[GreenKeys] Dovetron help

[John Lawson]

  Season's Greetz de John, KB6SCO

  After procrastinating for months, today I pulled the Model 19 out from
the wall, took it down to major subassemblies, and cleaned/lubed/fussed
until it now seems to be printing with few errors...  and I have a couple
of other little tweaks to make, it should be ready for prime-time. Next
task is to bring up the whole table as a unit.

  I have a Dovetron, MPC1000 CR, with the TSR-200D unit installed, and a
'regen' switch hogged into the front panel as well.

  In order to test, I am feeding it with the 'pure' RTTY output of TrueTTY
in transmit mode.  The LED display on the Dovetron looks like I would
expect it to - Mark and Space crossed equally, four LEDs in the corners
lit, nothing in the center.

  I am using the 'two-way' loop supply jack, and in fact 60ma is flowing
in the selmag circuit, verified by meter.

  My Problem is: I can't seem to make the loop actually key, no matter
what I do... it is always on, the 'loop' led stays lit, steady current
flows.  I have the cover off the unit - nothing seems obviously cooked or
missing.  Since I have neither manual or schematic, I am relying on
inspection to tell me what's doing what in there.  I notice that there are
two transistors mounted in sockets, 'Q6' and Q7'... near the middle of the
board next to the power supply. Are these in the loop keying circuit?

  Since this is the first time I've tried to use the Dovetron since I got
it some years back, I plead most wretched ignorance concerning same.

  If anyone can point me in the direction of schematics and/or a user
manual, that would be most appreciated - what's likely is I'm sure to have
missed something in my hook-up or set-up.

  Any info is much appreciated - my goal is be QRV on 20 with the Model
19, Swan Astro 102BX, and Dovetron as a mid-vintage RTTY station.


   Cheers

John