[Amps] How to tune an FL-2100B

[R L Measures]

On Jul 4, 2006, at 4:02 AM, Dan Wright wrote:

>
> Greetings!!
>
> I am new to this list, but not too awfully new to amateur radio,
> been licensed 42 years....but maybe that don't mean much!
>
> I have a recently acquired Yaesu FL-2100B. I have never owned
> one of these, but I have several other amps.
>
> Anyhoo....the second time I used it, the bandswitch arced and
> burnt to a crisp! Maybe I'm not tuning it up properly?

An arcing bandswitch in a 2100B is usually the result of regeneration  
roughly 95MHz.  If you want to see the resonance that supports this  
phenomenon, pull the power plug and couple a dip-meter to either end  
of the DC blocker cap.  You should see a sharp, high-Q dip where its  
taking off.  To make the amplifier have less gain / more stability at  
VHF, decrease the VHF-Q of the parasitic suppressors.
   Burned bandswitch contacts can sometimes be replaced by drilling  
out the rivet and fastening another contact in it's place with #0-80  
brass hardware.
    cheers, Dan
>
> My desire is to use it on 40 meter AM.....yep! AM!!! I want
> to run about 150-175 watts of carrier, driving the amp with an
> FT-101EX through a Dentron MT-3000A to a W9INN dipole (which
> is resonant on 7290).
>
> How do I do this without burning up the bandswitch again,
> assuming it was my fault in the first place???
>
> Thanks es
>
> 73 de Dan -- WA0JRD ..
>
>
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R L MEASURES, AG6K. 805-386-3734
r at somis.org