[Johnson] another question

[Gary Schafer]

Could be a bad 6146 that runs away when it gets hot. Watch to see if the 
plate(s) get red when this happens. Also watch inside to see if the 
screen gets red.

Could be a capacitor in the plate circuit drifting.

If the clamp tube is operating properly you should be able to turn down 
the drive and or detune the drive and the 6146 plate current should drop 
down very low. If it does not then the problem may be that the drive 
level is drifting and the clamp is not working properly.

It is a good idea to put a second fuse in the low voltage power supply 
on the Viking II. If you get a short in the low voltage circuit it will 
cook the low voltage transformer before the main fuse will blow. It is 
too big to protect the low voltage supply.
I had it happen to mine. Lucky I was right there to see the smoke before 
it burned up.

73
Gary  K4FMX


KENNETH A CRIPS wrote:
> I have a minor and irritating problem with My Viking II.  It blows it's fuse 
> regularly
> Here is what it does.  when I am tuning it up going back and forth between 
> the controls
> bringing it into tune.  What happens is as I am watching the meter in the 
> plate position
> as I tweak and dip the plates the needle will slowly creep up and up, and if 
> I don't un key it will suddenly zoom up peg it's self and the fuse blows. I 
> have checked and tweaked, replaced, adjusted the voltage divider, idle 
> current, etc. this Viking II has the clamp tube and it is adjusted as it 
> should be. Does anyone have a tip as to what to look at. The radio sounds 
> great on the air, but it seems to be fragile, look at it to hard a it blows 
> the fuse.
> 
> 
> Speaking of fusing, the Viking II's fusing is awful, ditto for the Viking I. 
> It would be much better to have each of the power supplies fused on it's own 
> with the present 5 amp fuse used as a master fuse. Has anyone done this. 
> What I would like to know is what capacity fuses did you install for each of 
> the power supplies.
> 
>                                 Ken
> 
> 
> 
> 
> Kenneth A. Crips, Amateur Radio Station W7ITC, Cheyenne, Wyoming with The 
> Chew Crew II, Beezie, Chic' and Cowboy. Irish Terriers infamous for hogging 
> the bed. shredding the furniture, and spelunking garbage sacks. This trio 
> has the above human completely conned.
>  
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