Check the bias circuit
Dave N7UE
On Mon, 17 Mar 1997 CATALANO_DENIS_E@hq.navsea.navy.mil wrote:
> I have several SB-220's which I have worked on over the years to keep
> going. I'm not an amp expert, but have fixed several. Most of the
> time, the problem is in the HV power supply. This time it's not, the
> meter shows about 3,200 V, so I have HV, and the tubes are lit. The
> problem is there is no power (0 watts) out, with 100 watts drive on
> all bands. There is continuity between the HV power supply and the
> plates of the tubes. Also, the relay appears to be working, ie. they
> click when energized, and a continuity check from the input to the
> grid caps look good when keyed by hand. One other thing, this amp
> failure was without sparks/ smoke/ fire as my other enlightening
> experiences have been. Any ideas or suggestions appreciated.
> 73 Denis W4DC (x-WD4KXB)
>
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David B. Ritchie, Esq.
D'Alessandro & Ritchie, P.C. -- Intellectual Property Lawyers
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818-683-8800 (TEL) 818-683-8900 (FAX) dbr@alumni.caltech.edu
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FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
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Problems: owner-amps@contesting.com
Sponsored by: Akorn Access, Inc. & N4VJ / K4AAA
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