[Johnson] Viking II

[Ron Eveland W6QM]

Mike:

I recently purchased a Viking II-CD, with the AC cord cut off, in unknown
condition.  I opened it up, and it was unmolested, and everything
appeared to be original.  The first problem I found was that the LV choke
T1 was open, and it was not discolored or burned.  If you are reading 3K,
this is way too high, just do the math to determine your voltage drop at
350 VDC at 50 to 75 mils.  I replaced it with a used choke that was
identical in size that measured about 275 ohms, and it runs cool with a
voltage drop of about 25 volts across it.  I also mounted terminal strips
where the LV filter caps were, and put in new axial leaded caps, neither
the LV caps or the bias caps were any good, all were just dry, but not
shorted.  After replacing one of the 5R4 rectifiers this fixed the RF
section, and I was now able to get RF output, but no modulation.  I found
that most of the caps in the audio section were also bad, and many of the
resistors had gone way up in value.  I did change these out, but the big
problem was the modulation driver T3 had an open primary. I replaced it
with another transformer that was similar.  Finally everything worked OK,
and it sounded good on a monitor receiver with about 125 watts output.  I
also recently saw another Viking II for sale, and they indicated that T1
was also open, so the fiter choke may be a weak spot.
I have closed my unit up, but judging by the schematic you should expect
some resistance when measuring T3. You could disconnect the primary
winding from the circuit and recheck if you have any concerns.  Good luck
on your restoration. Ron, Cerritos, CA.

On Wed, 1 Dec 2004 11:54:04 -0500 <k4elv at bellsouth.net> writes:
> I am in the process of a complete restoration of this old baby.  The 
> only 
> problem I've run into are two tranformers and I'd appreciate any 
> comments.  L2, 
> the LV choke measured 2.5K on 2 VOMS and a VTM, rather than the 280 
> ohms the 
> manual describes.  I got another choke and it measured 3.2K.  Am I 
> dealing with 
> a mispreint in the manual or 2 fried units?  My second question has 
> to do with 
> the audio transformer T3.  I'm getting 4 - 5K between the primary 
> and 
> secondary.  Any thoughts.  73 Mike
> 
> 
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