Ivc ~ ivc-871p ~ 1" video recorder service manual

[ppppenguin]

This normally reliable reference says the Great Time Machine was alpha: http://www.labguysworld.com/Quasar_VR-1000.htm

Philips 1500 (first domestic cassette VTR) and 1700 were also coaxial spools in a cassette. The wrap was ordinary 180 degree omega.