Carl wrote:
>
>
>Ian, do you have any references to those diodes NOT protecting a
>SB-200/220 meter? I certainly dont and have seen many failed 1N400x
>diodes that saved the meter. Redesigining the Heath circuits is not an
>option to most users.
>
Granted - for those particular meters in that particular amplifier.
Carl and I are approaching the problem from two different directions. He
repairs many examples of the same models with the same faults, so he
builds up a wide database of experience. But my boards sell mostly to
individual constructors - every amp is different, and the only way I can
cover that wide range of unknown situations is to aim for the maximum
possible protection.
The "0.5V full scale" idea can do that. Bill's method using a series
resistor is the simplest, while mine will work with a wider range of
meters.
--
73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek/boards
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