OT: Master Instruments Multimeter specification and schematic

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Many here will know the name Master Instruments Pty. Ltd. Back in the era of
analogue measuring instruments they made very good meter movements and even
produced a general purpose field multimeter for use by the PMG Dept and the
defence forces. As supplied to the PMG it was designated APO Multimeter No. 3
and when supplied to the military it was designated Multimeter No. 4. I recall
that in the 1950's to mid 60's there were earlier iterations dubbed APO No.1 and

I have an APO No.3 which was originally supplied to an engineer mate of mine
back in 1971 at a total cost of $68.50 without the carrying case. A leather
carrying case was added later.

Since I wanted to have some manufacturers literature on this meter I prevailed
upon Master Instruments to supply me with whatever documentation they may have
retained, but I was not expecting anything.  I was rather pleasantly surprised
when they were able to supply a copy of the specification and a schematic.
Master Instruments no longer manufacture analog meters (or any other kind), and
95% of their business these days consists of supplying batteries.

Unfortunately, the quality of the documentation was not good enough for printing
with any degree of clarity so I have retyped the original specification in Word
format and added a hand drawn schematic of the meter.

If anyone would like a copy of this documentation feel free to email me for a

Re: OT: Master Instruments Multimeter specification and schematic
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**Great service. I found the same thing with Iwatsu. I required a
schematic to track a fault in a 100MHz Iwatsu CRO a few years back. An
email to Japan elicited an instant response with a full manual in .pdf

Trevor Wilson www.rageaudio.com.au

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