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

[Joe - WDØM]

That same problem happened to me - and the same cause - I bumped the 
adjustable amperage and voltage settings on the Astron VS-35M.  Reset those 
and the problem went away.  Thank goodness!

73,
Joe
WDØM

At 09:56 AM 1/29/2005, Frank A. Ellis wrote:

>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


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