[Heathkit] SB 220 on AM

Sun Sep 3 08:09:22 EDT 2006

Transformer failure! UGH!  Not surprised as the inner chassis cooling of the 
SB-220 is and has always been of questionable adequacy.  In any event, it is 
one good HF amp.  It's OK for SSB modes, CW, RTTY and AM as long as the 
"duty cycle" values are adhered to.  One area of concern with both the 
SB-220 and SB-200 is the plastic fan blades that Heath used.  They tend to 
warp and twist as a result of heat exposure.  This reduces the fan 
efficiency and resulting airflow which then exacerbates the original 
concerns as well as make them a bit more noisy due to vibrations.   I 
replaced the original 4 blade plastic assembly in mine with a 6 blade metal 
version obtained from Granger.  More air and less noise.

73
Bob, K4TAX

----- Original Message ----- 
From: "Peter Markavage" <manualman at juno.com>
To: <heathkit at mailman.qth.net>
Sent: Saturday, September 02, 2006 11:18 PM
Subject: Re: [Heathkit] SB 220 on AM

> The nice thing about SB-220's is that there are tons of them around. You
> could always find one and just dedicate it for AM operation.
>
> I've been using a SB-200 on AM with the original 572's (put in 1969)
> since about 1985 and I still use it on SSB. I've driven the SB-200 with
> Rangers, Icom's, Kenwood's, Central Electronics, and even a Lafayette rig
> all on AM. Still has original caps, diodes, and noisy fan. These rigs are
> hard to kill.
>
> Pete, wa2cwa
>
> On Sun, 03 Sep 2006 00:02:21 -0400 Jim Brannigan <jbrannig at optonline.net>
> writes:
>> Duane,
>> I was not the original builder of my SB-220.  I bought it over 20
>> years ago
>> from a fellow who bought an Alpha and needed the money. (and
>> regretted the
>> purchase)
>> A few years after I purchased it the transformer blew (in the middle
>> of a DX
>> contest), fortunately, Heath was still in business and I was able to
>> get a
>> new replacement.
>> It has Harbach capacitors, fan and soft start, "Silicon Alley"
>> rectifiers,
>> Rich Measures parasitic suppressors and a timed relay start-up.
>> In the early 90's The SB-220 and an S-line won the NLI section in
>> the ARRL
>> CW DX contest two years running.
>> These days it works great with a TT OMNI-VI+ trying to keep me on
>> the Honor
>> Roll.
>> For the money it is the best amplifier, bar none. I've tried for
>> years to
>> talk myself into a "better" amplifier, but it doesn't add up.
>>
>> With all this history I am very reluctant to over-stress my old
>> friend on
>> AM.
>>
>> 73,
>> Jim
>> PS: it has the original finals, but they are getting a bit soft
>>
>>
>>
>> > Suck it up James! The Heathkit SB-220 is a decent HF amplifier, a
>> real
>> > work horse in fact. So unless the former owner/owners assembled
>> her
>> > incorrectly you should be as happy doing eons worth of DX bank
>> shots off
>> > the D layer of the ionosphere as Ben Franklin was after that solid
>> Brass
>> > key he was holding between his wet lips evolved into the dance
>> step of the
>> > century that historic electron Cha Cha, Proton puddle piddle and
>> neurotic
>> > Neutron necromancy when that inspired bolt of wisdom from the
>> great blue
>> > beyond ignighted his mustache, abundance of 12 gauge nose hairs
>> and bushy
>> > eyebrows transforming his bifocal parking place into what put one
>> in mind
>> > of a seriously char burned super sized marshmellow! So Jim should
>> a
>> > 'Headless Horseman' pull up in a horseless carriage and deliver
>> into your
>> > trembling hands an envelope bearing your Colonial family monogram.
>> Easily
>> > verified as an authentic manual, bold sprawling script listing
>> slightly to
>> > starboard from Peter The Scholar of Schematics, the Master of
>> manuals and
>> > Lord Laffayette the only guy in Benton Harbor, Michigan who could
>>
>> > seamlessly solder up a sword shank withouta cold shoulder joint!
>> >
>> > James, this final tidbit that I trust will help you distinguish
>> the
>> > properly assembled Heathkit from one that really should be used to
>> anchor
>> > a boat! If when you remove the bottom plate that covered the
>> inside of the
>> > chassis, turn it back rightside up and observe what gifts befall
>> you. The
>> > General class rule of thumb is, assuming you still have said
>> digit, having
>> > niether burned it off due to poor soldering iron habits or slipped
>> with a
>> > razor blade knife and whittled flesh and bone into a living
>> toothpick, if
>> > you can fill the Anthrancite Coal car of a 1952 Tom Thumb 1/50
>> scale model
>> > with loose solder, don't buy it! Because some kit clutz kid, or
>> Bozo The
>> > Clown drop out, lived in a joint with no heat and a lot of cold
>> solder!
>> >
>> > If you should need them Jim, I still retain copies of the original
>>
>> > assembly and service information manuals. A great amp, 'provided'
>> you DO
>> > NOT overdrive it. If you let her run about 800 watts keydown and
>> watch the
>> > grid current, the 3-500Z's can last twenty years. According to a
>> note from
>> > Jim H., he was still using the original finals he put in his
>> SB-220 in the
>> > early seventies.
>> >
>> > If you need "good" quality original, or reproduction, manuals then
>> utilize
>> > WA2CWA, Pete or NI4Q, Al Bernard. Excellent detail, sharp
>> contrast, well
>> > bound, reasonable prices and prompt shipping. Two gentlemen! There
>> are
>> > others who also do nice work, but Pete and Al get the old blind
>> dude's
>> > "thumb and a third" up! (LOL!)
>> >
>> > Duane Fischer, W8DBF
>>
>> _______________________________________________
>> List Administrator: Duane Fischer, W8DBF
>> ** For Assistance: dfischer at usol.com **
>> $$ See the vintage area on the HCI web site - http://www.w9wze.org
>> $$
>> Heathkit mailing list
>> Heathkit at mailman.qth.net
>> http://mailman.qth.net/mailman/listinfo/heathkit
>>
>>
>
>
> ManualMan, now has available laminated credit card style "Quick Reference
> Guides" and laminated "Mini-Manuals" for many of the current Icom,
> Kenwood, and Yaesu HT's,mobiles, and HF rigs. Newly introduced heavy
> steel HT stands are now available.
> _______________________________________________
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
> $$ See the vintage area on the HCI web site - http://www.w9wze.org $$
> Heathkit mailing list
> Heathkit at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/heathkit
> 