Testing 6146B/8298A with a 177/b

Jim Strohm jstrohm at TEXAS.NET
Tue Aug 1 11:39:38 EDT 2000

Marco thus spake:

>I have been fighting with a SB-401 heathkit transmitter, and I have come to
>the conclusion that the finals (6146B/8298A) are probably defunct.  I
>tested them with a simple emission tester and, although barely, they pass
>as "good".  I 'd like to use my transonductance tester, however, for a more
>reliable test.  Problem is I don't have the settings for these tubes.  Nor
>does the extremely detailed collection of test setting prepared by Nolan
>Lee (http://www.acadiacom.net/nlee/i177_index.html).

The late, lamented magazine Ham Radio published plans for a very simple
6146 tester that gave a reasonably good indication of transconductance
(though not a calibrated one) that was good enough to make matched pairs.
If you or anybody on the list would like, I could put a copy out on the web.

IIRC, it took only a transformer, a resistor, a capacitor, a milliammeter,
a switch and a socket.

Lemme know...

Jim  N6OTQ

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