[Amps] Drake L-4B Should I or Shouldn't I?

[Don Jones]

Last year I picked up a L-4B from an estate sale. About a month ago I 
tried to fire it up. Looks like I got some problems to repair first. I 
did hear a thump come from the transformer of the L-4PS as it charged 
the high voltage cap bank. No biggie, also I did see the 3-500's light 
up in the RF deck.

What I did not see was any indication of High Voltage being present on 
the L-4B's voltage meter. Fingers crossed I do not have a blown meter. 
What should I see for pin to pin resistance of the High Voltage meter? 
Also what resistance should I see for the plate current meter? This has 
me puzzled, I would think that the meter should have shown that high 
voltage was present. I presume that this is a proper assumption. Correct?

Since I suspected there was problem, I stopped there and did not attempt 
to "key" the amplifier and see if it would tune up. I pulled the 240VAC 
power plug and let it set for a few days. After which I opened the high 
voltage power supply section and inspected it internally. The power 
supply has the original paper caps that came with it from the factory. I 
did not see any blown diodes or smoked resistors, the paper caps still 
had their guts which is a good sign.

After some thought and having good service from Harbach Electronics with 
a Clipperton-L power supply rebuild kit I decided to order one for my 
L-4PS so I could get those old caps and diodes replaced. I also ordered 
a new rebuild kit for the front panel power switches and a soft start 
kit for the amplifier too.

As for the Should I or shouldn't I question...
I am going to operate this amplifier with an out board QSK switch and 
bias control. I am thinking about hard grounding the grids and 
installing a 50k ohm resistor in the B- lead to cut off the tube instead 
of relying on the +150Vdc (or so) cathode voltage as designed from the 
factory.  I have heard "internet stories" claiming that the L-4B can 
become unstable if the grids are hard grounded. Something about the gain 
of the tubes becoming higher and unstable. Is this true or not? I do 
want to use this amplifier on all bands including 10 meters.

My bottom line goal is to run this amplifier at about 750 to 800 W rms 
out and enjoy it for many years to come. Looking for some technically 
sound advice and objective criticism. Sorry for being long winded. Thanks!

73, Don KO7i