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+---- Thread: Writing HxC 300rpm images to disk on a JU-475-4 (/showthread.php?tid=843)
Writing HxC 300rpm images to disk on a JU-475-4 - rmzalbar - 07-29-2021
HxC seems to export converted images to 300 RPM .SCP files only, such as in the case of converting .D64 to .SCP. There's no choice to master a 360 RPM image.
Therefore, these can't be written by a JU-475-4 with Supercard Pro because the drive stays at 360 RPM even when low-density mode is selected in SCP software. This only produces unusable tracks.
Of course, maintaining a 360k 48tpi drive is a solution; but potentially alleviating the issue, I found this mod to add a simple hardware override switch to force the JU-475 motor to 300 RPM:
http://dunfield.classiccmp.org/img47321/speed300.htm
However, is there a jumper on these drives I'm not aware of that selects the speed or allows speed select when low density is selected? I'm checking if I'm missing something obvious before I try this this 300 RPM hardware speed modification.
Thank you - Rob
RE: Writing HxC 300rpm images to disk on a JU-475-4 - admin - 07-29-2021
Yes, there are jumpers for controlling the speed. I have never seen any HxC .d64 to .scp actually work, even on a 300 RPM drive. I need to go look at see what is wrong with that conversion.
RE: Writing HxC 300rpm images to disk on a JU-475-4 - rmzalbar - 07-30-2021
Actually, my HxC .d64 conversions started working when I began writing them back with an ancient 48tpi, single-head, full-height drive. I overrode the setting so I could use Index mode (since HxC aligns the tracks) and voila. I am assuming 300 RPM made the difference. I am using the current development snapshot of HxC which is 2.5.6.9. The drive is an "MPI model 51" from 1984.
I emailed an HxC converted scp file to data (NickFaldoChampionshipGolf.7z)
Do you know which jumper will control the speed on a JU-475-4?
Edit: I found the BX jumper which changes speed to 300 RPM.
And.. yes, I can't get a good write from the HxC image with JU-475-4 even at 300 RPM. It looks OK, but gets a read error around track 32 or so (bad sector) when booting above game on real 1541, and imaging a d64 from the disk again from SCP gives me an image that won't run in VICE - it crashes at the crack screen. However, I do get a working disk from the 48 tpi drive, although you must override to force index write.
RE: Writing HxC 300rpm images to disk on a JU-475-4 - admin - 07-30-2021
HxC always generates index align tracks (for all formats), so you need to use the INDEX mode when writing disks back.
Drive speed should not matter with SuperCard Pro. You should be able to write an image successfully on any speed drive. Drive speed variations are handled by the SuperCard Pro board. I will look into this.