I'd like to add one item to Dave's post below for caheaton's benefit:

If you don't have a 50-52 ohm dummy load (pure resistance, dry or oil,
whatever, but with capability to handle 100-200 watts of dissipation for
at least as long as you will be spinning those knobs), please get one.
And, learn how that amplifier tunes up going into a known, low SWR dummy
load (your SWR meter is between the transceiver and the amp). Your antenna
tunner (which is between the amp and the antenna feedline) shoud be tuned
up for low SWR _BEFORE_ you turn on the amp. After you know the SWR is
low, then turn on the amp and drive it with, say, that 20 watts of
carrier, or with the microphone gain turned down. Once you are statisfied
that the SWR is low with/without the amp in the circuit, then you can
crank up either the carrier (alone) for touch-up tuning, or crank up the
audio gain (and watch the room lights flicker, etc).

And, I'll go along with the recommendation below to do the tune up pretty
fast.

===== no change to below, included for reference and context =====

On Wed, 28 Jun 2006, Dave Edwards wrote:

Craig...At one time I had 4 SB230's
Now I have one on hf, and one converted to 6 meters.
Either tune by the book, or tune for maximum output....either way, just do
it fast.
The only big mistake to your steps I can see is not to start at 80
watts....that is close to full drive.
I would say to start at around 20 watts.
Make SURE the SWR that the amp sees is reasonable. ...less than 1.8:1 or
so....If you have a tuner in that path, make sure it can handle the
power....nothing MFJ!!!

Key down your rig while watching the amps' RF output and spin the plate knob
quickly each way to find a 'kick' or peak in output. At 20 watts drive, I'd
expect 150 or so watts out. Stop transmitting, and wait 5 or 10 seconds. Now
is the part that you only learn from experiance....it'd be nice if you were
doing it with a TS520's 6146 final....instead of an unobtanium
8873....But....
you need to transmit, and tune the load control while simultaneously
juggling the plate control. All the while looking at the wattmeter for more
output. At some point, rotating the load and peaking with the plate will
NOT end up in more output. That is where you stop.
Now you can increase power from the rig to whatever you want...but the load
and plate will have to be 'touched up' again with the increased drive.
Pulsers are kind of a waste. Someone who has used an amp for a while should
be able to tune it up in 2 or 3 three second transmissions. If you are
playing with knobs while key down for 15 to 20 seconds, you shouldn't own an
amp!!
...Dave


wrote in message
oups.com...
First, my thank you's are in order to all who have answered my posts
concerning this amplifier...I have not yet fired it up, but I'm getting
there! (Taking it easy and following the good advice I've received).
Anyway, I've browsed the Heathkit manual and their instructions for
tuning the amp seem rather complicated....they tend to focus on tuning
for output and very specific plate and grid currents. Would it be safe
for me to instead use the following procedure (which is likely to get
me to the same point, but is easier to remember....it's the technique
we used t for the old club amplifier):

1) Turn on amplifier (of course) and allow it to warm up.
2) Set exciter for 80 watts output on cw (amp is supposed to take 100
watts, but I want to be on the safe side).
3) Set pulsed tuner aid so that I am running about a 25% duty cycle
(average power into amp will be 80 watts peak, but only 20 watts
average).
4) Set amp tune and plate controls to suggested starting points.
5) Switch amp out of bypass.
6) Tune amp "Load" for max power out, adjust "Tune" to dip plate
current, check grid and plate currents.
7) Increase pulsed exciter power gradually while repeating step 6.
7) Repeat step 7 until desired power out is achieved (keeping in mind
that I need to stay well within allowed grid and plate currents).


In a nutshell, that's how I remember tuning our club amp (although it
was near 20 years ago when I last tuned one.) Does this sound about
right? It seems much faster than the steps outlined by Heathkit and
safer too...also, would there be any problems with my signal if I keep
the exciter power fairly low...say at around 50 to 80 watts rather than
the 100 watts specified? (Granted, my output power will be lower, but
that is fine...especially while I'm still just testing the amp and if
any RFI will be generated by the amp.)
Thanks a bunch!
Craig KB8FGC