Convert PDP-11 RK05 disk pack to PDP8

Apart from screws, an RK)5 pack seems to consist of : Upper Housing Lower Housing Hub Magnetic plate on bottom of hub to lock to the drive spindle Magnetic Disk Clamp plate to fix the disk to the hub A bloc kfo foam i nthe middle of the hub :-) AFAIk, and everythign I have check confirms this, the difference is the hub only. The PDP11 hub has 12 sector notches (13 nothces total), the PDP8 one ahs 16 sector notches (17 total). The ring wit the sector notches in it is integral with the rest of the hub. In theory you can swap the hubs over. But be warned the disk is only fixed by the claming plate, there is nothing to centre it. Yoy would ahve to do that by hand (I suspect you'll neeed a spare spindle, a diak gauge, and a lto of patience...) The other problem is that the only source of 16 sector bubs is the rare PDP8 version fo the pack. I suppose you might be able to clut the extra ntoches in the exiting hub and somehow block up the ones in the wrong palce, but.... Some people have rported usign what is effectively a digital PLL to plater the timign of the sector pulses and use 12 sector packs with a PDP8. I've not tried it... -tony