[TenTec] Centaur amp

[phil greene]

New to me Centaur amp with 572 tubes of unknown health. 
Only has output on 80 meters (~500w)
10-40 meters have plate and grid current but no output
Load capacitor has no effect on any band
Tuning cap will dip grid current
Tried dummy load with same result 
All resistors check good, and have cleaned band switch and it did not appear cracked nor damaged. 
Ideas on where to start troubleshooting?
N4ZSA


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