Ballantine 9601M (AN/USM-413) Voltmeter Manuals?

[Red78]

I recently managed to get two surplus AN/USM-413 or 9601M voltmeters and probes at auction in seemingly working condition aside from the ancient 1974 and 86 nicads, but have absolutely no idea where to find a manual. I've found a basic spec sheet/ad on https://www.radiomuseum.org/r/ballantine_voltmeter_anusm_413.html, and some photocopied procedures for probe alignment on some old newsgroup website: https://www.bakersfieldads.net/Oildate-/Exports-/Ballantine-9601M-explosion-proof-ac-voltmeter-osha.JSP.

I imagine that there would have to be some kind of manual, whether stuck deep in some military publication archive that I can't find or in the possession of someone or some company who needed its explosion-proof water-proof drop-proof rugged awesomeness. For the life of me though, I can't seem to find much of anything except some rare mentions on forums and some probes on ebay. I suppose I could always go to Ballantine and see if they could sell me one if they had them still but I'd like to not go that route if I can. They seem to work as they should but I'd like to find a manual to have for reference should they need to be repaired in the future, after I clean the crud off of them.

[daisizhou]

Which website did you buy this multimeter from?

[Neomys Sapiens]

Huh. I have to look that up. I have one, and my inventory list says manual = Y, but I have no idea now whether this is a real manual or a paper version of the mentioned spec sheet.
Theoretically, there should be a TM or TB in the 9-6625 series (OPERATOR’S, ORGANIZATIONAL, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE).

[Red78]

Theoretically, there should be a TM or TB in the 9-6625 series (OPERATOR’S, ORGANIZATIONAL, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE).

Yeah that's where I started to look for it, I looked through the Library of Congress, liberatedmanuals, and the Hathi Trust library, I couldn't even find a mention of it in all the documents I looked up. I read through an index of TMs I found published in the early 80's and another in the late 90's, I didn't see it in the 9-6625 series or the 11-6625 series. There didn't even seem to be a mention of actually using it in any of the other available manuals to repair or modify equipment either. The only mention I found was oddly in a index of JETDS designators published this past June, but the index didn't provide any other information than what the AN/USM-413 was: a voltmeter.

I did however find an italian magazine on the Internet Archive that published an article about it (I assume it's a review) and other surplus equipment in 2004, it fortunately has some schematics photocopied on it, aside from that I cant really read italian that well. I also found tons of classifieds for it that advertised it with a manual, a listing in a catalog, and another magazine ad, but not much else. The article with the schematics is attached.

Which website did you buy this multimeter from?

I bought it at a local auction.

[Neomys Sapiens]

I found my documents pertaining to it. It is a 2-sided commercial spec sheet and two additional pages for the AN/USM-413 proper. And a TWELVE page manual for the probe.
Will produce clean scans within the next 2 weeks.

[Neomys Sapiens]

Here are the scans: