>It seems that Hans knows how to keep an amp alive. My SB-220 lived for
>years and years with no problems. Keem 'em cool is the secret to long
>life for all parts.
>
However, if your tubes happen to have above average VHF amplification,
the SB-220 can occasionally oscillate at c. 110MHz. Lower VHF Q
suppressors and glitch protection helps.
cheers, Bob
>measures wrote:
>>
>> >
>> >The funny thing is that overloaded components sometimes last much longer
>> >than theory says. Look at the old SB 220: that tiny receiving type switch
in
>> >the output circuitry!
>>
>> The measured breakdown V in the SB-220 bandswitch is c. 5000V.
>>
>> > Very very soft as compared to commercial switches.
>> >That very weak 80 meter coil!
>>
>> It is #14 gauge copper with forced air cooling
>>
>> >My ex amplifier ( the very first in Sweden
>> >buit by me in 1968 -69? ) has never failed and is still in use up there
>> >above the Arctic circle with its original 3-500Zs with graphite anodes.
>> >Amazing. I always said, that one has to forget whats inside the SB 220 and
>> >look at the performance instead.
>>
>> Take a look inside and you will find forced air cooling on the tank and
>> the filament pins. This is good.
>>
>> > A very fb buy at a used price only a little
>> >bit higher than a pair of new 3-500ZGs made in France ( same as the
original
>> >tubes - the only difference is that little glass plate that lifts up the
>> >tube from the socket - less tendency for bad soldered pins to produce bad
>> >contact ).
>>
>> ''Bad solder'' results from the SB-220 cooling fan motor not turning
>> freely due to lack of lubrication. . Oiling the fan bearings every
>> couple of years will prevent this problem. . In older units without oil
>> holes, drill c. #55 oil holes above the motor shaft. Use a syringe for
>> oiling.
>> >
>> cheers, Hans
>> >----------
>> >>Från: "Steve Thompson" <rfamps@ic24.net>
>> >>Till: <amps@contesting.com>
>> >>Ämne: Re: [AMPS] " Kein Rauch ohne Feuer ...."
>> >>Datum: lör 24 jun 2000 07.17
>> >>
>> >
>> >>
>> >>
>> >>-----Original Message-----
>> >>From: N6BUU@aol.com <N6BUU@aol.com>
>> >>To: 2@vc.net <2@vc.net>; philk5pc@tyler.net <philk5pc@tyler.net>;
>> >>sm5ki@algonet.se <sm5ki@algonet.se>; n6er@yahoo.com <n6er@yahoo.com>;
>> >>amps@contesting.com <amps@contesting.com>
To: <amps@contesting.com>
>> >>Date: 23 June 2000 19:59
>> >>Subject: Re: [AMPS] " Kein Rauch ohne Feuer ...."
>> >>
>> >>
>> >>>
>> >>>In a message dated 06/23/2000 11:22:32 AM Pacific Daylight Time, 2@vcnet
>> >>>writes:
>> >>>
>> >>><<
>> >>> As long as the hv ps filter capacitors make it through the one-year
>> >>> warranty period, all is well.
>> >>>
>> >>> - Rich..., 805.386.3734, www.vcnet.com/measures.
>> >>> end
>> >>> >>
>> >>>ok rich i guess i asked for that one! i just expect "parts" to last
>> >>>somewhat longer, than the warrenty period.
>> >>> HANK
>> >>>
>> >>Treated reasonably they do this, nearly all the time. I'm sure we would
>have
>> >>heard about it here if any amp brand had a tendency to fry its PSU in less
>> >>than a few years. In truth, the reliability of raw components these days
is
>> >>excellent.
>> >>
>> >>Is there any history that amps with 'insufficient' decoupling suffer early
>> >>failure purely as a result of use on the lower bands? Is there any
evidence
>> >>that rf hurts electrolytic capacitors?
>> >>
>> >>Steve
>> >>
>> >>
>> >>--
>> >>FAQ on WWW: http://www.contesting.com/FAQ/amps
>> >>Submissions: amps@contesting.com
>> >>Administrative requests: amps-REQUEST@contesting.com
>> >>Problems: owner-amps@contesting.com
>> >>
>> >>
>> >
>> >--
>> >FAQ on WWW: http://www.contesting.com/FAQ/amps
>> >Submissions: amps@contesting.com
>> >Administrative requests: amps-REQUEST@contesting.com
>> >Problems: owner-amps@contesting.com
>> >
>> >
>>
>> - Rich..., 805.386.3734, www.vcnet.com/measures.
>> end
>>
>> --
>> FAQ on WWW: http://www.contesting.com/FAQ/amps
>> Submissions: amps@contesting.com
>> Administrative requests: amps-REQUEST@contesting.com
>> Problems: owner-amps@contesting.com
>
>
>
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
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|