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How do I identifxy a 5.25 HD/DD disk drive?

jens.hafner

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Joined
May 29, 2020
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I just received the 5.25" half height floppy disk drive shown in the pictures below. I want to use this in my 5170. The only designation I can find on this drive is a Model# NPH-502. The PCB says 8513-00 and NPH504/2. Is there any way to find out if this is a DD (40 Tracks) or a HD (80 Tracks) or some completely different drive? Is it save to just install it in my 5170 and try if it works as a HD or a DD drive?

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Not a lot of information available on this drive. It was made by a company in Taiwan called Tecmate, and model NPH-502 is a standard IBM compatible 360K DSDD drive.
 
If you can't find any information, what I would do is apply power and check for any odd voltages on the card-edge connector, just to be 100% sure there is nothing seriously weird with it that could cause damage.

Then attach it to an FDC and use ImageDisk to manually control it. Use alignment mode to manually step to the 40th tack. If it only seeks half way, then it is an 80 track drive. Check the RPM value, and if it spins at 360RPM then it is probably a 1.2mb drive. If it is 300RPM and has only 40 tracks, then it is probably a 360k drive. 300RPM and 80 tracks, then probably a quad density drive.

From there, try reading disks and formatting disks.

Keep in mind that if this drive was not designed for use in an IBM PC, there can be a number of differences. For example, it could flip between 300 and 360RPM depending on density. If HD, density select line could be reversed. It might support high density only operation. It might not have the same "ready" signal. (In other words, if it does not work it might not be broken.)
 
The Mitsubishi chip on the electronics board would seem not to support 1.2M, but I could be mistaken. This could also be a 720K drive, but IMD and a formatted diskette will sort that out.
 
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Not necessary to guess... as I pointed out previously, there is a single line listing of this make/model of this drive in an old catalog of Taiwan computer parts manufacturers which clearly lists it as a 360K DSDD drive.
 
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