[Amps] sb-220 questions

[Dan Sawyer]

All, follow-up;

The 100 ma idle plate current is on low power. It is 140 ma on high 
power; so the "idle" state seems ok.

However the amp defiantly will not put out full power. Grid current 
'hockey sticks" high at about 25 watts drive putting out about 500 watts 
and with no additional output power.

1. 80 and 40 meters do not seem to tune well. The 'tune' cap is near 
fully engaged. These bands "hockey stick" grid current at about 400 
watts out on 20 watts drive. How can I test to determine is they are 
properly tuned with the 'tune' control at a maximum??

2. 20 and 15 meters tune up nicely and put out about 600 watts before 
they hockey stick grid current at about 25 watts drive.

3. 10 meters is weak, it only puts out about 200 watts.

Is this simply really weak tubes or is there something else wrong??

Thanks,
Dan

Steven Grant, W4IIV wrote:

> should have 150 ma with no drive...tho 100 is ok i reccon...may be a 
> tad low
> steven  W4IIV
> */Dan Sawyer <dansawyer at earthlink.net>/* wrote:
>
>     All,
>
>     I just picked up an sb-220 and it is not behaving 'properly'.
>
>     It draws about 100 ma of plate current with no input, just the relay
>     closed. Is this normal??
>
>     It behaves predictably up to about 20 watts of input. It develops
>     about
>     20 to 1 gain from 1 watt in to about 20 watts in. At about 20 watts
>     input there does not appear to be any additional power out and both
>     plate and grid current rise sharply. Is this weak tubes or
>     something else??
>
>     Thanks,
>     Dan
>
>
>
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> STEVEN GRANT W4IIV
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