[Heathkit] Troubleshooting my HW-101

[Kenneth G. Gordon]

On 21 Apr 2007 at 14:19, Ted Bruce wrote:

> Reading the HW-101 bulletins list, I saw the note
> regarding low output and the the IF amp tubes V3 and
> V4.  Right - power immediately jumped to
> 60W output on 10m. 

I have noted the same things happening with my HW-101. It seems that 
there are several places that tubes which you would not think would 
have anything to do with power output, definitely DO have something to 
do with it. CW power output on 80 meters with my HW-101 jumped from 
90 watts to around 120 watts with proper tubes in the proper places. I 
will post those to this list as soon as I get to my notes.

BTW, final amp tubes in the HW-101 are supposed to be limited to 
6146s or 6146As only. The 6146B or 6146W are not supposed to be 
used in that rig due to problems with neutralization.

SOMETIMES they can be made to work OK, but most of the time, they 
won't.

> I can't get the neutralization right following the
> manual, so I've got to do the alternative procedure,
> with plate and screen voltage removed.

I prefer the alternate method. It is much more accurate and the results 
appear to be more stable.

> I've got a bad socket on my tester, and I can't test
> the 6EA8's.  I also don't have any ready spares.  Has
> anyone tried subsituting a 6U8 or other potential subs
> listed for the 6EA8

You have to be careful WHERE you use those subs. The 6U8 would 
probably be OK, but it is not particulary long-lived in any place a 6EA8 
is called for.

I routinely use a 6GH8A in place of V-1, the mic amp tube, but those 
can't be used in any of the other places that a 6EA8 is used in the HW-
101 without experiencing unpredictable results. They have too much 
gain. In the mic amp, they are quite good, allowing plenty of mic gain 
with mics that would not ordinarily provide enough gain. My CW/MIC 
Level control sits at 11:00 o'clock for best audio with my mic when I use 
that tube. If I use a 6EA8 at V-1, as called for, my CW/MIC Level 
control has to be set at 3:00 o'clock or higher.

YMMV.

Ken Gordon W7EKB