[ARC5] BC-454-B Dymamotor Question

[Christopher Bowne]

I have had a similar buzz pop up on my CW note from time to time when using my 
BC456/DM-33 powered T19 ARC-5.  Makes the signal sound like a rotary gap spark 
transmitter.  Goes away when I give the dyno a what the Navy calls a strong 
"mechanical agitation".  I have actually seen that term in a system operating 
instruction (OI). "...if neccessary, mechanically agitate valve X...".  In the 
case of the dyno, one of the commutator brushes hangs up, probably due to 
excessive wear causing binding in the retainer slot, and/or a weak tensioner 
spring.  Check your dyno brushes and commutator condition.  


From: Mark K3MSB <mark.k3msb at gmail.com>To: ARC5 <arc5 at mailman.qth.net>


Sent: Thu, January 17, 2013 7:39:46 PM
Subject: [ARC5] BC-454-B Dymamotor Question

When using the dynamotor on the BC-454-B, there's a constant loud buzz in
the audio that I would think is coming from the dynamotor as it sounds like
a motor sound.   I tried both dynamotors in the radio and one seems a lot
less pronounced, but still strong.

I then wired in separate 250V and 28V supplies (non dynamotor) and the
receive audio is great.

Is what I'm hearing with the dynamotors normal?

73 Mark K3MSB
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