[ICOM] PRO III and shut down

[hamop]

Jim:
    I am using the self contained  PS 125 and 85 ICOM  with cables and  the 
Molex plugs on the ends. And the problem occurs with BOTH supplies, so would 
not think both would have corrosion and dropping voltages. And, the PS 85 I 
used  with another rig and it worked fine. I did unplug and replug both PS 
on the PRO III several times. The delay of a few seconds with 30 wpm CW 
keying is what gets me. Presently, I turned the PRO III on 3  minutes ago 
and a full 100 watt output. So instead of sending CW again for 15 seconds 
and having the power go down, I am letting it sit and every few minutes see 
if I can send 4-5 seconds. If it just sits there and suddenly stops 
transmitting in a few more minutes,  then I have a heating up driver or 
other componens of a final that are going out, more likely drivers since if 
one final goes the other should put out more than just 5 watts, even under 
unmatched final conditions.  Good thought though, and I did think of a 
faulty PS plug but not on two straight that have been working all OK til now 
. hi
73 Jim
San

-----Original Message----- 
From: Jim Hargrave
Sent: Monday, July 02, 2012 6:10 PM
To: ICOM Reflector
Subject: Re: [ICOM] PRO III and shut down

Sanford,

You could have a power cable problem.
I would suggest you place a voltmeter at the power connector on the rear of
the radio. Place it in transmit and see what happens when your RF power
drops. It should remain steady. If it drops significantly, check the voltage
at the power supply. don't depend on power supply meters for this check. Its
a common problem for in line fuses to become corroded and drop power when
under load. Even the spades can relax on the radio power connectors. If your
power cable has the in-line fuses, I would suggest replacing them and see if
that makes any difference. Sometimes they get cold solder connections within
the fuse it self.

    73s de Jim
       W5IFP



  >
  > On Mon, Jul 2, 2012 at 5:59 PM, hamop <k5yy at cox.net> wrote:
  >
  > >     Hello all ... need some assistance. Never had this
  > situation happen
  > > before. Today while operating on 20m CW I noted no output,
  > well maybe 5
  > > watts, and I thought maybe the PS125 had blown an internal
  > fuse for some
  > > reason. I was running about 50 watts to a Titan amplifier at
  > the time, my
  > > main setup for 3 years now. Well, rather than tear into the
  > PS125, I put a
  > > PS85 in line and again a full 100 watts immediately. So
  > thought the PS125
  > > had truly blown a fuse. Well, after another shutdown to about
  > 5 watts I
  > > thought the PS85 had also blown a fuse.
  > >    As one last effort, after about 5 minutes, I returned on
  > the PS125 and
  > > PRO III and a full 100 watts output again. I found out that
  > if I turned on
  > > the rig and did NOT hook the PTT line to the Titan, all
  > seemed to be OK
  > > with no "shut down".  But, even keying the amp with an EXTERNAL foot
  > > switch
  > > and trying to drive the amp, bang ... again just 5 watts out, but it
  > > returned to 100 watts after another 5-6 minutes.  Is the PRO
  > III or PS125
  > > and PS85 ( unusual for both to do it) heating up inside causing the
  > > shutdown by some quirk feedback from the Titan amp?  Seems
  > like if just
  > > barefoot straight to the antenna, I can transmit 100 watts as
  > normal with
  > > NO shutdown. Puzzling to me for sure. Appears since same
  > thing happened to
  > > the PS 125 and 85 that both should not have developed the
  > same 'shut down'
  > > issue. That leaves me wondering if my PRO III finals are
  > overheating some
  > > how?
  > >   Thanks for any suggestions.  Receive is fine the entire
  > time. If I shut
  > > down the PS and PRO III for just 3-4 minutes, the output may
  > drop quickly
  > > with about 20 seconds of CW and the longer units are off ,
  > the longer the
  > > power stays up.
  > > 73
  > > San K5YY


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