MarsMan2020
Experienced Member
Does anyone have a PDF of the patterns that would be stuck onto a floppy spindle used with a strobe to measure the speed?
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Floppy Spindle Speed Patterns
- Thread starter MarsMan2020
- Start date
Chuck(G)
25k Member
The patterns differ between drives that spin at 300 and those that spin at 360 RPM. Which do you have--and what size?
Better to use program that simply times the space between index pulses, I think.
Better to use program that simply times the space between index pulses, I think.
MarsMan2020
Experienced Member
I don't have any easily accessible machines old enough to have a floppy controller that exposes the index pulse.
They are 1.2 MB 5.25 drives, with no readily available manual online. I am trying to determine if there is a way to get them to run at 300 RPM.
I guess it might not be too bad to jumper in a motor on signal and measure the index pulse timing with a logic analyzer.
SomeGuy
Veteran Member
What model are they? Someone else might have some information.
Exactly what are you trying to do here? Some 1.2mb drives do in fact have jumpers or options that let them run at 300RPM. However, this mode is not very useful. In this mode a 1.2mb drive can be used as a quad density (720k) drive on a low density controller. It can NOT operate as a proper compatible 360k drive because it is still a 96TPI (80 track) drive rather than 48tpi (40 track).
MarsMan2020
Experienced Member
What I'm trying to do? Find a copy of the patterns that you stick on a floppy hub to measure the spindle speed with a strobe light.
They are Hitachi drives made for IBM:
TYPE: HFD516CI2U
P/N: 61X4618
E/C: A26985
DATE: 89 09
Same drive on eBay - https://www.ebay.com/itm/IBM-5-25-H...sk-Drive-HFD516CI2U-P-N-61X4618-/322978785371
The only reference I have been able to find online is that they were used in some kind of 'communications controller' to load firmware updates. I picked up 2 for $10 each at VCF last fall, at the end of the last day when everyone was marking down stuff they didn't want to carry home. I have tested them in Linux on a circa-2009 motherboard and they work fine as 1.2MB drives. They are nice drives with the beefy cast housings.
I would like to use them in my Vector Graphic MZ in place of the original Micropolis drives. I understand that they won't read/write discs that were written on the Micropolis drives, but if I can get them set to 300 RPM I should be able to use them with some blank hard sector media without any modifications to the original controller or software being needed.
MarsMan2020
Experienced Member
In case anyone ever needs to know, J1 in the middle of the PCB switches the speeds between 360 RPM (default, no jumper) and 300 RPM (with jumper).
Chuck(G)
25k Member
I don't know about that. Some later drives aren't very tolerant of HS media. I've got one or two here that go "not ready" (unresponsive) when HS media is used.
It would seem to me that you're going the expensive way round. I'd just opt for a 96 tpi 5.25" DD drive. (say a Teac FD55F)--it's less likely to have issues with the hard sectoring Alternatively, you could use Deramp's hard sector simulator and run a 3.5" drive (really cheap) on your system.
It would seem to me that you're going the expensive way round. I'd just opt for a 96 tpi 5.25" DD drive. (say a Teac FD55F)--it's less likely to have issues with the hard sectoring Alternatively, you could use Deramp's hard sector simulator and run a 3.5" drive (really cheap) on your system.