Has anyone ever monitored the B+ line voltage in the R-390A with a DVM and an o'scope?  If you have, what is the B+ voltage and peak to peak ripple voltages at the terminals of C606A and C606B?  An octal test socket will come in handy!

The cost reduction report does not mention what the B+ ripple is with the L-C-L-C filter.  They were obviously more concerned with reducing the R-390A heat load.  The original R-390 report mentions the maximum voltage variation of about a volt in the regulated power supply and a ripple of 0.1 volts over the line voltage limits.  I didn't find any mention of the R-390A's B+ voltage value or it's ripple amplitude in the cost reduction report.  One would think that this question would have been addressed long ago in the Pearls of Wisdom.  If it has, I didn't find it.