[ARC5] More on the BC-1206

[Jack Antonio]

The main problem I ran into in getting my BC-1206-C running was
with shorted mica compression trimmers in the IF cans.

Had to remove the IF cans, uncompress the trimmers and gently blow
out the crud.  I have heard of metal migration in mica caps,
(such as the mica capacitors in Hallicrafters IF cans)
so I'm assuming this is what happened here.  Also, the tabs on the
loktal tube sockets were very prone to breaking off with
only a very minimal amount of movement, unsoldering
was a painstaking process.

 >On 2/7/2013 9:45 AM, Robert Eleazer wrote:

 > These were mostly single seat fighter aircraft, so there
  was only one set of headphones to drive.  I don't know if
  the 1206 got any audio assist from the 522 audio.

One of the AN/ARC-3 manuals (AN 16-30ARC3-3 rev 13 June 1949),
describes the interconnection of either a BC-1206 or MN-26. The
audio is connected to pin 14 ("Audio input(aux)") of the R-77 receiver.

The manual says there is to be a placard to state the VHF set must be
on to use the receiver. It also states that in the event
of failure of the VHF radio, to plug the headset directly into
the receiver.

I have other ARC-3 manuals that do not mention the use of the aux
audio input, and it appears that an external range or compass receiver
is directly connected to the headset line, essentially in parallel with
the VHF radio. (This is all referring to fighter or single place 
installations.)


I'd like to see documentation showing the interconnection of a -1206
to an SCR-522, to add to my files.

Jack Antonio WA7DIA/4