[AMRadio] SB-10 Modification (was DX-100B on Phone - bad audio distortion / oscillation)

[wb3fau at att.net]

very  interesting Rick.  Not  enuf  drive.  Clamper not  working  right.
 Are there  any  waxy coupling/ bypass capacitors  anywhere in these  circuits?  Grid  drive is a very common problem in these rigs.  Do  you have any spare  12BY7s  or 5763 tubes?  [hope I  got the  numbers  right]
for the buffer and  driver  tubes.  Less   grid drive  on 10m  is common.
But  you should get plenty on 40m.  8ma. or  more.  If not,  start  checking parts in this  area-  everything-  tubes, caps and resistor  values.  73 Russ.

--- On Fri, 12/9/11, Rick Poole <wa1rkt at arrl.net> wrote:

> From: Rick Poole <wa1rkt at arrl.net>
> Subject: Re: [AMRadio] SB-10 Modification (was DX-100B on Phone - bad audio distortion / oscillation)
> To: amradio at mailman.qth.net
> Date: Friday, December 9, 2011, 6:50 PM
> At 06:11 PM 12/9/2011, wb3fau at att.net
> wrote:
> 
>  >>>>>
> >Rick, the DX-100 vfo  is not  very
> stable.  it  is OK  for 
> >AM.  using it on SSB would be a  real 
> challenge.  I   agree  with 
> >others,  use  something newer  on SSB.
> <<<<<
> 
> Yeah, I'm backing out the SB-10 mod now.  Removed the
> (very FAT) coax 
> that goes from the driver output to the farthest corner of
> the 
> chassis to the coax connector that is supposed to go to the
> SB-10 
> (but up to now, just goes to a jumper to another coax
> connector that 
> goes to the finals grids), and replaced it with a 1" length
> of bare 
> wire to the grids of the finals.  Now, from just that
> change, I get 
> plenty of grid current whereas before I could only get
> about half of 
> what I should get.  Still can't get it to give me the
> right 
> indications for adjusting the clamping pot, though. 
> But, making progress.  :-)
> 
> Rick WA1RKT
> 
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