[R-390] Carrier Level Meter Issues

Jim Whartenby old_radio at aol.com
Wed Mar 2 18:13:28 EST 2022


Checked the Y2K Manual, Rev 3, Chapter 7, and noted that there are no electrolytic capacitors listed for the RF Amplifier Sub Chassis.  Are you sure that the "little hidden jewel" is really an electrolytic or is there an error in the Y2KR3 manual?Jim

Logic: Method used to arrive at the wrong conclusion, with confidence.  Murphy

-----Original Message-----
From: hamfish at comcast.net
To: gary.biasini at shaw.ca; 'Jacques Fortin' <jacques.f at videotron.ca>; R-390 at mailman.qth.net
Sent: Wed, Mar 2, 2022 2:28 pm
Subject: Re: [R-390] Carrier Level Meter Issues

With a difference between the DB meter using AGC: Slow vs Medium, I would
first suspect C551. This is a 2mF 500VDC oil filled paper & foil cap. I’ve
never found a good one. Most are a dead short to ground. NTE makes a mylar
cap that works, 2mF @ 630VDC (from memory). 

 

That said, these receivers are old enough to collect social security. Not
knowing what previous owners have done to these receivers, first step if one
follows you home is to completely disassemble said receiver. All the BBOD’s
have to go. Orange Drops are a good replacement. Electrolytics have to be
replaced, don’t forget the bathtub cap on the rear panel (50mf @ 50V). Then
there is that little hidden jewel electrolytic in the RF deck, bet most
can’t even find it! 

 

While playing with the soldering iron check the resistors. Having reached
this point, mechanical alignment is next. Do not skip! Run through the
electronic alignment and find last bugs. The last bugs can drive a person
insane. Be persistent, most of the bugs can be fixed.

 

Craig,    

 

From: gary.biasini at shaw.ca <gary.biasini at shaw.ca> 
Sent: Wednesday, March 2, 2022 11:39 AM
To: Jacques Fortin <jacques.f at videotron.ca>; hamfish at comcast.net;
R-390 at mailman.qth.net
Subject: Re: [R-390] Carrier Level Meter Issues

 

Jacques, 

 

Thanks for weighing in. AGC voltage is -5VDC with Bandwidth 16kc, RF gain
fully clockwise, Limiter off.

 

DB meter starts at 45 in Slow AGC, pins the needle to the right for a second
or so in medium then settles on 58 and does not move in fast AGC. Going back
to medium, no change, back to slow pins the meter for a second and then it
settles at 45.

 

Regards,

 

 

Gary I. Biasini

  _____  

From: Jacques Fortin <jacques.f at videotron.ca <mailto:jacques.f at videotron.ca>
>
Sent: Wednesday, March 2, 2022 12:16:07 PM
To: gary.biasini at shaw.ca <mailto:gary.biasini at shaw.ca>
<gary.biasini at shaw.ca <mailto:gary.biasini at shaw.ca> >; hamfish at comcast.net
<mailto:hamfish at comcast.net>  <hamfish at comcast.net
<mailto:hamfish at comcast.net> >; R-390 at mailman.qth.net
<mailto:R-390 at mailman.qth.net>  <R-390 at mailman.qth.net
<mailto:R-390 at mailman.qth.net> >
Subject: RE: [R-390] Carrier Level Meter Issues 

 

Gary, does it make a difference when you try the AGC in Slow / Medium / Fast
??
When listening to a very strong local BCB station, what did you measure as
the AGC line voltage (TB102 3+4) ???

73, Jacques, VE2JFE in Montreal

-----Message d'origine-----
De : r-390-bounces at mailman.qth.net <mailto:r-390-bounces at mailman.qth.net>
<r-390-bounces at mailman.qth.net <mailto:r-390-bounces at mailman.qth.net> > De
la
part de gary.biasini at shaw.ca <mailto:gary.biasini at shaw.ca> 
Envoyé : 2 mars 2022 13:18
À : hamfish at comcast.net <mailto:hamfish at comcast.net> ; R-390 at mailman.qth.net
<mailto:R-390 at mailman.qth.net> 
Objet : Re: [R-390] Carrier Level Meter Issues

Craig,

I missed your message until just now.  It is in the AGC position.

Thanks for your message.

-----Original Message-----
From: hamfish at comcast.net <mailto:hamfish at comcast.net>  <hamfish at comcast.net
<mailto:hamfish at comcast.net> >
Sent: February 27, 2022 10:16 AM
To: gary.biasini at shaw.ca <mailto:gary.biasini at shaw.ca> ;
R-390 at mailman.qth.net <mailto:R-390 at mailman.qth.net> 
Subject: RE: [R-390] Carrier Level Meter Issues

Hello Gary,

Is the function switch in MGC or AGC??

Regards,
Craig

-----Original Message-----
From: r-390-bounces at mailman.qth.net <mailto:r-390-bounces at mailman.qth.net>
<r-390-bounces at mailman.qth.net <mailto:r-390-bounces at mailman.qth.net> > On
Behalf Of gary.biasini at shaw.ca <mailto:gary.biasini at shaw.ca> 
Sent: Sunday, February 27, 2022 9:00 AM
To: R-390 at mailman.qth.net <mailto:R-390 at mailman.qth.net> 
Subject: [R-390] Carrier Level Meter Issues

On my 1967 EAC S/N 4996, I have zeroed the meter as follows:

 

I tuned the radio to a dead space, unhooked the antenna and turned the RF
gain fully counter-clockwise.  I then adjusted R523 to zero the meter.

 

However, when I tune to 2 different local (strong) AM stations on the BCB,
even though I start to hear the audio when the RF gain is at 4.5 and it is
heard very loudly at 7, the carrier level meter only starts to register when
the RF gain is at 7.5 and at full clockwise, only registers 40 db.

 

I would like to troubleshoot this but don't know where to start.  If anyone
could guide me as to what to check, I would be most grateful.

 

Thank you. 

 

Gary

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