[Heathkit] HW100/101 curiosity

[Bwana Bob]

Dick:

If the peak on the driver tuning is erratic, it means that the driver 
stage needs to be neutralized.  A squeal, coming from the final, not the 
speaker, is a parasitic oscillation, requiring final neutralization.  If 
the squeal comes from the speaker, spray the relay contacts with contact 
cleaner. Sometimes there is a carbon buildup on the contacts which will 
result in incomplete muting.

                     73,

                     Bob WB2VUF

On 5/24/2012 7:15 PM, Dick KF4NS wrote:
> Ok guys, sure sounds reasonable. Thanks to all for your input. While I am at it, after the problems and
> restoration are now complete, I notice that frequently there is a strange squeal or screech coming from
> the speaker while on the dummy load during tune-up. Everything is tied down tight and over the past 40+
> years I never heard this before. It must be an oscillation of some sort but am going to try a suggestion
> in the manual regarding the driver neutralizing wire but it relates to jumpy tuning; still could be a
> possibility. I am sure I must have moved that wire at some point during the repairs. The finals are not
> yet neutralized but are the original ones from before the crash (6293s added in 2003). Well, we will see.
> 73, Dick KF4NS
> St Petersburg, FL 33714 USA
> Keep The Glow!
>
> ----- Original Message -----
> From: "Bwana Bob"<wb2vuf at verizon.net>
> To: "Dick KF4NS"<kf4nsradio at verizon.net>
> Cc: "Heath puck list"<heath at puck.nether.net>;<heathkit at mailman.qth.net>
> Sent: Wednesday, May 23, 2012 10:26 PM
> Subject: Re: [Heathkit] HW100/101 curiosity
>
>
> | Dick:
> |
> | Well, this is my opinion:
> |
> | Tuning the het osc coils in receive mode  gets you in the ballpark, so
> | the receive tuning is preliminary. The tuning for maximum transmitter
> | output is more critical. Just tuning on receive will not maximize
> | transmitter output.  Just tuning on transmit, one might miss the peak
> | entirely.
> |
> | Even though the jumpers between the finals are short, they do have some
> | inductance. Heath probably wanted to keep the impedance to ground very
> | low so as to prevent the jumper inductance from causing parasitic
> | oscillations in the final.
> |
> | Bob WB2VUF
> |
> | On 5/23/2012 8:15 PM, Dick KF4NS wrote:
> |>  Hi guys,
> |>
> |>  A couple things have always bugged me so I will ask the questions now and see what I can determine.
> |>
> |>  In the alignment, I have always wondered why, after all the time spent adjusting the HET. OSC. coils
> to
> |>  the spec, why do we need to start all over again when we do the transmit alignment ??
> |>
> |>  Also, in the finals, pins 1, 4 and 6 are tied together between the two tubes, so why the redundancy
> with
> |>  three .005 mfd bypass caps on each tube? Would it not be just fine to have only one cap for both
> tubes
> |>  instead of six caps ?  The tube spacing is so close I see no need for the multiple caps.
> |>
> |>  73, Dick KF4NS
> |>  St Petersburg, FL 33714 USA
> |>  Keep The Glow!
> |>
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