[Henry] Henry Digest, Vol 34, Issue 1

[Dave Harmon]

Kevin.....
Thanks a lot....this is just the kind of stuff I was hoping to find out
about!
It hasn't been abused physically....just neglected....missing screws, some
dirt, a few marks here and there that look like they will come off with some
naptha.
I think I'll replace the AC power connectors....what seems to be the proper
connectors are available from Allied part # P-2406H-AB and S-2406H-CCT I
think I'll give it a quick operational test and make sure it works than
investigate what you mentioned and repair as needed.

If anyone else has any more info such as this I would be glad to hear it.

Thanks a lot.

Dave Harmon
K6XYZ[at]sbcglobal[dot]net
Sperry, Ok.


-----Original Message-----
From: henry-bounces at mailman.qth.net [mailto:henry-bounces at mailman.qth.net]
On Behalf Of Kevin LaHaie
Sent: Thursday, November 10, 2011 11:20 AM
To: henry at mailman.qth.net
Subject: Re: [Henry] Henry Digest, Vol 34, Issue 1

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)