[SBE] Question about a toroid core --

[Mike Langner]

Thanks !  This may well be it !!  There is a second choke between this one
and the power source -- the second choke is a single winding of 8 turns on a
1 inch toroid with no coloration or markings of any kind -- ostensibly for
power supply decoupling, so having a broadband low-Q (relatively speaking)
where the toasted one is located makes perfect sense !!

Thanks again !!

Mike/
_______________

  -----Original Message-----
  From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org]On Behalf Of Glenn
Little WB4UIV
  Sent: Monday, December 08, 2008 9:47 PM
  To: sbe member discussion mail list
  Subject: Re: [SBE] Question about a toroid core --


  See:

  http://www.micrometals.com/materialchart.html

  This shows a orange color used to mark a mix 8 core. This core is for low
frequency for resonate operation.  For broadband operation it is listed for
10 MHz to 40 MHz. This may be your core as you are not looking for a high Q
in a broadband situation.

  You might measure a good coil and calculate the require core material to
get that number of turns for the inductance that you have measured.

  Hope this helps.

  73
  Glenn
  WB4UIV

  At 11:05 AM 12/8/2008, you wrote:

    Hello !

    I'm in the midst of repairing a 150 watts Silicon Valley Power
Amplifier, a filter-tuned unit that operates in the FM band.

    It has a "toasted" toroid.  The toroid is one inch in diameter, has (or
more correctly, had before it was badly overheated) orange paint along one
side, and is used as a bifilar-wound choke wired so that it looks to the two
FET's like windings of a push-pull autoformer.

    If I remove a good toroidial unit from another amplifier, the amp with
the "toasted" toroid works perfectly.

    Question:

    What's the toroid's makeup ?  I'm thinking as I dig into some more
research, that it's likely "43" material, but that's just a slightly
educated guess.

    The amplifier's manual's documentation provides no information about the
coils -- either the air-wound or the toroidial ones.

    May I please ask for suggestions for the toroid's core composition?

    Thanks !

    Mike/

    Mike Langner, CPBE
    Albuquerque, NM
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