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Re: [Yaesu] Problem in FT-101E -100v Circuit (Jerry Pittman)

To: Yaesu <yaesu@contesting.com>
Subject: Re: [Yaesu] Problem in FT-101E -100v Circuit (Jerry Pittman)
From: GGLL <nagato@arnet.com.ar>
Date: Sun, 15 Feb 2004 23:19:58 -0300
List-post: <mailto:yaesu@contesting.com>
I've forgotten to add, that you must realign the driver and final grid section for the upper bands (best if you perform a complete RF re-alignment as per manual), where you may note the worst tracking difference after C13 capacitor change.

Good luck
Guillermo - LU8EYW.

GGLL wrote:

Are your final tubes fine after C13 short?; that failure will turn very positive final tube's grid bias, which causes an indeed high plate current. Check them before you go to the shop. If I don't miss, C13 was a 100 pF rectangular old style mica cap. You could replace them with two 47 pF, 500V NP0 disc ceramics in parallel as I did in several 101's with good results.

Best regards
Guillermo - LU8EYW.

Jerry Pittman wrote:

Correction!!! Sorry Rick, I spoke to soon. I pulled the C13 cap from the
circuit and found that it had shorted. You were dead on for the diagnosis.
Now to go to the electronics shop tomorrow.


Thanks a Million!!
73 Jerry
WD4OIX

----- Original Message ----- From: "Jerry Pittman" <jerryp49@worldnet.att.net>
To: "R_Davis" <WD8JJA@arrl.net>; <yaesu@contesting.com>
Sent: Sunday, February 15, 2004 5:59 PM
Subject: Re: [Yaesu] Problem in FT-101E -100v Circuit (Jerry Pittman)





Thanks for the tip Rick. I checked that cap and it appears okay, so the
search goes on.
Jerry



----- Original Message ----- From: "R_Davis" <WD8JJA@arrl.net> To: <yaesu@contesting.com> Sent: Saturday, February 14, 2004 12:41 PM Subject: [Yaesu] Problem in FT-101E -100v Circuit (Jerry Pittman)




Check the coupling capacitor, C13, between the 12BY7A and the finals.
Rick, WD8JJA.

----- Original Message -----
From: <yaesu-request@contesting.com>
To: <yaesu@contesting.com>
Sent: Saturday, February 14, 2004 12:00 PM
Subject: Yaesu Digest, Vol 14, Issue 9




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Today's Topics:


1. Problem in FT-101E -100v Circuit (Jerry Pittman)


----------------------------------------------------------------------



Date: Fri, 13 Feb 2004 12:41:26 -0500 From: "Jerry Pittman" <jerryp49@worldnet.att.net> To: <yaesu@contesting.com> Subject: [Yaesu] Problem in FT-101E -100v Circuit Message-ID: <006e01c3f258$9b485ac0$6101a8c0@JerryPittman> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Reply-To: Jerry Pittman <jerryp49@worldnet.att.net> Message: 1

Hello to all,
HELP!  I wonder if anyone has run into this problem:

My 101E was just idling along while I was working on the computer the

=


other evening, when I started smelling something hot. I shot the rig

=


off immediately and found that the bias control (VR1) on the voltage =
control board (PB1547B) had over heated, as well as the (2) 10K =
resistors on either side of the control.


When I check the voltage at pin 5 of the 1547 board, I found that it

was


=


getting -160v instead of -100v. I went to the Rectifier board

(PB1076B)


=


and made tests there. When I disconnected the lead from the -100v =
terminal, the voltage shows -60v but with it is connected it shows =
-160v. With the lead disconnected I also tested it for AC voltage and

=


it shows 125vac as well as -60vdc.

I checked all the components on the 1076B board and found all okay,

but


=


just to be sure I hadn't missed something, I put in a used PB1076B

board


=


and found all of the same readings. I had already checked all of the

=


other voltages coming and going from the 1076B and all are correct =
except the -100v. The voltages from all of the transformer taps

appear


=


to be within range as well.

Does anyone have an Idea or run into this before?

Thanks in advance for any responses.
Jerry
WD4OIX
jerryp49@att.net------------------------------

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