[ARC5] BC-454-B Dymamotor Question Part 2

[J. Forster]

If you are seeing <50 mV on 250 VDC, you are doing fine, IMO.

-John

==============


 Gang –
>
>
>
> Well, I think it's been around a week and a half since I lasted posted on
> my "saga",  but I did find some time on Saturday to rebuild my DM-32A for
> my T-19.  I lubricated as per the manual and the work went OK.
>
>
>
> Tonight I took some measurements.   There's still "hum" on the audio, but
> I
> think it's a bit better.  Here’s some pictures of the new waveforms.
> These
> were taken by using a voltage divider (10K, 100K) into my scope,   and
> taping off the socket upon which the dynamotor sits in the radio.
>
>
>
> Picture 2858:
>
> www.k3msb.com/temp/100_2858.jpg
>
>
>
> 40 mV P-P (scope at 20 mV / division)
>
> Period of 9 mS (scope at 5 mS / division) which is 111.1 Hz.
>
> Input voltage is 2.2 VDC from the divider, or 24.4  VDC into the radio.
>
>
>
> Picture 2860:
>
> www.k3msb.com/temp/100_2860.jpg
>
>
>
> 40 mV P-P  (scope at 20 mV / division)
>
> Period of 9 mS (scope at 2 mS / division) which is 111.1 Hz.
>
> Input voltage is 2.2 VDC from the divider, or 24.4  VDC into the radio.
>
>
>
> Is this what’s it’s supposed to look like?
>
>
>
> Raw input from my 28V supply (again, using my voltage divider)
>
> Picture 2852:
>
> www.k3msb.com/temp/100_2852.jpg
>
>
>
> 1 mV P-P  (scope at 1 mV/division)
>
> Period about 17 mS (scope at 5 mS/division)  which is about 60 Hz.
>
> Ripple is 1 mV from divider, or about 11 mV P-P (which is OK).
>
>
>
>
>
> Now, here’s two pictures of the audio output (minimum gain), no voltage
> divider used.
>
>
>
> Picture 2864:
>
> www.k3msb.com/temp/100_2864.jpg
>
>
>
> 30 mV P-P (scope at 10 mV/division)
>
> Period about 5 mS (scope at 5 mS/division) which is about 200 Hz.
>
>
>
> Picture 2867:
>
> This 2nd picture is when I’m applying pressure to hold the dynamotor down!
>
>
>
> www.k3msb.com/temp/100_2867.jpg
>
> 20 mV P-P  (scope at 10 mV/division)
>
> Period about 5 mS (scope at 5 mS/division)  which is about 200 Hz.
>
>
> Again, is this what I should be expecting from a dynamotor powered T-19 ?
>
>
> 73 Mark K3MSB
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