[Amps] TL-922 --> 21st century

[Vic K2VCO]

I have a stock TL-922 that I want to update. I'm going to do the following:

-- step start
-- vacuum relay QSK
-- automatic bias switching to cut off tubes when not keyed
-- check / adjust filament voltage
-- replace VHF choke in plate circuit with glitch resistor
-- improve bypassing of HV and filament power leads
-- no, I'm not doing anything to the parasitic suppressors except checking the resistors!

A question:

The grids are grounded via a parallel combination of 3 220 pf capacitors, a 4.7k resistor 
and a 470 uh choke. I don't understand this. I am tempted to just strap the grids to 
ground. What were they thinking?

-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/