[Henry] Henry Digest, Vol 34, Issue 1

[Kevin LaHaie]

Hi Dave

Congrats on getting the 3K Classic X MkII.  I have one of these amps and 
had a very tough to diagnose problem with it, and ended up having the 
SAME problem on my 2K Classic X.

In both cases, the copper strap that goes from the load capacitor to a 
feedthru which goes to the 'L' coil under the chassis, must get hot 
enough to crystallize
the nuts and washers that connect that strap.  It ends up on power 
peaks, after a few minutes of operating, shunts the RF to ground, giving 
a 'clipping' of the output when it finally fails, the output signal 
clips but you can't see any indication on the meters.  One had actually 
broken the insulator, the other just developed a very high resistance - 
the nuts and bolts were all 'blued' and making poor contact.  A good 
sanding of the copper, and replacement of the nuts and washers solved 
the problem.  Same problem on 2 different amps usually means it's a weak 
spot, and should at least be looked at.  You will need to remove the 
nuts to ensure it hasn't started on yours.

The only other problem has been on the fixed capacitor 'rail', with the 
forward most pair of doorknob capacitors.  These 2 capacitors are 
strapped together, and each has a little 'L' bracket to hold it onto the 
insulating 'rail'.  The bracket for the capacitor closest to the front, 
is pretty close to some of the hardware on the front of the RF deck.  
There really doesn't have to be the 2nd bracket for the capacitor, so I 
took it off, and relied on the copper strap that binds the capacitors 
together, removing that 'close to ground' metal.  another friend with a 
5K suggested that fix, and sure enough when I got there to perform the 
mod, there was evidence of an arc there.

Other than that, the tube is a brute, these amps tunes very easily, no 
worries about warming up - a great amp!

The only thing some people do is increase the number of air holes 
drilled around the tube - some earlier amps only had 1 ring of holes 
around it, and doing the math, it's a restriction of air.  Look at Radio 
Dan's pictures of his 3KX MKII and you'll see he has more than doubled 
the amount of holes that pass air from under the chassis to the tube.  I 
have an earlier amp, and want to make that change - I also think it 
contributes a bit to the fan noise level, which of course Henry is 
famous for!

Most important, is to Enjoy!

73 Kevin K7ZS (with a pair of 2K Classic X's - 1 Grey, 1 in the factory 
Black paint scheme, and a 3K Classic X MkII)


On 11/10/2011 10:01, henry-request at mailman.qth.net wrote:

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>     1. Henry Classic X MKll (Dave Harmon)
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> Message: 1
> Date: Wed, 9 Nov 2011 21:19:12 -0600
> From: "Dave Harmon"<k6xyz at sbcglobal.net>
> Subject: [Henry] Henry Classic X MKll
> To:<henry at mailman.qth.net>
> Message-ID:<003501cc9f57$868b0290$93a107b0$@net>
> Content-Type: text/plain;	charset="us-ascii"
>
> I just bought a Classic X MKll with a 3CX1200A7.
>
> Are there any 'do's and don'ts' with this amp?
>
> I also have had a 3K-A I bought new so I am not completely unfamiliar with
> the Henry units.
>
> Any comments from anyone would be appreciated.
>
> Thanks.
>
> Dave Harmon
> K6XYZ[at]sbcglobal[dot]net
> Sperry, Ok.
>
>
>
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> End of Henry Digest, Vol 34, Issue 1
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