Ben:
Good points. Especially the one "Moreover, if you dont understand the above
procedure, dont do it. I will not be responsible for any calamitous results
if for some reason you interpret the above as a go ahead to tweak every
thing and or the wrong thing. The voltages are not dc volts and no amount
of hoping your vom will read correctly will make it so."
Comes under my statement "if it don't need tweaking........don't tweak it".
73
Bob, K4TAX
----- Original Message -----
From: "Ben K8DIT" <benk8dit@serv.net>
To: "Adam Farson" <farson@shaw.ca>; "Ten-Tec Contesting"
<tentec@contesting.com>
Sent: Monday, September 30, 2002 8:55 PM
Subject: Re: [TenTec] Omni VI Plus freq. readout
> The readout on the Omni 6 can be straightened out by measuring the voltage
> at the test point just off of the signal charge pump transistors on the
> Logic Board schematic.
> The voltage test point is just below the ADSP 2105 chip on the schematic.
> Q's 3,4,5, and 6 are the signal charge pump. By adjusting the inductors as
> you switch thru the bands, on the L.O. mixer board, and adusting the
output
> to 2volts, at that test point, you have brought the phase locked loop and
> the crystal subband locking systems into its designed synch, hence an
> accurate readout. Now this procedure can be pretty confusing if you tweak
> the wrong inductor for a given band, you must begin over again. Care must
be
> taken because the inductors are not ascending in the lineup. If you
measure
> 2volts plus or minus 1 volt, there is no need to adjust the inductor on
the
> L.O. board for that band. If the readout is still off, or if the voltage
> skips around on a particular band, then suspect that the crystal has
> migrated/aged out of tolerance and must be replaced. A little coolant to
> that crystal will tell the tale. My shchematic says 2v right next to r13
on
> the 81606 circuit board which is the Logic Board.
> Moreover, if you dont understand the above procedure, dont do it. I will
not
> be responsible for any calamitous results if for some reason you interpret
> the above as a go ahead to tweak every thing and or the wrong thing. The
> voltages are not dc volts and no amount of hoping your vom will read
> correctly will make it so.
> My friend who has lab quality test equipment did this procedure and found
> faulty crystals and a failed chip. Both times the above procedure was done
> at the end and my Omni has been accurate to 2-3 hertz for the last year or
> so. I had noticed that my problems began with the readout being 50 hertz
> off, and then worsening with time.
> My radio is 1995 vintage and before I bought it, two previous owners sent
it
> in for a thorough going over. So over time as use shakes out the weak
> components, its nice to know that not very much can go wrong if you keep
up
> with the problems. Ive owned it since Nov. 2000.
>
>
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