Testing 6146B/8298A with a 177/b

[mike bryce]

marco....

tube testers are great if you want to find a really dead tube in the set.
The best way is by subing  in a new pair ( i.e. another set new or used) and
see what happens.

now, dig out the vom and check for +800 on the plate caps
then dig around the cathode resistors. make sure they are within specs. Too
high and the tubes won't conduct.

check the bias. it should be about 60 ma in tx with no drive. Too much bias
and the tubes will be cutoff

check for continuity in the RF chokes in and around the cathodes.

and of course, try subing out the driver. You got to have enough bang going
into get more bang going out.

--
Mike Bryce WB8VGE
SunLight Energy Systems
"Electricity at the speed of light"

> From: Marco Ciocca <marco at PA.UKY.EDU>
> Reply-To: Marco Ciocca <marco at PA.UKY.EDU>
> Date: Mon, 7 Aug 2000 11:09:30 -0400
> To: HEATH at LISTSERV.TEMPE.GOV
> Subject: Testing 6146B/8298A with a 177/b
>
> 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).
> Anybody can help?
>
> Thanks,
>
> Marco (one of the new almost codeless extra)
> Marco Ciocca                            KF4URS
> Dept. of Physics and Astronomy          phyciocc at acs.eku.edu
> Eastern Kentucky University             Office: (606) 622-6172
> Richmond, KY 40475                      Fax: (606) 622-1399
>
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