Hitachi FDD-412A 8 inch floppy drive

[Jeff]

Can you share the stream files ?

[CNC_USER]

I played with Kryoflux and disk drive connections and finally managed to get some results. First track appears to be FM, all others MFM. A bit of headaches made FDD-412A signal pinout names. MFM GATE shoud be connected to DENSITY LINE pin (pin 2 on 34 pin Kryoflux floppy connector).

[brightcaster]

The MFM gate on the hitachi FD-4122A actually does a little bit more than changing filters alone (like density line does). It looks as if it switches the inbuilt data and clock separator from FM to MFM decoding also! Without setting MFM gate you get very obscure data while decoding MFM. It still looks more like FM (2 bands), but with a lot of bits at wrong positions!

David

PS: Details are at https://forum.kryoflux.com/viewtopic.ph ... 6&start=10

[CNC_USER]

PS: Details are at https://forum.kryoflux.com/viewtopic.ph ... 6&start=10

This is my topic there. Im now stopped at writing new files back to disks.It seems that it is possible to decode/find a way how to change NC specification bits to add new functions with the help of HEX editor.

Can you share the stream files ?

They are in brightcaster's shared link.

[brightcaster]

To get things right you have to take track 0.0 from this set (drive set to FM mode):

https://failiem.lv/u/mncvs7ejy

And all the other tracks from this set (drive set to MFM mode):

https://failiem.lv/f/szfgdna3g

Or am I wrong because the two images are from two different floppies?

David

[kurmay]

Hi

Can you re share raw image files from both okuma floppies.
I have an utility for read/write osp formatted floppy.
I can seperate and create all files in floppy images.
Thanks

[ausfan]

Unfortunately, I don't have any manuals for the FDD-412A drive or the controller, and I was not able to find anything on the Internet. So any more detailed description would be welcome!
Here is our current jumper assignment in the Okuma Campus 5000 systems:
Hitachi_FDD-412A_Jumper.jpg

Thank you for your help!

Apologies for piggy-backing onto this post, but I have one of these drives that I'd also like to get working.
Does anyone have the pinouts for the power connector? I've not had any luck finding a manual or any pinout details.
I'm hoping an FDADAP board will sort the data side of things.

Thanks.

[someoneontheinternet]

For anyone having this drive, I just want to mention that I found the service manual over at The Internet Archive.

To configure the FDD-412A without VFO operation, jumper it for "Mode 4" (it's by default Mode 1). If your goal is only to read the raw un-decoded bitstream, however, that should in all cases be exposed on pin 45 of the connector if the drive is selected. I decided to just use this instead of changing any jumpers.

In short, JP1/10 selects the VFO source, between JP1/9 (bitstream from disk) or JP1/12 (bitstream from pin 45, ie. from any currently selected drive that is on the same cable). This way you can have one VFO-drive do the decoding work for a whole set of drives.

To help with this, you have JP1/16 that selects enable mode of the VFO output pins (pin 33/35/39). Jumpering to J1/15 will disable those outputs entirely, to J1/14 will enable them only when the particular drive is selected, while no jumper enables the VFO output pins of the drive continously (regardless of the drive being active or not).

The last noteworthy jumper is J1/11. This selects what ends up on the data output pin (pin 33). To J1/13 selects decoded data from the VFO, while to J1/9 selects the un-decoded bitstream from the disk (which will always, as mentioned, be available on pin 45 when the drive is selected and active). The main purpose of this is to make a model-A drive behave like the non-VFO model B.

[ausfan]

Want to jump again in discussion- did You guys have any results with the drive? Im trying to get data from installation disks (OKUMA OSP5000M-G), but I cannot figure out- where exactly is DATA READ pin/output. From the pictures here an output shoud be on pin 37 (Data area). But I managed to get something out from disks(that looks like flux stream, but Kryoflux doesnt understand it and thinks that it's unknown data) only on pins 35 (Separated data) and 39 (Separated clock).But if we take a look on circuit fragment which is also here, they are inputs!!! And that circuit is not from this floppy drive- its from device side, not the floppy drive. And how to understand that note in pinout about pin 37: Used as FILE DATA-N by selecting short plug? Please help- this drive is driving me crazy.
Guntis

Hi, not sure if this is still relevant or if you ever got a reply, but on the Hitachi drive it's labelled a 'File-Data' and on pin 45.
I spent a long weekend translating Shugart pinouts to their Hitachi equivalents and can now read and write from a PC to the FDD-412A.
Dave.