Garey Barrell <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Boyd -
Well I've never noticed the bias voltage on the relay tube going up with
increased AF gain, but then I've never looked! :-)
Other things that can cause the relay to "hang" is if the ANTI-VOX is
turned up too high (might key in on AF Gain affecting bias), or if the
VOX is turned up too high, or if R106 has gone up in value. Try turning
the ANTI-VOX down all the way, and then bringing up slowly until it just
prevents tripping of VOX.
As you can see, it's a fairly high impedance circuit, so can be
difficult to troubleshoot. You should be seeing closer to -5 to -6V on
Pin 2 in receive. Depending upon your unit serial number, you might try
reducing R135 from 68k to 33k. This "stiffens" the cutoff supply and
you should see closer to -10V on PIn 2 with key-up.
I have seen a leaky cap at C205, but not likely.........
Let us know!
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B & C-Line Service Supplement CDs
<www.k4oah.com>
Boyd Van Horn wrote:
Garey, I also have a tr4-C that the relay holds in transmit. I have
done all the things you recommended. I did notice one thing. The neg
bias on the 6ev7 on the relay control side is -3.7 volts when it is in
receive. But when you increase the audio gain, the bias goes to -6.8
volts. Is this normal ? Sincerely, Boyd W0BUW
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