Steve Thompson wrote:
>>In more detail, please can you confirm which (if any) of the arcs has
>>either (a) holed the grid, (b) marked the cathode underneath, and/or (c)
>>burned the cathode?
>All of the marks with the brown circumference are on the cathode
>surface. There's heating discolouration on the grid above all but the
>smallest one, and the merest hint of distortion in the mesh above the
>really big spot top left. No holes in the mesh at all.
>
Thanks, Steve... very interesting. It confirms that arcs from anode to
grid do affect the cathode underneath as well.
Any idea how the tube went dud? Did it ever work, or might it have been
soft on arrival? Wonder how much HV?
--
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.com/g3sek
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