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

Jerry Pittman jerryp49 at worldnet.att.net
Tue Feb 17 12:31:18 EST 2004 

Hello again Guillermo,
I was able to find a package of Hi-Q 82PF 10% 1k volt S3N Ceramic Caps to
use as replacements in my 101E.  I also checked the same 80pf cap at the
transmit relay and it is showing signs of resistance break-down as well, so
I am going to replace both of the original moulded mica caps with the new
ones while I'm in there.

Thanks again for all of the tips to all,
73 Jerry
WD4OIX


----- Original Message ----- 
From: "GGLL" <nagato at arnet.com.ar>
To: "Yaesu" <yaesu at contesting.com>
Sent: Monday, February 16, 2004 5:40 PM
Subject: Re: [Yaesu] Problem in FT-101E -100v Circuit (Jerry Pittman)


>     Hello Jerry, I suggest not to replace that cap. with a similar one
> because sooner or later you'll have the same problem. They're prone to
> have losses (= lower Resistance) with time. You can try a pair of disk
> ceramic capacitors (NP0) or a silver mica one, of not less than 500 V
> working voltage (nearly 350V on standby at 12BY7 plate plus some
> -60..-80V on final grids, that makes a total V of 430V across this
> capacitor).
>
> Glad to help you
> Best regards
> Guillermo - LU8EYW.
>
> Jerry Pittman wrote:
>
> >Hello Guillermo,
> >Yes, you are right about the finals.  I had discovered that one of the
> >6js6c's had gone shorted on several pins after testing them on my Sencore
> >tube tester.  The driver also showed greatly reduced life test, so I have
a
> >complete set of valves on the way.  I'm thankful I got the tip on the C13
> >cap before the new tubes arrived.  I was starting to think their failure
> >cause the voltage problem and not the other way around.
> >
> >That cap is an 80pf 1KWV so if they don't have it, I'll try matching up a
> >couple of 40pf 500v like you suggested.  Thanks for the suggestion, since
> >they probably won't have the original mica cap available.
> >
> >73 Jerry
> >
> >
> >----- Original Message ----- 
> >From: "GGLL" <nagato at arnet.com.ar>
> >To: "Yaesu" <yaesu at contesting.com>
> >Sent: Sunday, February 15, 2004 9:20 PM
> >Subject: Re: [Yaesu] Problem in FT-101E -100v Circuit (Jerry Pittman)
> >
> >
> >
> >
> >>    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 at worldnet.att.net>
> >>>>To: "R_Davis" <WD8JJA at arrl.net>; <yaesu at 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 at arrl.net>
> >>>>>To: <yaesu at 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 at contesting.com>
> >>>>>>To: <yaesu at 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 at worldnet.att.net>
> >>>>>>>To: <yaesu at contesting.com>
> >>>>>>>Subject: [Yaesu] Problem in FT-101E -100v Circuit
> >>>>>>>Message-ID: <006e01c3f258$9b485ac0$6101a8c0 at 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 at 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 at att.net------------------------------
> >>>>>>>
> >>>>>>>_______________________________________________
> >>>>>>>Yaesu mailing list
> >>>>>>>Yaesu at contesting.com
> >>>>>>>http://lists.contesting.com/mailman/listinfo/yaesu
> >>>>>>>
> >>>>>>>
> >>>>>>>End of Yaesu Digest, Vol 14, Issue 9
> >>>>>>>************************************
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>_______________________________________________
> >>>>Yaesu mailing list
> >>>>Yaesu at contesting.com
> >>>>http://lists.contesting.com/mailman/listinfo/yaesu
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>_______________________________________________
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> >>>
> >>>
> >>>
> >>>
> >
> >
> >
> >
> >
>

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