[Milsurplus] FW: Solid-State BC-221

[Hubert Miller]

I had my water distiller appliance up on the table and taken apart for repair, and I wanted to have the hand - drawn schematic I'd drawn long ago, just to check if my schematic was accurate. To my surprise, I quickly found the schematic, which is untypical.
But, in looking thru the paper file, I also found a couple articles:

"Solid - State BC-221 Frequency Meter";   QST magazine;  Feb. 1977 p 35, 36
"With very little effort these instruments may be modernized with FETs, with no sacrifice of accuracy, by changing and adding a few components. In the author's model no recalibration was required, and the instrument now operates from a small 9 volt battery."  

"More on Solid - State Conversion of BC-221 / LM Frequency Meters";  QST Dec. 1979, p 59.

These articles should be read together. 
Result is DC draw of  2 - 3 mA at 9 volts; RF output 1/4 original level; audio volume 1/2 of original. These values could possibly be increased if you wish to do the work ( higher battery voltage comes to mind. )  Due to variability of FETs you will have to select a couple resistors for optimum.
Maybe these articles are available online. If not, I will "eventually" scan them, but cannot do this right now.
-Hue Miller