[Heathkit] The HW-16: Is that my final answer?

[Thomas Qualtieri]

Well here is anothe vote for your fix tried it on my HW-16 Project and it 
cleand that hum right up and now the radio is working great !!

>From: Tom NØJMY - AAR7FV <tfarl at mchsi.com>
>To: "glowbugs" <glowbugs at piobaire.mines.uidaho.edu>
>CC: heathkit at mailman.qth.net
>Subject: [Heathkit] The HW-16: Is that my final answer?
>Date: Thu, 3 Mar 2005 22:28:08 -0600
>
>In the saga of  my continuing quest to understand what makes HW-16's hum at 
>idle, the problem turned out to be...Lord only knows.  I substituted 
>another 6HF8, tried all the suggestions from everyone on these lists, even 
>checked for heater-cathode leakage in the final (found a note that N2EY 
>wrote where that can be a problem.)  I also RE-recapped the P.S. with 
>radial-lead caps (2-100 uf, 4-82 uf, and a couple 47 uf on the bias supply) 
>to get the leads down to a bare minimum.  Plus, I loosened, then tightened 
>every screw and nut, re-heated every solder joint I could reach, and 
>corrected the out-of-spec bias voltages.  Hummmmmmm.  Just like 90% of the 
>HW-16's I've had.  Maybe I'm being overly picky with this cochlear implant! 
>  Again, this is the phenomena where the hum is audible only with the AF 
>gain at minimum, then it drops off and disappears at about half-throttle.
>
>So, I utilized the fix I had settled on originally and bypassed the audio 
>power-amp grid with .01 uf cap.  Now she's as quiet as can be. Plenty of 
>gain, though.
>
>The best part is, I had her on 80 and 40 tonight with my inverted-vee, and 
>worked Ohio, Arizona and Oregon, receiving a clean bill of health as far as 
>chirp, click, or yoops from each one in turn.  I specifically questioned 
>each one on these subjects.  Of course, it's not official until I work a 
>couple of you guys that I know will be brutally honest with me hi HI.
>
>BTW, I was rock bound and did not use the Pierce oscillator capacitor mod.  
>I guess even a blind hog finds an acorn, now and then.
>
>I'll check it out on 15 tomorrow, then I'll see if I can work some of you 
>guys over the weekend.  Every has to be ship-shape when I ship it out to 
>Jerry, N5KYE, on Monday.  BTW, many thanks to Jim, W5JO, for sending Jerry 
>to me.
>
>Glad to see NR5A is going to recap his.  That should make all the 
>difference. I'm keeping my fingers crossed.
>
>73,
>Tom
>
>
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