[Amps] Soft 8877???

[R.Measures]

>Hello All,
>
>A quick newbie question. 
>I recently picked up an old Henry 3K X
>that had sat unused for the last 17 years.
>This is the version with the 8877.
>This is my first 8877 based amp and I'm seeing
>some odd behavior:
>
>Max power out 700W. (from what I understand
>I should be getting 3X that.)
>Virtually no grid current.
>Plate voltage looks ok, 4000V in SSB 3000V in CW mode. However, the output 
>does not change from one plate voltage to another. Just seems to hover 
>around 
>500-700W. I have tried driving it to 900mA on the plate
>and 400mA on the plate, observed some difference but
>not much, maybe 25% difference. 
>
>Any ideas? At first I thought it might be the tuning circuits 

If the P-out is ok on the lowest band, there could be a problem with the 
bandswitch's L-contacts.  If the 40m L-contact is intact and the P-out on 
80m and 160m is low, the problem could be in the Tune-padder bandswitch 
contacts for 80 and 40.  
--  The 8877 should be checked with a hi-pot at 8kV to see if any gold 
has left the grid.  (this condition can usually be ameliorated)

>but I'm not 
>sure. Or, is it the tube? Seems to me that if I can pull 900mA through the 
>plate then the tube may not be bad...
>
>73,
>
>Paul N1PA
>
>
>
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