[AMPS] TL-922 Filament Transformer Protection

[Ian White, G3SEK]

Rich Measures wrote:
>>Rich says:
>>
>>      > However, when R-sup fails on 15m, 20m, 40m or 80m, 
>>      >there is seemingly no way that enough fundamental potential could be 
>>      >developed across L-sup to damage R-sup.  
>>
>>If the
>>resistor has to be derated because the ambient is 80 deg C, then even the
>>lower dissipation on the lower bands may well be enough to 'cook' it.
>
>€  the R-sups in the 922 receive cool forced air and they are virtually 
>HF-shorted by silver straps.  Does it seem likely that lower-band RF 
>could damage these resistors?  

This brings us back to the old problem that we never know the condition
of the resistor (and/or tube) immediately before it failed. Was it still
like new, or had it already deteriorated way out of specification? Just
because the component finally failed on 80m, it doesn't mean that all
the damage was done on that band.

73 from Ian G3SEK          Editor, 'The VHF/UHF DX Book'
                          'In Practice' columnist for RadCom (RSGB)
                           http://www.ifwtech.demon.co.uk/g3sek

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