Re: Tek 454 channel B drift/ nuvistor characteristics


 

--- Im TekScopes@e..., msfix56@y... schrieb:
Hello All,

It was suggested that perhaps the nuvistors in the B channel were
the
cause of the drift. This does seem to be the case. In an attempt to
prove that case I swapped the tubes out and the drift changed
channels. I have tested the nuvistors in the scope and several of
them test weak including the front end of the channel B preamp
which
if you watch the tube test meter drifts up from about 3000 uMhos to
about 7600 uMhos before dropping off sporadically.
Have you tried to clean the connector pins of the Nuv?
Maybe the heater has a bad contact that could make unstable and
weak conditions.

The other tubes in
the scope vary from 10000 uMhos to 11500 uMhos. My question is that
The 8393 is exactly equal to a 7586 exept the heater voltage (13.5V)


Jorgen
dj0ud

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