On Sat, Jan 7, 2023 at 2:15 PM Francesco Messineo <francesco.messineo_at_gmail.com> wrote: > > On Sat, Jan 7, 2023 at 2:11 PM Rhialto <rhialto_at_falu.nl> wrote: > > > Just a silly idea. I think you can probably see this with your scope. Is > > the disk you're trying actually formatted in 8250 format and not 4040? > > The bit speeds would be different, but maybe (just maybe) an incorrect > > speed SYNC might just be recognized? > > nope, I'm sure my friend used his other 8250 (non-LP) since we worked > remotely to make that one work before. actually I *might* have a clue now: I measured the main crystal oscillator on the 8250LP and it's 11999486 Hz, which is a bit out of spec from the nominal 12000000 Hz (according to the datasheet it must not be lower than 11999990 Hz). This obviously makes the zone clocks a bit lower than they should be. I don't know however if this difference can justify the drive not reading other disks. I'll see if I have a spare 12 MHz oscillator in my parts.... FrankReceived on 2023-01-07 16:00:02
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