[Johnson] Valiant grid drive

John Lord [email protected]
Fri, 6 Sep 2002 12:59:12 -0500


I am hoping that someone in the group may have an idea to help me with a =
problem I can't seem to resolve.  I did a complete rebuild of a Valiant. =
 Setting the base line voltages according to the manual went smoothly.  =
When I tried to tune the rig up on any band above 40 I had very little =
grid drive (2 ma or less).  160 - 40 looked fine with upwards to 10 -12 =
ma.  Looking at V3 and V4 with a scope I get a normal looking sine wave =
on all bands except 10.  The 10 mtr wave shows a glitch of some =
sort.(see attached).  I've been told the ER had an article that spoke to =
this in the 122 VFO.  So here I am with a good looking waveform on all =
bands except 10 and the waveform level is the same on all bands except =
10 - down about 30%.  But when I try to tune up the grid drive just =
isn't there.  I replaced the drive pot with the solid state mod used in =
the ranger.  Swapped tubes, changed coupling and by-pass caps.  I =
reversed the leads on the top and bottom of L5.  Doing so, I am able to =
get drive on 10 and can peak the coil (b4 changing the leads I could not =
get a peak).  BUT the freq is no longer in the 7mc range but is now in =
the 4 mc range.  What in the world is going on?  Looking at L5 from the =
point closest to the chassis, does this connect to the switch or to pin =
6 of V3?  What about the band switch being miswired?  I've gone over the =
wiring but everything appears correct and the switch makes good contact =
at all points.  Thanks for the time.  73  Mike K4ELV


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