[Milsurplus] "Sick" R390/URR

[Greg Mijal]

John:

I havn't worked on the non A but have fixed a few 390A's.
A good place to start is to make sure all the power supplies are within
spec's.  Even the filament supply.
Another problem area can be the IF assembly.  They can create an over all
low reception problem from the bottom to the top of band coverage.  If you
have spare tubes for the IF then this would be a good time to try them out.
That's all I can think of for now.
Good luck, I'm sure you will love the little monster when you get it squared
away.
73's
Greg
WA7LYO
Kinston NC
----- Original Message -----
From: "John King" <k5pgw at yahoo.com>
To: <milsurplus at mailman.qth.net>
Sent: Sunday, March 23, 2008 7:56 PM
Subject: [Milsurplus] "Sick" R390/URR


> Hello Folks!! I have been tinkering with a Collins
> made R390/URR for several days now and am not making
> much progress. I have had it on the shelf for about 20
> years.
>
> I have removed all connectors and applied De Oxit . I
> have removed all tubes and treated the tube sockets
> with De Oxit. I have done some tube swapping with
> little result. I have not chanced the 6AJ5 because I
> don't have one. I feel like the receiver is deaf
> compared to other receivers I have such as KWM 2 and
> several Drakes.
>
> It receives after a fashion but has low sensitivity
> and amplification within the receiver. It works on the
> AM broadcast band with "not very loud" audio. I am
> using a 70volt line transformer to 4 ohm Hammarlund
> speaker. I copy a few CW signals on 160 meters and CW,
> AM, and SSB signals on 80 meters. The shortwave bands
> in the 6 mhz and 9 mhz are received fair. I get weak
> WWV signals on 5, 10, 15 mhz. I hear nothing above the
> 12 mhz shortwave bands that I consider receiving a
> useful signal.
>
> I don't know the heterodyne scheme so I don't know if
> various bands just aren't there because of hetrodyne
> problems.
>
> My "gut" feeling is that the RF stage isn't working
> correctly as well as "some bands just aren't there"
> for some reason or other.
>
> If you have experience with the R390/URR and have
> encountered these symptoms, I would greatly appreciate
> your suggestions and guidance. Thanks for reading. 73,
> John, K5PGW
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