Re: SB-230 tuning

Craig,
If it were me I would follow the Heath Kit instructions. I built that
amplifier in 1976, still have it. I have run it at 500 ma for many years
with it still putting out max power. I have had to replace the power supply
filter capacitors, other than than been a good 600 watts output amplifier.
While it might take a little longer to tune up, once you know what the
setting should be for a given frequency, you then can preset those and save
yourself alot of time.
Larry/W4LM

<caheaton@xxxxxxxxxxx> wrote in message
news:1151423927.624377.232040@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
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



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