[Heathkit] Problems with HW-101 - possible fix

[Ronnie Hull]

When I built my HW101 in 1971 I put everyone of those wafers in backwards!! Had to get help tracking down my mistake. How embarrassing!!

Ronnie W5SUM

Sent from my iPhone

> On Dec 18, 2020, at 12:15 AM, Kenneth G. Gordon <kgordon2006 at frontier.com> wrote:
> 
> On 18 Dec 2020 at 5:43, jack m wrote:
> 
>> 
>> 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.
> 
> Yes, thank you, I discovered that. Also, I was wrong: all switch boards are installed correctly.
> 
> However, there is still something not quite right with the heterodyne board. According to the 
> marking on the switch-board, that wafer is supposed to have a yellow mark on it, as does the 
> crystal switch-board, but this one has an orange mark on it, and it is not faded-yellow either.
> 
> BTW, and just FYI, I am 78, and have been doing this sort of thing for many years. I worked 
> as the Electronic Instrument Specialist, Sr. at the University of Idaho for over 30 years. I also 
> have a pretty complete shop.
> 
>> It sounds like you have been tuning on parasitics all along
> 
> Not to me. I am quite familiar with what are or are not parasitics. I recently took care of 
> parasitics in an old military version of a Collins 30L-1.
> 
> This issue looks to me as though there is something physically wrong with the driver grid and 
> plate coils or their wiring.
> 
>> - 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.
> 
> According to my frequency counter, the output is exactly what it should be.
> 
>> 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.
> 
> ...as I have done with other SB/HW rigs for years, thanks.
> 
>> 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.
> 
> Thank you, Jack. You're a good fellow.
> 
> At this point, I am going to remove the driver grid and plate switch boards and go over them 
> carefully. I suspect that the original builder made an error there somewhere.
> 
> Ken W7EKB
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