Curt -
Nothing wrong with an Omni VII 'frequency counter'! A lot more
sensitive than any 'real' frequency counter and more than adequate for
our needs.
Depending upon what tube tester you have, you could sell it and put the
money towards a good scope. Only one or maybe two of the Heathkit
scopes is worth the trouble. You can get a GOOD Tektronix 454A, 465B,
2215A, etc. for $150. Unless they have been mistreated, they'll most
likely outlast you without service. There is nothing so useful as a
_calibrated_ (both voltage and time), 'triggered sweep' scope for
troubleshooting just about any electronic equipment. With a scope and a
VTVM you can fix just about anything, and make a good stab at
alignment. A signal generator is nice, but something as simple as an
Elecraft XG-2, in combination with a receiver's calibrator, will do 90%
or more of what you NEED.
Contrary to popular belief, we really DON'T need to measure voltages to
three decimal places or frequencies to six.!!
If your 4 Line is working, you can do a perfectly competent alignment
with nothing more than a 'voltmeter' and the internal calibrator, and be
within 5% or better of 'optimum'.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-B, C-Line&
TR-4/C Service Supplement CDs
<www.k4oah.com>
Curt wrote:
For someone who doesn't own all the requisite test equipment, it
would be nice to know of competent folks in the area capable and
willing to properly align Drake gear. I'd happily pay someone to go
through my 4-line, but am not interested in shipping it anywhere.
My "frequency counter" is my Omni VII, besides that an old Eico signal
generator, VTVM, capacitance bridge, and tube tester. Am afraid
buying an old scope would just add another piece of equipment needing
to be worked on.
----- Original Message ----- From: "Garey Barrell" <k4...@mindspring.com>
To: <drakelist@zerobeat.net>
Sent: Wednesday, December 01, 2010 12:40 PM
Subject: Re: [Drakelist] TR-3 Saga
Tom -
Repairing stuff is so much more fun when you have the proper test
equipment! :-)
The manual procedure only works if the radio has not been 'repaired'
by someone else! What probably happened in your case was that the 9
MHz oscillator was 'outside' the sideband filters rather than in the
valley between them. Once that happens it's tricky to get it back
without a counter.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-B, C-Line&
TR-4/C Service Supplement CDs
<www.k4oah.com>
pony...@aol.com wrote:
Hi gang, you too Ron,
Had a lot of fun last night. I took my TR-3 over to Terry's last
night. We found no bad components, just awfully bad alignment. It
was impossible to set the 9 Mhz oscillator the way the book calls
for, so we set it with a frequency counter, then went through the
entire alignment procedure using a scope, rather than my tin ears,
surprisingly everything lined up perfectly. The last thing we did
was to set the 9 Mhz oscillator to line up with the band pass of the
crystal lattice sideband filter. We did this with the scope,
flipping back and forth with the sideband switch while transmitting
an audio signal, adjusting the crystal frequency until both upper,
and lower sideband signals were equal.
Thanks for all your helpful thoughts...... enjoy those
Drakes............Tom Maguire, WD8JPP
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