[SBE] Continental 816

[Barry Thomas]

I haven't seen much activity on this list in a long time. I hope the brain trust is still active. 

It has been soooo long since I've troubleshot a Continental 816 with a tube driver stage i really don't remember the old skill set.  Some advice on the first things to look at would be great. 

The problem:  I am not getting enough power out of the transmitter .... Only 80% with it running at full blast.  The final is new and good and tunes well. 

I'm fairly certain it's driver-related. 
At first I thought it was just bad 4cx250b tubes...They were old.  I Replaced them but still have the same results. Both tubes are operating and seem balanced.  I've got a good match from the exciter into the driver stage and the driver plate tunes into the final, although PA grid current is low (of course). 

Driver and PA Plate and screen voltages are fine. Cathode currents of the two drivers are balanced but low. In fact All driver current readings are low by 50-70% EXCEPT driver screen current reading which is PEGGED.  Backing off the power to 40% final output un-pegs the meter but it is still at the max scale. I know I should remember exactly what this means but it has just been too long.  Or maybe the meds have killed too many brain cells. 

I am hoping with your help I can short circuit some of my re-education on this old box. 

Any suggestions on the FIRST things I should check in the driver stage?  

Thanks for your suggestions. 

Barry Thomas, CPBE DRB CBNE

Sent from my iPhone 5


Barry Thomas, CPBE DRB CBNE
barryt at sbe.org
(323) 841-0682

Sent from my iPhone 5