[AMPS] SB1000 HELP!

[Tom Rauch]

> I have a problem with an SB1000.  It works fine on all bands except
> 160m.
> I have replaced all the padding caps; 

With what?

> and passes thru the drive power of about 30 watts. I can get it to deliver
> about 200w but only if I take out the padder capacitor of 170mmf in the
> output section of the pie net, which also is needed on 80m to function
> properly. 

On what band is the 200 watts when you are driving it on 160 
meters? Where does the anode current dip or peak in grid current 
occur? Is it a clearly seen change when you pass the tank through 
resonance?

> understand the function of L9.  Can someone explain what L9 does? Is it an
> added l in the pie circuit?  I t also appears that 1/2 of L9 stays in at
> 80m,  which works just fine with the right power, Ip, Ig etc.   Thanks fer
> help.

L9 is the L section of a Pi-L.

Check the tank wiring, not the components. I suspect the tank is 
either wired wrong or you have a blown bandswitch. The SB-1000 is 
missing an anti-corona washer, plus the transformer has a bit high 
voltage under light load. That causes it to have a tendency to arc 
the 160 meter padding cap contact.

Also be sure you have smooth rounded connections in the switch 
area and the leads are kept apart as far as possible.
    
> By the way i cured the parasitics with a Measures kit which cured the
> problem.

What "parasitics"? What were the symptoms?


73, Tom W8JI
w8ji@contesting.com

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