Is my FDS compatible with FDSStick?

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oRBIT2002
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Is my FDS compatible with FDSStick?

Post by oRBIT2002 »

I've been following this guide here to check if my FDS is compatible with FDSStick.
https://www.famicomworld.com/forum/inde ... pic=2934.0

My chip says FD7201P which seems good. But the circuitboard doesn't entirely match any of the ones in the guide above. Someone knows better?
I'm interested in getting an FDSStick and proper cable to be able to write disks from my PC...

I attach a photo of the circuitboard.
20220605-165629336.JPG
Pokun
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Re: Is my FDS compatible with FDSStick?

Post by Pokun »

You may have a FD7201P drive chip, but they comes with different power boards and the later revisions of it also has a simpler write protection circuit you need to defeat if you want to be able to write disks. FDSStick, FDSloadr or whatever doesn't matter they all need a write-capable drive to write disks.

Here is a guide how to handle various revisions of the power board.

Remember that rewriting a disk makes it only work on the disk system that wrote it, so don't write over good disks.
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oRBIT2002
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Re: Is my FDS compatible with FDSStick?

Post by oRBIT2002 »

Pokun wrote: Sun Jun 05, 2022 12:40 pm Remember that rewriting a disk makes it only work on the disk system that wrote it, so don't write over good disks.
Oh I didn't know that. So if I write a disk from my PC (using FDSStick etc.) it can only be used on my device?
NewRisingSun
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Re: Is my FDS compatible with FDSStick?

Post by NewRisingSun »

Pokun wrote:Remember that rewriting a disk makes it only work on the disk system that wrote it, so don't write over good disks.
That is news to me.
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Re: Is my FDS compatible with FDSStick?

Post by Pokun »

Yes at least that's what people have reported (I only have one drive myself so I can't check). Basically if another drive should be able to read the disk it must be tweaked similarly to the one that wrote the disk, but even if you succeed in doing so it may not work with official disks anymore.
I'm not sure why this is the case, but I guess the disk drives used in the FDS are cheaper than those used in the Disk Writer kiosks as the FDS drives are only meant to read disks and write to single existing files, so it was enough if they could read what the Disk Writers and factories produced.
When dumping prototype disks people were required to do careful tweaking until these disks could be read.

Some people have claimed in the past that it is possible to tweak an FDS drive to the point that it writes disks correctly like the Disk Writer, but the trustworthiness of those sources are doubtful, and no one has shown any kind of proof or shared the techniques required to do so.


So rewriting disks are basically only useful if you have a disk that is bad anyway or has been rewritten by someone else, and the disk should probably be marked as rewritten for the future. Please don't flood the FDS market with useless disks.
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oRBIT2002
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Re: Is my FDS compatible with FDSStick?

Post by oRBIT2002 »

Is there a difference between "writing" and "writing?
I mean. ..If a game save the highscore to the disc (=writing), would this cause issues if a friend borrows the disc to play on his FDS?
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rainwarrior
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Re: Is my FDS compatible with FDSStick?

Post by rainwarrior »

I think the issue is mainly about the alignment of the head. If you're a little off centre, you can still read something that's dead centre, but a different drive that's off centre the other way might be too far from your alignment to be able to read properly.

Part of what makes the quickdisk "cheap" is it just has one spiral track instead of concentric circles like other forms of floppy disk. Instead of a stepper motor that moves in very stable increments of distance, it has a screw that continually pulls the head along while the motor spins.

This is much more prone to errors of alignment. Instead of being able to reference against a stopper for track 0, it has to start the spiral at both the right distance and the right point in the rotation.

I dunno how they were aligned in the factory. There's an adjustment on the spindle which is kind of inconvenient to reach. People seem to just try adjustments of that until it loads a reference disk (video example), but there's not really a good way to know how precise you've got it, just whether it loads or not.
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Re: Is my FDS compatible with FDSStick?

Post by NewRisingSun »

I would expect competent adjustment to yield properly-aligned head, spindle and drive assembly positions. There are several markings on the spindle and on the white wheels to accomplish that. The linked video's author does not seem to take these markings into consideration.

There must have been sufficient reliability with disks written using a standard disk system across different units. Game Doctor disks were always copied in store basements using standard disk system hardware:
vlcsnap-2022-06-06-20h03m39s373.jpg
... and since they fill up a disk's capacity completely, Game Doctor disks are much more demanding in terms of proper alignment.

In fact, I would even be a bit surprised if the Disk Writer kiosk were found to not use the standard Mitsumi Quickdisk drive seen in regular disk system units.
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rainwarrior
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Re: Is my FDS compatible with FDSStick?

Post by rainwarrior »

Yeah there had to be a good factory process for competent calibration. I don't know what it is, though.

It might be possible to write FDS software that operates the hardware directly and can give a read on that? I've seen alignment software for regular floppy drives like this.

Alternatively maybe there's some test points on the board that can be hooked up to an oscilloscope or something that can compare against a reference?
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Re: Is my FDS compatible with FDSStick?

Post by Pokun »

I see, I guess that all or nearly all FDS drives had their stock belt melted by now and has all been repaired, resulting in a large number of misaligned drives circulating. That may explain why a disk written on one drive never seems to work on another nowadays.

80sFREAK (member on this forum) often claimed that he knew how Nintendo's factories did it, because he had some insight in mass-production. They didn't use a caliper, according to him, there was a simpler method, but he never said what the method was.

The information most people follows can be summarized on EricJ's FDS homepage.
It's the caliper method and there are no mentions of any markings. It shows how to tweak the magnetic head, the spindle hub and drive speed. Somone said that teaking the spindle hub is asking for trouble and should only be done if it has already been messed with by a previous owner. There should be some pink glue on the screw if it's untouched from factory. But it may eventually need to be tweaked over time.

There used to also be a pretty detailed guide with pictures over at Famicom World forums, but the pictures were uploaded to a picture upload service that decided that forever was too long a time to store pictures and wiped them all at some point.

Then there's the Copymaster disk that can measure the drive speed that people use for tweaking that. Loopy also made some tool for FDSStick that could do that. It's here somewhere on the forum.


If there is a reliable method to adjust the FDS to correct factory setting so that all (non-broken) retail and Disk Writer disks works, I think that method should be documented somewhere, like on the wiki.
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Ben Boldt
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Re: Is my FDS compatible with FDSStick?

Post by Ben Boldt »

A normal FDS drive may only be able to write a thin or weak stripe on the disk, whereas the factory may have written a much thicker or stronger stripe that is more forgiving to different alignments. It is also possible that rewriting a disk does not fully erase the previous data when writing. The result may improve if you thoroughly degauss the disk before writing to it.
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Re: Is my FDS compatible with FDSStick?

Post by Pokun »

How would you do that safely and efficiently?

oRBIT2002 wrote: Mon Jun 06, 2022 9:53 am Is there a difference between "writing" and "writing?
I mean. ..If a game save the highscore to the disc (=writing), would this cause issues if a friend borrows the disc to play on his FDS?
As far as the the write protection circuit found on most FDS boards goes there is a difference between writing to a single file and formatting/writing the whole disk. I don't understand the details but it can somehow tell them apart and disallows the latter while the former is allowed, otherwise you wouldn't be able to save progress in games.

I've never heard of problems reading or writing save data on a disk between different drives, and I've never had such problems myself. If a disk works in my drive I have always been able to save to it (far from all games saves though). As long as you don't break off the write protect tabs.
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oRBIT2002
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Re: Is my FDS compatible with FDSStick?

Post by oRBIT2002 »

As far as the the write protection circuit found on most FDS boards goes there is a difference between writing to a single file and formatting/writing the whole disk. I don't understand the details but it can somehow tell them apart and disallows the latter while the former is allowed, otherwise you wouldn't be able to save progress in games.

I've never heard of problems reading or writing save data on a disk between different drives, and I've never had such problems myself. If a disk works in my drive I have always been able to save to it (far from all games saves though). As long as you don't break off the write protect tabs.
Makes somekind of sense.. So in theory perhaps you could copy a disk file by file instead of some kind of raw-diskcopy?

Anyway, this entire mess makes me slightly sad that these things are so complicated. The FDS would need some more love from the community/hardware-gurus to help preserve this cool device/disks for the future.
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Re: Is my FDS compatible with FDSStick?

Post by NewRisingSun »

So in theory perhaps you could copy a disk file by file instead of some kind of raw-diskcopy?
If you are talking about copy protection, then only block type #1 is checked.
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Ben Boldt
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Re: Is my FDS compatible with FDSStick?

Post by Ben Boldt »

Pokun wrote: Tue Jun 07, 2022 11:29 am How would you do that safely and efficiently?
I don't know, I have not done it myself. Is there a danger in degaussing too strongly? I remember machines that could wipe out VHS tapes this way. Did that hurt the tapes? I don't know. I am not seeing how it would hurt it unless it heated it up and melted. Maybe that "wears it out" somehow? I get what you are saying but I just don't have a clue.
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