FWD: RE: [Collins] Need KWM2 help

[John Page]

     THANK YOU Dr Jerry.I replaced C106 with a NOS but still had the 
problem. I then paralled C106a with a new fresh axial 20mfd 450v 
electrolitic and the problem is GONE. This is the cap that goes from the 
plate of V15 ,the prod det, to ground. That and all the new orange drops I 
just put in the avc amp, prod det, and audio stages and the receiver now 
sounds better than ever.
     I want to thank everybody that responded and especially Jerry, K0CQ. As 
uasual he was right on the money. Thanks again everyone, John



John Page K4KWM
Hollow State since 1953
(ex W8PKU,N8BLB,NA8O)





>From: "Gerald Johnson" <geraldj@mail.isunet.net>
>Reply-To: <geraldj@mail.isunet.net>
>To: <collins@mailman.qth.net>
>Subject: FWD: RE: [Collins] Need KWM2 help
>Date: Wed, 26 Nov 2003 08:51:49 -0600
>
>---------- Original Message ----------------------------------
>From: "Gerald Johnson" <geraldj@mail.isunet.net>
>Reply-To: <geraldj@mail.isunet.net>
>Date:  Wed, 26 Nov 2003 08:49:29 -0600
>
>Open electrolytic you didn't test. That would be my first test. The one 
>bypassing the receiver low voltage. When its open or has a high series 
>resistance it lets feed back go through the whole radio, and electrolytics 
>tend to fail with old age that way.
>
>73, Jerry, K0CQ, Technical Advisor to the CRA
>
>---------- Original Message ----------------------------------
>From: "John Page" <k4kwm@hotmail.com>
>Date:  Wed, 26 Nov 2003 04:15:27 +0000
>
> >I have aKWM2 that is giving me fits. It hasnt beat me yet but its winning 
>so
> >far. So read the following and if anyone can suggest anything, I sure 
>would
> >appreciate it.
> >
> >Turned it on the other day and everything seemed normal. Transmit and
> >receive worked fine. Then I turned up the gain and "wow" feedback like 
>mad.
> >Loud squeal. Starts at about 1/3 gain. Here is what I have done so far.
> >
> >* Swapped out V15 and V16 with known good tubes. no help
> >* Opened the audio line at the gain control. problem gone
> >* So I fed an audio signal in at the gain control and audio section 
>worked
> >normal.
> >* Reconnect gain and problem back.
> >* Opened line from T5 to V15 (avc rec). Problem still there.
> >* So I now think the problem is in the avc rect and prod det circuit.
> >* Remove the coupling cap from V15A to V15B and problem still there.
> >* Ok so maybe its in the prod det.
> >* All voltages and res. measurements ok.
> >* Replaced all caps in the prod det circuit and checked all res. problem
> >still there
> >
> >So if anyone can shed some light maybe I can still whip this guy. Thanks 
>in
> >advance. John
> >
> >
> >
> >John Page K4KWM
> >Hollow State since 1953
> >(ex W8PKU,N8BLB,NA8O)
> >
> >_________________________________________________________________
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> >
> >
>

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