[Kenwood] TR-7730 TX off freq.

[fredv]

Hi Ed

Well, what was supposed to be a fun job fixing this rig today has
been temporarily put on hold as my trusty Tek 7904A scope
died today. It just happens to also be my freq counter (a plug-
in). Now I have to fix that.

But anyway, I looked at the circuit and I see only two
crystals with trimmers. A 42.6mhz Rx and a 46.1666mhz Tx in the
PLL section. There is also a 10.24Mhz crystal in another section of
the PLL, and a 10.245Mhz crystal in the rx/tx unit. I has just finished
checking the 10.245 one when the scope went out. It was ok.
I put a copy of the block diagram up at
http://www.qsl.net/n1dec/files/7730blk.JPG if
you care to see.
Thanks for your help. By the way, the Azden rig you helped me with
once still works great!

Fred
N1DEC

----- Original Message -----
From: <ma.locksmith@juno.com>
To: <fredvp@snet.net>
Sent: Friday, August 09, 2002 3:00 PM
Subject: Re: [Kenwood] TR-7730 TX off freq.


> Some sets, and I don't have the schematic for yours, generate the
> transmit frequency by mixing the receive LO and a crystal oscillator
at
> the IF frequency.
>
> In this way, they can keep the PLL/VCO the same for transmit and
receive.
>
> If this is the circuitry in yours, you ought to be able to adjust this
> oscillator with a trimmer.
>
> Ed Lambert
>
>
> On Fri, 9 Aug 2002 13:24:58 -0400 "fredv" <fredvp@snet.net> writes:
> > Hi
> >
> > I just was informed that my old TR-7730 2m mobile
> > rig is off freq.
> > Well, after my tests, it seems it is in fact off freq on
> > transmit by almost exactly 5khz too low.
> > Rx seems ok.
> > Does anyone have any ideas on this problem?
> > I have the schematics here.
> >
> > Thanks,
> > Fred
> > N1DEC
> >
> >
>
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