I removed antenna, and sure enough, heard the pulsing signal at 14.0004, zero
beat at 14.0000.
The fact it’s only heard without antenna, on a frequency I never use, makes it
even more a non-issue.
73, Winston K4CWQ
Sent from my iPhone
> On Feb 26, 2021, at 8:43 PM, Carl Moreschi <n4py3@earthlink.net> wrote:
>
> You have to remove the antenna to hear the pulse at 14.0
>
> Carl Moreschi N4PY
> 127 River Moss Way
> Hertford, NC 27944
> www.n4py.com
>
>> On 2/26/2021 7:55 PM, Winston wrote:
>> After reading these posts, checked my 544. No such pulses anywhere. If they
>> only appeared at 14.0, I wouldn’t care. I never operate on band edges.
>> -de K4CWQ
>>
>> Sent from my iPhone
>>
>>>> On Feb 26, 2021, at 7:03 PM, Bob McGraw<rmcgraw@blomand.net> wrote:
>>>
>>> It is not at all unusual for electrolytic capacitors to decrease in value
>>> as they age. Thus an original 10mfd, after a few, years may effectively be
>>> a 1mfd capacitor. Although I don't care for the "shotgun" approach, this
>>> usually saves time and money.
>>>
>>> Keeps life simple and less frustrating.
>>>
>>> 73
>>>
>>> Bob, K4TAX
>>>
>>>
>>>
>>>> On 2/26/2021 10:33 AM, Mike Bryce wrote:
>>>> I’ve never done a shotgun approach when it comes to replacing electrolytic
>>>> capacitors, but in the case of this particular display unit, that was
>>>> alway the first thing I did.
>>>>
>>>> Then, and it’s been years ago, some smaller electrolytic caps (1mf) and
>>>> .001 disc took care of it. Nothing I did eliminated it 100%
>>>>
>>>>
>>>> Mike Bryce
>>>> prosolar@sssnet.com
>>>>
>>>> "The eye is always caught by the light, but shadows have more to say"
>>>>
>>>>
>>>>>> On Feb 26, 2021, at 11:20 AM, Paul Christensen<w9ac@arrl.net> wrote:
>>>>>
>>>>> Mike,
>>>>>
>>>>> Interesting. If the 544 schematic is correct, the Display Board has no
>>>>> common +Vcc. +Vcc is supplied individually to each 7-segment LED module
>>>>> via Q14-Q19 (PNP) on the Logic Board. +Vcc on the Logic board is RF
>>>>> bypassed with a 0.047uF cap at C6. +Vcc on the Logic Board is also
>>>>> connected to IC-1 with ample decoupling, consisting of a 22 ohm resistor
>>>>> and a 0.1 uF cap at C7. The 22 ohm resistor is mainly there to regulate
>>>>> current into a Zener diode that feeds +Vcc to IC-1 but it also functions
>>>>> to decouple.
>>>>>
>>>>> To me it looks like Ten Tec adequately decoupled one part of the Logic
>>>>> Board, but not the other going into the display board. The only problem
>>>>> with duplicating R/C de-coupling on the +Vcc bus feeding Q14-Q19 is that
>>>>> any series resistance will make the display slightly dimmer -- and the
>>>>> green LED segments are already way too dim due to green-wavelength
>>>>> filtering through the smoked Plexiglass lens. So, that leaves adding an
>>>>> additional RF bypass across C6 (0.047 uF). Possibly something like a 4.7
>>>>> uF 'lytic cap in parallel with a 0.22 uF film bypass will do the trick.
>>>>>
>>>> _______________________________________________
>>>> TenTec mailing list
>>>> TenTec@contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/tentec
>>>
>>> --
>>> This email has been checked for viruses by AVG.
>>> https://www.avg.com
>>>
>>>
>>> _______________________________________________
>>> TenTec mailing list
>>> TenTec@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/tentec
>>
>> _______________________________________________
>> TenTec mailing list
>> TenTec@contesting.com
>> http://lists.contesting.com/mailman/listinfo/tentec
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|