[Premium-Rx] Help! - WJ HF-1000A turns on and off by itself

[Dr. Walter Salmaniw]

At 05:19 PM 23/10/04, Odd-Jorgen Sagdahl wrote:
>Hi all,
>
>I am on a listening expedition (KONG11, see www.kongsfjord.no for details)
>and we have made some excellent catches. Just now, my WJ HF-1000A started to
>turn itself on and off by itself. That is - it restarts. The S-meter light
>is still on, but the rest of the radio is dark, and then it reboots like
>when you turn it on. This happens with 10-15 seconds intervals.
>
>I have had the radio in use for more than 24 hours, but this has never
>occurred before. However, after turning it off for a while it seems to work
>normally - at least for a now ...
>
>Anyone have any experience with similar behavior? Any input would be greatly
>appreciated. I have other receivers as well, but none that beat this one
>(when it works).

OJ, I've experienced similar problems with several mil-spec 
receivers.  From my non-technical background, and recalling what the 
"experts" on our list have said (thanks fellas!), there's usually a heat 
sensitive component problem.  When the unit warms up sufficiently, the 
component goes US and the receiver fails.  It's a very tough thing to 
diagnose and locate, but one of the best pieces of advice was to use a 
cooling spray and spray various components for a few seconds to see if it 
brings the receiver back to life.  If it does, that's the component to 
replace.  Of course it has to be non-functioning before it happens.  I've 
learned to keep my hot running gear cool, with the use of fans, etc!  Good 
luck, and let us know if you could locate the source of the problem.  It 
happened to me one year during a DXpedition to Grayland, WA.  Luckily, I 
had a back up receiver to use until I repaired the offending 
unit............Walt Salmaniw, MD   Victoria, Canada.