SB101 on 40 Fixed

[Stewart Lyon]

Hi Gang;
Last week I appealed for help on getting my SB101 to work on 40
meters-transmit.  The problem was that it wouldn't develop enough drive for
the 6146 finals. And only on 40.  It received great and transmitted great on
all bands except 40.  Several people posted some good suggestions for which
I thank them - it's nice when people will take the time to help someone else
with a problem.

And the fix was ... none of the above.

A valuable clue was provided by Allen - KJ6XH when he suggest that I take a
look at the postings of Joe Lutz in
http://www.tempe.gov/archives/archives/boatanchors.html.  There ( and at
/heath.html) Joe has placed all the Heath service bulletins he could get his
hands on.  And there in was! Heath bulletin no. SB-102-5 "Low 40 Meter
Output", Oct 29,1973 (in Joe's June'97 Heath posting).

What this bulletin described was a rearrangement of the grounding of the
switch PCBs for the grid and plate wafer switches and the RF driver board.
Apparently, in their zeal to isolate that section, Heath grounded everything
and created a ground loop that only affected 40 mtrs.  I rearranged to
ground wires according to the bulletin and now I get plenty of grid drive on
all bands.  RF sure does strange things.

Joe Lutz has provided an enormous service to Heathkit hams by his archiving
of these valuable service bulletins and preserving them for future use. I'm
sure Collins, Hallicrafters & other restorers wish they had available
similar insites to the factory engineers' thinking.  I know I would have
never come up with the solution to my problem without the help this bulletin
gave me.  And there's a lot of other good ideas in the other SBs.  Joe,
thanks a lot.  From my standpoint, your tremendous effort was much
appreciated. Too bad you couldn't find all the SBs.

Thanks to all and 73 -- Stu Lyon, W6CUX