[Heathkit] Problems with HW-101 - possible fix

[jack m]

Ken,

Review the manual again with respect to the wafer notches - They are all supposed to be in the same direction except for the heterodyne board - it is 180 out.  All this has to match up with the proper indexing on both the front panel index/stop, and the rear cage shaft stop.  Take your time, and don't push the shaft against the wafer rotor too hard while lining these up or you will be looking for a donor board(s).  Just kind of ease the shaft in to each wafer using the knob on the shaft for controlled leverage while wiggling and while watching with the cover off, of course.  The rotors tend to float somewhat.

It sounds like you have been tuning on parasitics all along - these do strange things, and I have never seen one specific symptom repeat itself on a different rig exactly the same way.  A way to test for the parasitics is to pull V6, and see if it stays at power out.  If it does stay, all the drive energy is initiating in V7.  There is a 50-50 chance the drive control has any impact on the output level with the parasitic present.  Be sure to have the tube shields on V6 and V7, and the coil cover in place.  Verify for a good ground on the tube socket for V7 shield - bend the tab, and scrape the shield if needed.  Substitute a known good 6CL6 into V7 to see what changes.  Again, monitor the frequency you hope to be transmitting on.

With everything all lined up, I'll wager that you get good coil peaks on each band.  Just be sure to preset the preselector to 12 o'clock for 80-40-20, 2 o'clock for 15 and 2:30 o' clock for 10 on the 29.0 range.  Make sure the O-ring belt are pliable and tight, or you may never be able to sync the variable capacitors.  Go through the sequence twice - with the last time at about 1/4 - 1/3 power to get nice clean peaks on transmit for the driver grid and plate coils.

If you have a frequency counter, probe V6-1 to see the actual crystal frequency you are working with for each band.  Each one should be close to xx.395 or xx.895.  If these are close, then check your cal signal to see how far off the LMO dial "0" point is.  You can make minimal shifts using the het osc coils, but do not go much above -2.0 volts for any given coil.  To make a convenient test point, I usually insert a #3-42x3/4" round head screw from the bottom side of the board into the test point hole, solder it to the land and this provides a robust point for an alligator clip topside when compared to the bare wire originally placed there.

Jack  W3RU

________________________________
From: Kenneth G. Gordon <kgordon2006 at frontier.com>
Sent: Thursday, December 17, 2020 10:18 PM
To: heathkit at mailman.qth.net <heathkit at mailman.qth.net>; jack m <oldvette at hotmail.com>
Subject: Re: [Heathkit] Problems with HW-101 - possible fix

On 18 Dec 2020 at 1:25, jack m wrote:

>
> Ken, common experiences with the 10x series!  Here is what I have found in my numerous restorations:  (suggestions in CAPS for easy interspersed reading - I'm not shouting).
> ------------------------------
>
>
> Then, when I attempted it align the rig, following the manual's
> directions, I found that I could not find any peak on either the grid or
> the plate coils for the driver on 10 or 15 meters, and the peaks on 40 and
> 20 were weak, probably due to the fact that all those coils are in a series-parallel
> arrangement..
>
> CHECK THE WAFER FINGERS FOR CONTACT, AND VERIFY THE ROTOR IS NOT 180
> DEGREES OUT OF PHASE (CHECK THE NOTCHES WITH THE BANDSWITCH SHAFT
> OUT).

Thanks, Jack, for this suggestion.

Upon checking the notches, only two out of the five wafers were correctly installed: only the
wafer for the final tank coil and that for the heterodyne oscillator crystals was correct: all
others are completely backwards, or 180 degrees wrong.

What THAT brings up is why, then do 80, 40, and (sort of) 20 still work?

Even so, I'll correct those and then see what problems I have left.

Thank you very much for the suggestions.

Ken W7EKB