[Yaesu] Re: Yaesu Digest, Vol 16, Issue 3

[marv]

I had same problem with FT-101 would tune up to 100 watts out, and almost
immediately
the output would drop 25 watts. Turned out to be 12by7 driver tube.
Marv 
 
-------Original Message-------
 
From: yaesu at contesting.com
Date: Friday, April 09, 2004 11:03:07 AM
To: yaesu at contesting.com
Subject: Yaesu Digest, Vol 16, Issue 3
 
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Today's Topics:
 
    1. Low output on FT902 (Jon Klinkhamer)
 
 
----------------------------------------------------------------------
 
Date: Fri, 9 Apr 2004 10:57:37 -0400 (GMT-04:00)
From: Jon Klinkhamer <jonklinkhamer at earthlink.net>
To: yaesu at contesting.com
Subject: [Yaesu] Low output on FT902
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Reply-To: Jon Klinkhamer <jonklinkhamer at earthlink.net>
Message: 1
 
 
 
I=E2=80=99m replacing all my tubes (6146B=E2=80=99s and 12by7) with new one=
s. Using 6146W=E2=80=99s for the finals. The reason is I=E2=80=99m seeing =
low output. The output is maybe 80 Watts at the low bands to just barely hi=
tting 100Watts at the high bands. I neutralized the finals as best I can an=
d aligned the Tx drivers without any noticeable changes. But the thing I al=
so noticed was that during my 10 second tune up, my wattmeter would show th=
at my power was drifting downward by about 10 watts or so. My thinking is t=
hat maybe one of those big old caps is not holding the charge. I suppose th=
e electrolytic dries up after 20 or so years. Does anyone have any comment=
s on this before I start to replace components? One thing I=E2=80=99m going=
  to do is check the bias voltages on the tube sockets and make sure they
ar=
e within the noted voltages in the service manual.=20
 
=20
 
Thanks for reading,
 
Jon
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End of Yaesu Digest, Vol 16, Issue 3
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