[Amps] Alpha 76A metering changes

Jerry Kaidor jerry at tr2.com
Fri Jun 29 06:22:33 PDT 2012


> Like many amplifiers, the Alpha 76A (and variants), does not have a grid
> trip circuit.  Years ago I installed build a board that did a number of
> tasks in addition to a grid trip, including SWR trip, peak reading and a
> few
> other things.

*** I was looking at my Alpha 78 with an eye to adding circuitry.  The box
is pretty packed.  Where to put it?  On top of the power supply circuit
board ( the one that screws to the big electrolytics ) is the QSK T/R
board.  This is a smaller board that plugs into an edge card connector. 
The connector is hinged so you can swivel the T/R board up for access.

   To add circuitry in a neat and professional manner, I propose to make a
duplicate of the T/R board on a larger piece of stock.  Then I can add
whatever I want on the leftover copper.  The T/R board is not complex -
the
traces are wide and so are the spaces between them.  It is single sided,
and does not even have plated through holes.

   I have been making my own circuit boards with toner transfer.  I use
expressPCB software to design them, print them out on a laser printer, and
iron them onto the bare PC board stock.  I have done down to 25-grid
surface mount parts.

   With a double-sided area and surface mount parts, a *LOT* of circuitry
could be added to the expanded T/R board.  I am especially fond of
surface mount bypass capacitors.

                          - Jerry Kaidor ( jerry at tr2.com )






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