Hi Gary.
Sorry about my earlier post. I am unfamiliar with that amp and I
presumed it was running tetrode/s. By your follow up, it is apparent
that we are talking 3-500Z. Therefore my comments were probably not applicable.
Like you say, both tubes letting go, in the same way, at the same
time, could be considered unusual.
I believe all current production 3-500Z tubes, apart from Amperex,
are made in China so it won't matter much which sort you buy. Like so
many other things, its just badge engineering.
73, Alek
VK6APK
At 07:35 AM 10/06/2010, Gary Smith wrote:
>Hi to the group:
>
>Finally got around to taking off the cover (excess of twenty screws)
>removed both tubes from sockets and switched the amp on. No plate
>current draw. Good. Was suggested by TenTec to insert tubes one at
>a time and check plate current.
>
> Did that, plate current draw with either tube in place is 175 ma or so.
>
>Is there any way to check (with ohmmeter) for internal
>shorts? Which pin to what particular pin?
>
>I `spose anything is possible but both tubes going bad at same time?
>
>When checking the tubes, had the HV on for maybe no more than 30
>seconds or so, aluminum heat dissipaters on the tube(s) was
>extremely hot to the touch.
>
>Fwiw, tubes are RF products house brand. If I need new ones, any
>difference form RF house and Taylor's?
>
>looking of some ideas on this one (some more),
>
>73, Gary...wa6fgi
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