[Premium-Rx] MM 3031A tuning question.

[w3jn]

I had the same problem in a Collins 851S-1.  I replaced the driver 
transistor inside the opto encoder and all was well.  Your mileage may 
vary.... I'd look at the quadrature waveforms at the opto encoder output and 
make sure they switch phase correctly with direction.  They probably go to a 
7486 XOR gate which determines direction... make sure all pulses are nice 
'n' square!

73, John


----- Original Message ----- 
From: "Craig Roberts" <crgrbrts at verizon.net>
To: <premium-rx at ml.skirrow.org>
Sent: Saturday, April 16, 2005 1:24 PM
Subject: [Premium-Rx] MM 3031A tuning question.


> Good afternoon all,
>
> I'm enjoying my "new" Mackay Marine 3031A and plan to spend tomorrow 
> cleaning up connectors, etc. and beginning work on my companion Class E AM 
> transmitter.
>
> My receiver is exhibiting one anomaly, however.  The opti-coupler gets 
> "confused". If I tune very slowly at any tunng rate setting, all is well. 
> But, if I rotate the tuning knob a little more quickly, the frequency will 
> move up, then down (or vice versa) at random. Is this normal? Must tuning 
> be done slowly?  I'm guessing there's a limit to how quickly the photo 
> sensors can interpret the movement of the chopper wheel..
>
>
> Thanks very much & 73,
>
> Craig
> W3CRR
>
>
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