[Milsurplus] Harris RF-590A & R-2368/URR Problems

[Todd, KA1KAQ]

It's been a few years (1990s) but I'm going to hazard a guess that it's
pesky tantalum caps that have expired or are on the way out. Seems there
were a number of them in there that caused issues. I recall the unit I used
back then with a pair of 590s in one rack next to the matching KW
transmitter seemed to always have one receiver missing, pulled out for
servicing. It was always powered up but idle 95% of the time.

~ Todd, KA1KAQ/4

On Fri, Mar 17, 2017 at 5:27 PM, john <jii at centurytel.net> wrote:

> Just wondering; if there are any Owner's/Users, of these Radios, who might
> have some 'Trouble Shooting Ideas' for me.
>
> Please allow me to describe the Issue(s); and see what you think or might
> recommend as a 'starting Point'?
>
> The Issue(s); are Low, Low,  Sensitivity in both Radios...........both
> Used to work very well and had a very high degree of Sensitivity.  Both
> Radios Pass the 'Bite' Self Testing on Power Up and there are no 'error
> Codes'. Prior Functioning of Radios had Signals,  World Wide,  from a 8'
> Antenna Wire stuck in a Antenna Input Jack.
>
> I have never had these Radios connected to any type of outdoor Antenna.
> Only a short piece of wire inserted into the Antenna Input.  Radios have
> not been operated in any High RF Field; since I have owned them.  They
> have; however; been continually plugged into AC Line Power when 'Off'.
>
> Very few B.C. Stations are now heard; and those I can pull; quite weak.
> Can't pull WWV @ 5mc.; 10mc  WWV very weak.  Not much on 20 meters, 40
> meters, or 75 meters.
>
> I was going to try and by pass the built in pre-selector.  Thought I had a
> 'Jumper' for that.  Turned out; I did not; at least not the Right Size.
> (does anybody know what size and Type the Internal Coax runs are, in the
> Radio; between sub Chassis?  (what connectors)?? In any event; I replaced
> one pre-selector with a Brand new one out of the Package.  No improvement;
> as far as Sensitivity is concerned.
>
> So; the Question is:  what could possibly be affecting TWO Radios, (that
> used to work just fine);........Sensitivity wise;  when the only thing they
> have been doing is plugged into AC Power and mostly turned off?
>
> Batteries on the Control Board do not seem to be leaking.
>
> I do not have ready access to Test Equipment; at my present location.  I
> can say; that I have tried to use a Millen Grid Dip meter as a Signal
> source; and it is hard to get a Signal into the Radio using the G.D. Meter
> as an Oscillator; from 5 ft. away.  So; these Radios; you might say; are
> basically 'Dead'....................
>
> Does anyone have any Ideas or experience similar to Mine; with these
> Radios?
>
> I am beginning to wonder if they might have swallowed some sort of Voltage
> Spike off of the AC Line; that went into the Radios; even though AC Power
> switch was 'Off'?
>
> I see where there is some sort  'Relay' in the Front  End Input Filter on
> these Sets; but I only figured that is for Antenna Input Over Load?
> Besides; I think this Relay is suppose to 'Self Check' at every power up;
> and as I related;  Both Radios pass all 'Bite' Testing.
>
> Any Help or Suggestions much Appreciated.
>
> Thank you.
>
> John
>
> ARS K9JII
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