I am looking for records related to NASA's Saturn V telemetry system. Specifically, I want to find out if the telemetry used an SNX1304 to optically isolate the PCM/DDAS system and the internal circuitry of the computer interface unit (CIU).

We found your question to be so interesting! Here are some responses from archivists across the National Archives, which I hope are helpful:

The Saturn V was in use during the Apollo era, so the records they want will probably date to the 1960s-1970s?  I checked the catalog, and there is an organizational authority record entry for "National Aeronautics and Space Administration. George C. Marshall Space Flight Center. Saturn Projects Office. ca. 1961-ca.1972." 

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There was also a Saturn V Program Office at George C. Marshall Space Flight Center, though the related records seem to focus on rocketry rather than telemetry.

https://catalog.archives.gov/search?q=*:*&f.level=series&f.creatorIds=10501986

Maybe also the Astrionics Lab
https://catalog.archives.gov/id/10503154

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Another source they should consider is the NASA History Office.

History Home

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Since most of our Saturn V records have ITAR sections, he would have to do so without taking any notes or scans--provided he is an American citizen.

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That could be in Research and Development Project Files in the Saturn V Program Office, and I got a hit in our Qualification and Test Plan Reports index for a report on "Electromagnetic Interference Evaluation of S-IVB Telemetry Ground Support" from September 1966.

It may be best to direct him to atlanta.archives@nara.gov, though. At the very least, we can send him our Saturn V report indexes and he may have a better idea in what kind of report that answer might show up in.