis "hot", even though the cap. The cap will limit current (warm chassis) unless it shorts, then there is no limiting, making the thing a death trap.
So, the issue is that with the way the set is built, that the chassis will be hot depending on the position of the power switch and the polarity of the plug. With the plug in one direction, the chassis will be at ground potential when the switch is on but hot with the switch off. With the polarity of the power cord reversed, the chassis will be at ground potential with the switch off, but hot with the switch on.
Several restoration sites recommend moving the switch to the "hot" side (Input to rectifier and rectifier end of filament string) and using a polarized cord to prevent this condition.
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis
Best Regards,
MrFixr55
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