Fred,
I do have a system disc. I copied it using my HP35665A, so I also have one for you. It's a single-side image copied onto a double-sided disc, so you might have to put some tape over the SS/DS sense hole before it'll work in your machine. (Older drives of course didn't have the sense pin, and so don't notice.)
I can send that to you, or I can send you the files via email, and you can use LIFUTIL to make your own. (I think you need a machine with a real floppy drive, not a USB one.)
Cheers,
Phil Hobbs