[R-390] 390A Line Level meter replacement..?

[Jordan Arndt]

Hi group....

The 1960 S-W 390A I'm working on has no Line Level meter and I'm looking at 
re-working a couple of the correct size and style of meters that I have on 
hand to install as such.

Has anyone determined whether the original meter had copper oxide rectifiers 
inside the meter..?

Was it a single diode, a full-wave or a bridge rectifier...?  I've gone 
through the archives and haven't found a definitive answer to that question.

One of the 390As I have has a substitute Line Level meter and a diode bridge 
external to the meter which works well enough for my purposes so I'd be 
happy to copy that circuit until I can find an original Line Level meter.

I've already installed a replacement Carrier meter with an LM741 op-amp ckt. 
driving a substitute meter which works very well.

Any info will be greatly appreciated...

73...Jordan VE6ZT