Thanks for sorting out the Rainbow driver smile
Sorry, i dont have deep links on Bitsavers for you.

(see circuit at bottom of screenshot)
https://dl.dropboxusercontent.com/u/37819653/BANNISTER/HLD%20-%20HLT%20-%20MOTOR%20ON.jpg

Source: Field Maintenance Print Set / MP-01722-01 from 1984 where the schematics of the RX50 controller can be found (scroll to end of document).

https://archive.org/details/bitsavers_decrainbowwSchematicJul84_3508632

Page 231 of the OCR version of Rainbow Technical Manual (pc100tm1_text) explains how the Head Load Circuit works -

- Disk present in the selected drive and the door is closed (DISK P H)
- drive is selected and the spindle motor is turned on (MPWR SEL H)

From the RX-50 Dual _Diskette Drive_ Specs:

Head settling time: 30 ms (maximum value)
Head load time: 30 ms (maximum value)

Source : QV069-GZ 100+ 100B Technical Documentation Apr85

That's about it all i could find.

Last edited by Bavarese; 06/06/16 09:33 AM.