[R-390] Break in function

[Roy Morgan]

At 06:39 PM 3/11/03 -0700, Kenneth wrote:
>The above radio is hooked to a Johnson Viking II through a TR relay.  It
>(the antenna relay) does the antenna switching and it has
>additional connects which I  use to operate the break in function on the
>390A. ...  My question
>concerns the break in relay in the 390A does it just disconnect
>the antenna, and mute the receiver.  Is the speaker muted as well?

Ken and others,

Some time ago I wrote a detailed description of the break-in function, with 
part numbers and such. I can't find it just now but here are the basics for 
the R-390A:

- The break-in relay coil is operated with 6.3 volts ac filament current by 
grounding a rear panel terminal, and carries about 40 ma ac when energized.
-  The relay will only operate as above if the BREAK IN switch is on the ON 
position.
-  When the relay is energized, it does the following:
    1) Grounds the common audio input to both audio preamp stages: line and 
local
    2) Operates the antenna relay to remove the antenna input connectors 
from the RF INPUT circuits (both Balanced and Unbalanced) and ground both 
antenna input connectors.



Notes:
  - The connections from the audio output tubes to the line or local audio 
outputs are not affected.
  - The entire R-390A is left fully operating.
  - No local oscillators or amplifiers are disabled.
  - No changes to the RF or Audio gain are made, except to ground the audio 
signal from the detector to the audio amplifiers.
  - The grounding of the antenna inputs depends on the condition of the 
antenna relay contacts and also the condition of the antenna relay supply 
rectifier and filter cap (there *is* a filter cap, right?)  Low relay 
voltage may cause high closed contact resistance.
  - The reduction in audio signal level toward zero depends on the 
condition of the break-in realy contacts and grounds in the audio module.
  - During "break-in" operation the whole receiver is capable of receiving, 
except for the grounded antenna input and the grounded audio.
  - The break-in relay and antenna relay are hopelessly too slow for real 
QSK operation.

Roy


- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
7130 Panorama Drive, Derwood MD 20855
Home: 301-330-8828 Work: Voice: 301-975-3254,  Fax: 301-948-6213
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