[Johnson] ranger fuse

[Jerry Kessler]

Dave,

For safety's sake as well as complying with the current NEC, it's a 
good move to get the neutral off the chassis for those 115 VAC 
applications within 230 volt systems.  I've done this with the 
Collins 30S-1 and National NCL-2000, using 4-wire cords and plugs - a 
much better arrangement.  The Johnson Thunderbolt can benefit too and 
I believe the Invader 2000 power supply takes its lineage from the 
Thunderbolt so it makes sense there, too, as you have noted.

Jerry Kessler
N4JL

At 04:13 PM 2/16/2006, David C. Hallam wrote:
>I think that Johnson relied on the assumption that good hams always securely
>grounded their equipment.  The manual states that the equipment should be
>grounded with a wire that is not a multiple of a 1/4 wave length on any
>frequency of operation.  "GOOD LUCK"  I have just acquired a Viking Invader
>2000.  The chassis of the HV power supply is the neutral side of the 115V
>supply for things like fans, LV transformers, etc.  As long as you operate
>from 240V with a neutral that is grounded, I suppose this is safe.    The
>exciter portion of the Invader is not wired that way.  But if you do operate
>from 115V, you had better be sure the outlet is wired properly.  I am
>considering rewiring the HV PS and run 115V neutral wires isolated from the
>chassis.
>
>David
>KC2JD
>
>-----Original Message-----
>From: johnson-bounces at mailman.qth.net
>[mailto:johnson-bounces at mailman.qth.net]On Behalf Of K6JEK
>Sent: Thursday, February 16, 2006 3:48 PM
>To: johnson at mailman.qth.net
>Subject: Re: [Johnson] ranger fuse
>
>
>
>I've been taught to never put a fuse in the neutral line.  If there is
>a fault that puts the AC hot line somewhere that it shouldn't be and
>the neutral fuse blows, the danger still exists possibly right at your
>fingertips.   There have been many discussions of this topic on this
>forum including a nice post in defense of the Johnson design which
>maybe made sense at the time given the common wiring of the time.   But
>it doesn't make sense now especially for a 50 year old  radio in which
>failing components are likely.
>
>On the AC bypass cap issue --  replacing them is a great idea.  We need
>to make sure they are capacitors designed for the purpose not the
>ordinary vanilla disc ceramics we have in our junk boxes.  For across
>the linethey should be a type Y capacitor.  These are readily available
>from Mouser, Newark, Digikey.   Here's a link the Vishay/Sprague
>website that describes theirs:
>http://www.vishay.com/docs/23092/aclinecp.pdf
>
>They seem to have changed part numbers since I bought my supply of
>X1/Y2's which in addition to being the safe part for the job have the
>bonus of being a beautiful electric blue.   What could be more
>appropriate?
>
>Jon, K6JEK
>
>On Feb 16, 2006, at 11:04 AM, SBJohnston at aol.com wrote:
>
> >
> >> it's worth noting that the plug fuse values are asymetrical
> >> eg... they are NOT the same value..and arent supposed to be. see
> >> manual
> >
> > That's why I used two when I modded my Ranger...
> >
> > Steve  WD8DAS
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> >
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