Re: Avometer Model 40 Special (7.5mA FSD)
The cutaways are due to me using my 'live testing chassis' Peter, which was homebrewed from a severely bowed Model D case! Going back in time a couple of years, it occurred to me i could make this jig rather than throwing out a 'D' case which was bowed in by 3/8" at the rear. It has come in very useful for testing and tweaking meters without damaging them- and also for posing photographs.
I do recall seeing an identical glass multiplier in a Mod 48A or 47A (Early 1940's as you say)
The V shunts are certainly accurately wound enough to challenge the accuracy and resolution of the DMM's which i am using to check them- it had not occurred to me that a Model 40 would normally have component resistors by 1947 (as i have no other contemporaries to compare it to, only a MkII of around 1970 vintage which is of course full of precision sky blue resistors)
I'll get some more images uploaded, i have just bypassed the o/c V trimmer shunts (shown on the wiring diagram as nominally 500 ohm each) with discrete 1/4w resistors and am achieving expected accuracy on DCV ranges. I am just about to check the rectifier against 240vAC and 13vAC.
Dave
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