Re: [Drakelist] T-4X Sidetone on Spot

2010-03-05 Thread Garey Barrell 

Curt -

OK.  Ignore my last  I was running in circles!!  :-)   Big surprise!

Anyway, I think I actually know what's going on now.  The diode switch 
D8 only keys the sidetone in CW, regardless of the position of the 
FUNCTION switch.


In the T-4X, V11 Pin 7 (Cathode) is connected directly to ground, and 
the sidetone is present whenever the key is closed, or no key is inserted.


In the T-4XB, Pin 7 is UNGROUNDED in the SPOT position of the TRANSCEIVE 
switch by a set of contacts on that switch.  THIS is what inhibits the 
CW sidetone in SPOT, but only in the B and C models.


So it looks like you're stuck with it!  :-)

Learn something new every day with this stuff.

73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 4-B, C-Line  TR-4/C Service Supplement CDs
www.k4oah.com


Hulett, Russell wrote:

Garey,

So, shouldn't D8 be reverse biased with the key UP even when the switch is in the 
SPOT position, thus silencing the sidetone?  The problem is, it is not.  That is, the 
voltage at D8 is 3 volts positive and the sidetone is whining away.

Maybe I'll just need to live with this, but using SPOT in CW mode is somewhat 
difficult because the sidetone is as loud as the spotting signal.  If that is the way it 
was designed, so be it.  My T-4XB doesn't work that way, only time it's sidetone is 
audible is when the key is down.

Thanks again, and 73, Curt KB5JO

   


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[Drakelist] T-4X Sidetone on Spot

2010-02-23 Thread Hulett, Russell 
I have a T-4X paired with an R-4.  In separate, I hear sidetone with the T-4X 
in Spot. Previous suggestion was that the electrolytic was leaky, so I 
replaced it with one from Hayseed.  The sidetone is still audible in spot.  
Does this sound like a switch problem?  Notice that the sidetone seems a little 
high pitched for my taste, but seem to recall that Drake used 1 kHz.  Also, the 
sidetone volume seems weak even with the sidetone/anti Vox full clockwise.  
Weak mic amp/sidetone oscillator?

Thanks, Curt KB5JO

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