[MRCA] R-390A S-meter circuit query?

[DSP3]

I recently had occasion to remove and replace the signal strength meter 
in my EAC R-390A.  I tried the usual 500ua or 1ma meter but both gave 
low readings, as expected.  I also obtained a voltage amplifier board 
designed to make these substitute metes work.  These little amp boards 
do work.  That said, I see an Ebay offering of another substitute 100ua 
movement for the R-390A.  The seller indicates that resistor R-548 (AGC 
time constant cathode resistor) be changed from 27 ohms to 87 ohms.  My 
question is, is this a viable method, in general, to compensate the use 
of higher resistance meters (27 ohms vs 100 ohms and up)?  What might 
the expected results of the AGC circuit be, do you suppose, and would 
these changes be noteworthy?

Jeep - K3HVG

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