[R-390] Re: R-390-A fix summary

[krk@ix.netcom.com]

Hi Jim,

  Thanks for your post on this topic. I'm curious about why you replaced the tube. Did 
you test the PTO tube and find it bad? Or does it test good but fail in the receiver (I 
hate those kinds of problems)? I ask because I have a URM25F signal generator that 
behaves similar to your 390.

Thanks,
Ken

> Recently, the bottom 350khz of ALL bands were found to be dead.  Tuning to a
> point below 350khz produced an abrupt loss of signal.  I confirmed that the
> symptoms were present above and below 8mhz, and within all the band groups
> defined from the coil and RF deck positions.  The likely suspect seemed to be
> the PTO, so I put the frequency counter on the output and confirmed that the
> frequency abruptly disappeated below about 350khz.
>
> I replaced the PTO tube, the symptoms disappeared, and the unit now works
> perfectly.  Of course I will recheck the alignment after the tube burns in
> for awhile.
>
> For the newbies on the list, I hope this might be helpful in the future.
>
> Jim