[Amps] Alpha 76CA Operation

[VO1HP]

I am helping a friend check out an Alpha 76CA  ser # 69XX.   I wonder if 
anyone can tell me  what the typical CW output power should be for 700ma 
plate current and  grid current in the 70ma range.    We notice that 
while testing on 160M that the grid current will flop around a bit  up 
down around the above figure.     The amp has been in storage for about 
20 years.  We reseated the tubes and the various molex connectors.

The amp tunes normally but the output seems low?     On 160M we see 
about 700-800W and on 20M about 500W at above noted plate and grid 
currents.

Amp is plugged into 120VAC line.

73 Frank VO1HP
St.John's NL