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Old June 14th 07, 12:04 PM posted to alt.binaries.pictures.radio
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Default 500K pot for Bosch 28

I know I'm probably looking for unobtanium, but maybe the King of Controls
has something to replace this with?

It's SUPPOSED to be a 500K volume control pot for a Bosch 28, but it reads
only 165K, and loads the input stage down quite a bit (I subbed in a 250K
composition pot and the performance improved markedly).

Also, this pot is a wirewound, which does not seem right considering it's
across a tuned circuit in the first stage. It seems that it would change the
inductance in the circuit.

--
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Just say NO to HD/IBOC!




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Old June 14th 07, 10:04 PM posted to alt.binaries.pictures.radio
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Default 500K pot for Bosch 28

Brenda Ann wrote:
I know I'm probably looking for unobtanium, but maybe the King of Controls
has something to replace this with?

It's SUPPOSED to be a 500K volume control pot for a Bosch 28, but it reads
only 165K, and loads the input stage down quite a bit (I subbed in a 250K
composition pot and the performance improved markedly).

Also, this pot is a wirewound, which does not seem right considering it's
across a tuned circuit in the first stage. It seems that it would change the
inductance in the circuit.


What is the voltage drop on this pot? You may be able to use a 1 watt
carbon pot instead of the ww as 500K is not very common.
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Old June 14th 07, 10:33 PM posted to alt.binaries.pictures.radio
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Default 500K pot for Bosch 28

Lou D wrote:

Brenda Ann wrote:


Also, this pot is a wirewound, which does not seem right considering
it's across a tuned circuit in the first stage. It seems that it would
change the inductance in the circuit.


The point in the circuit it's in - it doesn't matter - as it's intended
to "shunt" signal anyway (as you noted - it's the volume control - and
it does it's job pretty well).

then Lou D wrote:

What is the voltage drop on this pot? You may be able to use a 1 watt
carbon pot instead of the ww as 500K is not very common.


Ain't none to speak of - the pot is antenna to ground - with the wiper
"picking off" signal to the grid of the 1st RF -- and obvisouly
providing ground return for the grid. So yes, a carbon 500K would
probably work - but - an original would be nicer.

Brenda- remember - the Eveready (National Carbon) models 1, 2, 3, 20 &
21 are the same chassis - so would have that pot as well... just another
place to look.

best regards...
--
randy guttery

A Tender Tale - a page dedicated to those Ships and Crews
so vital to the United States Silent Service:
http://tendertale.com
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Old June 16th 07, 01:30 AM posted to alt.binaries.pictures.radio
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Default 500K pot for Bosch 28


"Brenda Ann" wrote in message
...
Also, this pot is a wirewound, which does not seem right considering it's
across a tuned circuit in the first stage. It seems that it would change
the inductance in the circuit.

--
Say no to institutionalized interference.
Just say NO to HD/IBOC!

Hi Brenda

It is such a low loaded Q that the inductance has no affect.

Pete


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