In the interim, you might try pulling one or both of the 5814 tubes from the
calibrator circuit and swap them into your AF deck to see if that corrects
the problem or not...
73...Jordan VE6ZT
----- Original Message -----
From: "Tom M. via R-390" <[email protected]>
To: <[email protected]>; "Jacques Fortin" <[email protected]>
Sent: Wednesday, April 10, 2024 4:56 AM
Subject: Re: [R-390] R-390A blown fuse, now distorted line and local audio
Very good advice. Thanks for your prompt response. I did not have any new
5814 on hand so I ordered one and will pop that in and give it a try.If
that's all it is, that would be great.
ThanksTom
On Tuesday, April 9, 2024 at 07:46:15 PM CDT, Jacques Fortin
<[email protected]> wrote:
Hi Tom,
My guess is that V601B filament gave up.
So you have the 1st audio stage working, most probably, but the cathode
follower stage that follows is inactive.
Quick fix: change V601 and check if the audio returns to normal.
If not, more investigation in the AF chassis is due.
That could be also the V602 that developed a gas leak....
Let us know what you found, anyways.
73, Jacques, VE2JFE in Montreal
-----Message d'origine-----
De : [email protected] <[email protected]> De la
part de Tom M. via R-390
Envoyé : 9 avril 2024 19:38
À : [email protected]
Objet : [R-390] R-390A blown fuse, now distorted line and local audio
Hello all,
looking for advice to help fix this problem.
I was operating my radio today when it exhibited some funny business,
flickering dial lamps and then sudden OFF.Found 3A fuse was blown (but B+
fuse OK).
Not knowing what else to do I replaced the fuse and supervised the power
on. It powered on normally with no other fuse blowing or flickering, but I
have low and somewhat distorted audio on both the LINE and LOCAL audio
circuits.
Initially thought the AGC was out so I switched IF decks; same issue.
I checked the audio at the DIODE LOAD through an amp and it is
lovely/normal.
So Q: where should I start looking to repair this audio problem?I don't
know if the blown fuse was a red herring or not but it sure seemed real
like bad stuff was happening right before.
Twenty five years ago I changed C603A/B (30uF caps on 1st AF AMP) and the
PS electrolytics, so even though the originals are gone the "new" ones are
25 years old. BTW the PS has the orig rectifier tubes in it; no solid
state.
So to sum up, DIODE LOAD sounds fine, LOCAL and LINE audio are low and
distorted after blowing the fuse.
Advice?
Thanks in advance.Tom
______________________________________________________________
R-390 mailing list
Home: http://mailman.qth.net/mailman/listinfo/r-390
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
______________________________________________________________
R-390 mailing list
Home: http://mailman.qth.net/mailman/listinfo/r-390
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
______________________________________________________________
R-390 mailing list
Home: http://mailman.qth.net/mailman/listinfo/r-390
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
