[ICOM] IC-756PRO - Thumping, flickering screen, reset

[Frank A. Ellis]

I had exactly the same problem with my PROII one time,
and as it turned out, I had accidentally bumped the
current limiter adjustment on the Astron power supply,
causing it to limit to about 10 amperes. 

I felt really humble when I discovered the real
problem, after some serious troubleshooting.

Don't know if your friend has the adjustable version
or not, but even if not, he may want to check the
current output.

73 Frank W3UHF



--- "David J. Ring, Jr." <n1ea at arrl.net> wrote:

> A friend has a problem with a ICOM IC-756PRO:  It
> starts to thump when on 
> QSK in CW mode, the screen has been seen to go
> temporarily blank for a 
> quarter second or so and then return, but sometimes
> reseting the 
> microprocessor and rebooting the radio.
> 
> The problem appears to be dependant on either r.f.
> power, or power supply 
> loading as when the r.f. power output control is
> backed off to about 40 
> watts the thumping cuts down.
> 
> The radio just started doing this yesterday - his
> antennas are snow 
> covered - but SWR appears normal, switching bands
> and antennas does not 
> change the problem.
> 
> Has anyone seen a similar problem before?  He has a
> 35 ampere Astron power 
> supply that's 10 years old.
> 
> The '756 is about two years old.
> 
> What's your guess?  Is this a known problem, or is
> it likely the power 
> supply has problems with regulation?
> 
> The problem with measuring AC ripple on the power
> supply with an 
> oscilliscope is that it is difficult to filter out
> the r.f. from the running 
> transmitter.
> 
> 73
> 
> David Ring N1EA 
> 
> ----
> Your Moderator: Dick Flanagan K7VC,
> icom-owner at mailman.qth.net
> Win a new Icom IC-756 PRO III and help QSL/QTH.net
> Details at: http://mailman.qth.net/
> 



		
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