[R-390] T4XB and R390A

Thu Aug 8 20:57:11 EDT 2013

YMMV.............but I've had some issues with using the muting relay to
open the RF gain terminals on the back of the R-390/A's. So for a while I'm
just using the relay to ground the muting contact. 

Two of my R-390/A's burned a little spot on the RF gain pot. I'd run the AGC
on auto and RF gain set at 10. Don't know if opening the RF gain terminals &
grounding the mute contact was the cause??????

Gonna try just grounding the muting contact for a year or
so.........................

Craig,
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-----Original Message-----
From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
On Behalf Of Steve Toth
Sent: Thursday, August 08, 2013 4:01 PM
To: Roy Morgan
Cc: r-390 at mailman.qth.net
Subject: Re: [R-390] T4XB and R390A

I just re-read the first sentence of my email - Correction required:

The T4XB send a GROUND on the MUTE line during receive - this is exactly
opposite of what the R390A requires on terminal 9 of TB103 during receive,
which is an OPEN.

So, Craig and the guys who described using a relay are correct.  An outboard
relay is required to get the operation of the T4XB and the R390A in synch.
if you want to use the MUTE line for actuation.

Off to find a junk box relay.....

-- Steve 
"There is always A way!"........anonymous

________________________________
 From: Steve Toth <stoth47 at yahoo.com>
To: Roy Morgan <k1lky68 at gmail.com> 
Cc: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net> 
Sent: Thursday, August 8, 2013 1:09 PM
Subject: Re: [R-390] T4XB and R390A

Roy
Nice try on the T4XB request! ; - )  But, if you don't ask, they can't say
"yes", right?

Found the answer:

The Drake T4XB has an RCA type RCVR MUTE jack on the back panel.  The center
conductor of this cable provides a short circuit to ground on receive and an
open circuit on transmit.

I looked through the functional descriptions in the R390A technical manual
the other night as well as the Y2Kr3 and was a little confused, hence the
query.  I just dug the tech manual back out and started to re-read the
section on the antenna circuit after I read your email.

The long answer:  All that's needed to use the R390A in conjunction with the
T4XB, or any transmitter for that matter, is the application of a ground to
terminal 9 of TB103 on the back of the R390A during transmit with the
"break-In" switch in the "on" position.  The ground from the mute jack on
the T4XB transmitter energizes relay K601 in the R390A which provides a
ground connection for CR102 which energizes relays K101A and B.  When K101A
& B are energized, all antenna input terminals are disconnected from the rf
transformers and are grounded.

The short answer: Connect the center conductor of the "mute" cable from the
Drake T4XB to terminal 9 of TB103.  Turn the Break-in switch to "on". 
Whenever the T4Xb is keyed, the R390A will mute.

The Standby switch also provides a ground to relay K601 when the mode switch
is placed in the "standby" position to provide the same function without a
hook up to a transmitter.

-- Steve 
"There is always A way!"........anonymous

________________________________
 From: Roy Morgan <k1lky68 at gmail.com>
To: Steve Toth <stoth47 at yahoo.com> 
Cc: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net> 
Sent: Thursday, August 8, 2013 12:34 PM
Subject: Re: [R-390] T4XB and R390A

On Aug 8, 2013, at 12:54 PM, Steve Toth <stoth47 at yahoo.com> wrote:

>  
> I'm looking at running my Drake T4XB and R390A as separates using the
antenna cable and mute cable from the T4XB connected to the R390A.
>  
> I'm sure somebody on the list has done this.  What needs to be done to get
this to work?  a separate mute relay for the R390A?  I believe the mute
signal my R4C requires from the T4XB (a ground, if I am correct) is
different than what the R390A requires.

Steve and others,

The mute line on the R-390A operates a 6.3 volt AC relay that does these two
things:
- grounds the audio signal at the input to the first audio amp in the audio
deck (before it is split to local and line amps)
- operates (or DE-operates?) the antenna relay to ground the antenna
connection to
 the RF input coil in use,  and open the connection to the antenna jack.

NOTES:  
- the mute terminal at the back of the R-390A will only operate properly if
the FUNCTION switch is in the "standby" mode as I remember.
- The rear terminal operates the 6.3 volt AC current used to run the mute
relay on the AF deck, and will carry about 40 milli-amps of (AC!) current
when the relay is energized.

These things will get clarified if you have and study the R-390A Y-2K Rev 3
manual.

I am not familiar with the T4XB, but if the mute or T/R connections are to a
"dry" relay or switch contact, that will operate the R-390A into mute mode
just fine.  *IF*, however it is a voltage that gets switched onto the
connections, with enough current to operate a small relay, then you must
provide that relay in order to not damage the circuits of the TX4B.  (A very
small relay would work well if this is the case.)

Sorry, I am
 not at all familiar with the Drake equipment.  I've heard good things about
them.  If someone sends me a T4XB or whatever, I'll gladly learn more! 
(HAH!)

Roy

Roy Morgan
k1lky at earthlink.net
K1LKY Since 1958 - Keep 'em Glowing!
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