[Amps] Tuning my SB-1000

[Lee Buller]

Let me make some points here....

Do not go over 400 mills with this amp.  The tube is rated for 400 mills, but you can do 500 mills but you will shorten the tube's life.  This tube, operated correctly, can last you 10 to 20 years.  Otherwise to replace it....$150.

Grid current should be around 120 mills.

Also, the power meter on the front is relative.  It is not accurate.  You need to invest in an outboard watt meter.

Lee - K0WA

The New Kansas QSO Party - August 29, Sat 9am-9pm and August 30 Sun 9am-3pm CDT 
 
In our day and age it seems that Common Sense is in short supply.  If you don't have any Common Sense - get some Common Sense and use it.  If you can't find any Common Sense, ask for help from somebody who has some Common Sense.  Is Common Sense divine?

--- On Wed, 3/11/09, Tom Mandera <tsm1 at tmcom.com> wrote:
From: Tom Mandera <tsm1 at tmcom.com>
Subject: [Amps] Tuning my SB-1000
To: amps at contesting.com
Date: Wednesday, March 11, 2009, 1:24 AM

Things look better after another day of research and thinking..

First, the cover came off for photos and cursory inspection, with
nothing visibly damaged.

http://www.tmcom.com/~tsm1/postnuke/index.php?module=mGallery2&g2_itemId=50718

After a bunch of pictures, the cover went back on.

Idle current, with the relay shorted but no exciter input, was the
desired 80ma.

I then tried tuning it up to 3900 on 80M (75) again.

http://www.tmcom.com/~tsm1/postnuke/index.php?module=mGallery2&g2_itemId=50718&g2_page=4

Plate wound up nearly mid point on the dial (straight up), Load at 4.3.

As indicated by the meters, with about 9/10 drive from the exciter, I
was in the neighborhood of 170ma Grid, 500ma Plate key down.

The power indicated perhaps 200w on the built in (amp) power meter,
though I'm told they're notorious liars.  I need to dig out my SWR/watt
meter and determine if it'll take 1,000w before I hook it up inline to
verify.  I didn't find any one to do an A/B test with tonight, but
perhaps tomorrow night.

No bad noises tonight, so that's a good thing.

I located two hams with a total of 5 tube testers tonight.  I haven't
placed a call yet to get some assistance with tuning the amp by someone
that knows what they're doing.  Perhaps this weekend - I need to clean
up my station a bit if I'm going to have guests over. :)

Thank you all for your assistance,

73
-Tom
KE7VUX

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