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

[GGLL]

    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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>>>>   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"
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>>>>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------------------------------
>>>>
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>>>>
>>>>End of Yaesu Digest, Vol 14, Issue 9
>>>>************************************
>>>>
>>>>        
>>>>
>
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