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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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27th Dec 2019, 6:20 pm | #1 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
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Switched pots with the switch at the "wrong" end.
Does anyone know if these are still made?
I've got two receivers [a Hallicrafters S27 and a Stewart-Warner-built version of the Collins TCS-12] which use them as the RF-Gain control. The single-pole switch opens when the control is turned fully to the right - in this position it de-grounds the AGC line so the AGC works in the traditional way. Through the normal travel of the control the switch is closed so the AGC-line is shorted-to-ground - which is what you'd want if you're controlling the RF/IF-gain manually. |
27th Dec 2019, 7:11 pm | #2 |
Dekatron
Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 5,737
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Re: Switched pots with the switch at the "wrong" end.
Yes. I's one of six switch option offered by Blore Edwards on their '45' range. See:
https://www.blore-ed.com/series45potentiometers The diagrams showing the six switch option are at this link: https://3d099782-b028-40d1-9b5e-4378...13cdf7c89c.pdf I've highlighted the option you refer to in the (not very clear!) scan of the options below. (You can also have an SPST switch that is O/C throughout the rotation of the pot and only closes when the pot is fully clockwise). There are other option to consider when specifying a pot, such as 1/4"or 6mm shaft, do you need a flat on the shaft, if so, at what angle, do you want a metal or Delrin shaft? Maybe you're just asking out of curiosity, but if you do need a replacement, it's best to talk to Brett at Blore Edwards to make sure you order exactly what you need. Hope that helps.
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David. BVWS Member. G-QRP Club member 1339. |
27th Dec 2019, 9:28 pm | #3 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
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Re: Switched pots with the switch at the "wrong" end.
Ooh! Thanks! That looks precisely like what I need. Now to work out if the one on the TCS-12 is linear, log or inverse-log taper.
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