[Johnson] Viking Invader need some ideas

[Mark Foltarz]

Joe,

  Wow, there seems to be a whole gaggle of Invader 200 / 2000 coming 
 back  on the air. 

  If you are noticing the shielding starting to degrade that means the set has
probably been stored in a relatively high  environent. The shielded audio wire
may easily be replace with any flexible coax with a good braid. The
characteristic impedance of the coax is completely irrelavant in this
application. But of course you could always see how it works before replacing
it - the situation may not be as bad as perceived.

  The tune up procedure in the manual is somewhat lame. However, follow it the
best you can and if power out is way low and everything seems OK, go back an
peak up T2.  
  
  Before attempting an alignment, make sure all the tube shields are back in
place.
 
  I noticed that on my Invader 2000 the trimmer variable capcitors (near the
slug variable inductors) developed corrosion on the lock nut. This corrosion
dratically effected the connection to the circuit. You will notice unstable
results while trying to adjust the affected caps. 

 Check the electrolytics and bypass caps. I was surprised that the filters in
the high voltage section reformed completely, however, the bias supply caps
were shorted.

 Of course check the bias per the manual or you will be replacing the 6146's.

 By the way, if you want to make antother dial for your Invader, the artwork 
is available on BAMA.

73
de KA4JVY
Mark

  
--- Joe Y <bbc39668@yahoo.com> wrote:
> Hello all,
> Am finally getting around to my Invader 200 and
> preparing to go through it and hopefully get it
> airworthy once again but I have a question and request
> for some info.
> Upon inspection of the rig I am noticing that Johnson
> used a shielded type cable in what at quick glance
> appears to be the speech amp section as I can see it
> is wired to the Audio Pot. This shielded cable seems
> to have broken down and has become "crispy" and falls
> apart easily and I am quite concerned about it giving
> me problems.
> Can anyone out there familiar with this rig or that
> shielded cable offer any advice on where to obtain
> this type of wire or if unshielded wire can be
> substituted?
> Also are there any other quirks with this rig I should
> beware of as I start going through it?
> Thanks for any help,
> joe
> 
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