[Boatanchors] Boatanchors Digest,HRO-500

[radioman390 at cs.com]

 Hi...I've had several HRO500s over the years and even TWO HRO-600s which I loved. The 600 was probably the best VLF receiver I've ever had or tried.

Both my 500s had an intermittency problem, which I localized to a subchassis on the radio. If you are facing the front, and put your left hand about 3/4 of the way back along the chassis, there's a subchassis which has the old style mica trimmer capacitor. I suspect that as it ages, it changes value. I recall that adjusting it would "unlock" the radio, but as time went on the screw adjustment would have to come out further and further. until the screw dropped out. It's been at least 20 25 years since I had one so the details may not be exact. Also, if memory serves correctly, the bushings that allowed two 1/4" shats to connect would work loose. Check to see if the set screws are tight.

That's all I can offer.

Matt



[Boatanchors] National HRO-500 Intermittant



 


 


 

-----Original Message-----
From: boatanchors-request at mailman.qth.net
To: boatanchors at mailman.qth.net
Sent: Mon, Jun 15, 2009 10:50 am
Subject: Boatanchors Digest, Vol 65, Issue 19










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Today's Topics:

   1. OT:  QST and CQ Magazines Giveaway (Cal Cotner)
   2. Re: HAMCOM 2009 (Carl)
   3. National HRO-500 Intermittant (Jim Wright)
   4. Re: National HRO-500 Intermittant (Jim Wiley)
   5. Prewar Creativity (Michael Tauson)
   6. Re: National HRO-500 Intermittant (Carl)
   7. Re: Prewar Creativity (Carl)
   8. HT-40 Question (Lee Buller)
   9. Re: HT-40 Question (VE7SL at shaw.ca)
  10. Re: HT-40 Question (Rodger)


----------------------------------------------------------------------

M

Message: 3
Date: Sun, 14 Jun 2009 19:07:27 -0700 (PDT)
From: Jim Wright <hatisland8 at yahoo.com>
Subject: [Boatanchors] National HRO-500 Intermittant
To: boatanchors at mailman.qth.net
Message-ID: <126714.47812.qm at web44712.mail.sp1.yahoo.com>
Content-Type: text/plain; charset=us-ascii

I've got a HRO-500 with a strange problem and hoping someone out there has seen 
something like this before.

If used every day it works fine.  But if it sits for a few days, then when it's 
turned on it operates for only about 30 seconds.  For that 30 seconds or so the 
SSB or AM stations come in normally, and then the signal strength (and the S 
Meter) start to slowly decay until there is no signal received and the S Meter 
gradually goes to 0.  During the final few seconds the audio distorts - sort of 
like AM splatter  sounds like.  Problem occurs on all bands and filter 
positions, and both SSB and AM. The radio PLL remains "synchronized" (no red 
light from synchonizer) and the 12, 11, 10 volt power measures okay.  After the 
signal goes away there is some audio hiss but that's all.    

Turning the set off and on again a single time repeats the same thing.  However, 
after turning the power off and on four or five times the radio resumes normal 
operation and runs without problem.   

At first, I thought it must be a bad cap but it seems like if that was the case 
it wouldn't ever operate normally after the series of turning it off and on.  I 
wiggled transisters in their sockets without any changes but haven't replaced 
any.  It acts like the problem is somewhere in the RF path up to the audio amp.  


Anyone experienced like this with a HRO-500?

Thanks.


      

*********



 

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