FC9801 computer FDD replacement

clingel
Posts: 13
Joined: Wed Aug 15, 2012 2:21 am

Re: FC9801 computer FDD replacement

Post by clingel »

And in the case of the Hxc firmware you know exactly where the clock is so there is nothing missing you can just generate the clock in the loop that encodes the mfm or fm data stream.

Jeff
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Re: FC9801 computer FDD replacement

Post by Jeff »

clingel wrote:And in the case of the Hxc firmware you know exactly where the clock is so there is nothing missing you can just generate the clock in the loop that encodes the mfm or fm data stream.
No. There are only a stream for the HxC. It doesn't "understand" what it stream.
There are no loop encoding mfm or fm into the firmware, just a data streamer from the sdcard:

https://hxc2001.com/floppy_drive_emulat ... format.pdf

A new hardware is currently designed with an FPGA. This one integrate the VFO/Data separator.

But for the moment you need the external VFO with the actual hardware.

EDIT : Anyway thanks a lot for this document : the page 18 seems to show an Data separator schemactic without any specialized circuit. Very interesting.

clingel
Posts: 13
Joined: Wed Aug 15, 2012 2:21 am

Re: FC9801 computer FDD replacement

Post by clingel »

Jeff, Is the FPLA version of the floppy emulator with the data separator still in the works? My machinist friend has finally decided to go ahead with his conversion. I built a data separator from a single AtTiny that decodes an actual floppy stream so it will also work with the emulator, but if you have a version with the separator built in it saves me from building and installing one in his CNC machine.

-Charles

WishIhadaMits
Posts: 1
Joined: Fri Dec 07, 2018 3:53 pm

Re: FC9801 computer FDD replacement

Post by WishIhadaMits »

Hey there - I came to this thread after searching all over the net for info on how to get my old Japax wire EDM going. One drive has seemed to die completely, and the machine won't boot unless it can read both drives at the same time. I swapped the drives in the PC-9831 enclosure along with the jumpers, but no luck. My disk drives are FD1135D.

There is only one place in US that still services these machines, and if you own one then you already know who they are. We bought our current "refurb" floppy unit from them about a year ago for $1300 and it's already on the blink. That was after we tried two of their previous units with no luck. And of course, their warranty is only for 90 days. :evil: They'd be more than happy to sell us another complete unit, or one with newer drives for $1600, or their very latest innovation - the USB adapter model for a mere $2,000.

I do not want to give these people any more money, but my knowledge of old hardware and programming is dismal compared to the members here. If all I could do is find a way to swap a newer-style floppy disc drive into this enclosure I'd be happy, but a USB adapter would be fabulous.

I've read this entire thread several times and just feel rather overwhelmed. If anyone here has successfully completed a Japax EDM conversion I'd love some guidance. I'd be happy to chat over the phone as well if someone would be so inclined. This company is just bending us over at every turn and I'd love to fix this machine completely without their help. Thanks for reading.

Jeff
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Re: FC9801 computer FDD replacement

Post by Jeff »

The HxC Floppy Emulator was tested on these machines, but you probably need the additional board to generate the missing VFO signal. These boards was made several years ago and are now sold out. i will ask Lotharek if he still has some units.

skippysmt
Posts: 7
Joined: Thu Aug 02, 2018 11:11 pm

Re: FC9801 computer FDD replacement

Post by skippysmt »

I have done 2 machine now in the UK you need to buy a board from kitahei88 in Japan first of all and the SD reader. Around 80 to 90 pounds for this board
The hardest part was to copy the disk .Jeff just help me with the last one I did after I copied it using kryoflux as I had a speed issue when converting them back. I did not know about a file I had to attached to the back up call rpm300rpm360 to change the speeds once done it was very easy.
I can take a photo of the pin setting on my Elvy Japax. I have been using mine at home now for 4 years without fault.

tuanpqvn
Posts: 2
Joined: Sun Jun 21, 2020 2:07 pm

Re: FC9801 computer FDD replacement

Post by tuanpqvn »

clingel wrote:
Fri Aug 17, 2012 9:56 am
I ran the full analysis. When the scan reaches an unformatted track it runs through a bunch of bit rates and then puts an 'N' at that position on the screen, so there are 'N's at track positions 77h0, 77h1, 78h1, 79h0, and 79h1 when it is done.

Here is the file: http://infoconix.com/programs/clingelfloppies2.zip

-Charles
Link is broken. can you reupload the file?
thank you very much

adimat
Posts: 3
Joined: Thu Dec 14, 2023 11:42 am

Re: FC9801 computer FDD replacement

Post by adimat »

Hello dear participants,
Got a very old EDM LDM50 from Japax co with JAPT4G system/ with the known and analysed here problems.
If there is anybody here that solved the issue it will be for me a great help and a great opportunity to work together.
From the dates of your messages seems to pass a lot of years, very sad for me that I was not discovered this place before, very interesting forum.

techscan
Posts: 2
Joined: Fri Dec 15, 2023 1:31 am

Re: FC9801 computer FDD replacement

Post by techscan »

Hi,

I'm in the same boat. I've been working on this problem now for 3 weeks and haven't been able to find a solution. I have a Japax LDMS and my floppy drive is dead. I've tried talking to people that make the emulators but none of them will contact me about this particular drive. They say make an SD card of the system disk and then their emulators will work. They don't seem to understand that I CANNOT read the disk.

I found a pc9801vw2 in Japan that just I purchased yesterday for $178.00 but I don't know if it will work. Stab in the dark. I'm now talking to an emulator manufacturing company in Germany that says if I send them a disk and some other details they think they can help me. Talked with them again today and waiting to hear back.

I figured I'd reply to your post as we have the same problem and it won't hurt to share our research. If I find anything else out or a direction forward I will post to this link again. Please do likewise and maybe we can got this sorted.

Buzz Scheuhing
Techscan Industries

adimat
Posts: 3
Joined: Thu Dec 14, 2023 11:42 am

Re: FC9801 computer FDD replacement

Post by adimat »

Thank you Buzz,
My computer was partially affected by weather and mice, it's supply was out of order.
After some tries the computer starts for 5 seconds and stops again, having done all I could imagine.
I have found in Bulgaria a very nice and passionate lab that sent me a program that could read the system floppy but nothing works.
Also I found in China a company that could refurbish in their way, if something works I will post here.
Very, very disappointed about this situation, the machine looks great mechanically and the number of patents used are impressive.
Hoping the best,
wish you and our forum Merry Christmas.

adimat
Posts: 3
Joined: Thu Dec 14, 2023 11:42 am

Re: FC9801 computer FDD replacement

Post by adimat »

Hello again dear Forum,
My Japax LDM50 is now with a supply for the NEC pc that works . After hours of measuring, tests looks that changing every part sometimes solves the issue:)
The problem remains, no readings from the Floppies, the Led marking their function is just lit in a orange colour for an instant that floppy is inserted.
Once for two times, the PC plays a 3-beep that indicated a try to start and a lack of RAM or Bios, the other tries got no sounds . Changing the battery was not the solution. Believe that some contacts or corrosion could produce that reaction. The floppy units are a very robust construction, incredible that are not responding well.

I'm trying, trying, not getting off, hope the best :)

techscan
Posts: 2
Joined: Fri Dec 15, 2023 1:31 am

Re: FC9801 computer FDD replacement

Post by techscan »

Hello Adimat,

I have some useful information for you. First, if your drive blinks momentarily but does not continue to boot there are only a couple of explanations. One it that the disk you have is not being recognized as a system disk or two, the data separator on the drive is no longer working. Either way I have some good news to report.
Working with HxC and a company on the website FloppyEmulator.com, I have managed to not only find out all about these disks but have been able to scan them with their software to create an image for their emulators. I have also used a KyroFlux board to create a clone of the floppy. So there are two ways to go depending on what you want to do.
First, if you want to eliminate using the 30 year old floppy drives than you'll want to go with an emulator. The first thing you have to do is buy a still readily available Samsung SFD-321B floppy drive. The reason for this is that the Japax floppy drives run at 360 rpm versus the 300 rpm almost all other drives run at. It needs a couple of modifications to work at 360 rpm and high density mode. Pin 2 on the cable connector has to be connected to ground and a jumper soldered across the contact OPA. You need to put this drive in an older computer with an original floppy drive because it requires the floppy disk controller to work. USB floppies will not work. I used an old Gateway running Windows XP and it works great.
Once done, contact FloppyEmulator.com and download their software "FlexiScan" or HxC and download their software. With this software you can scan and image the disk and send them the files. They will create an SD card from the image and preinstall it in the emulator. The emulator also works as a dual floppy drive as well for the maintenance disk and storage floppies. The only other drawback is you will need a VOF data separator card between the emulator and computer. I bought one from Japan for around $76.00. The floppy drive was $49.00. The Flexidrive emulator is pricey at around $365.00 but you can get one from HxC a whole lot cheaper and they work just fine.
Now, if you want to clone the disk you will need to buy a Kyroflux board from Germany. It will extract raw data and do a 1-1 clone of the disk that bypasses their copy protection and will work in your machine. That cost me about $160.00 but it will also work with any floppy drive from an older computer even running at 300 rpm. Again, USB will not work.
Lastly, about the disk format. The disks are 83 cylinder 77/2, 500kbs, 26 sectors MFM /256 bytes per sector 1mb 2HD. However, here is the rub. The copy protection is that Track 0-0 is FM and 128 bytes per sector. All of the others are MFM /256 bytes per sector. If you don't have a computer that can read that mixed format on Track 0-0 and Track 0-1 you can not read the disk. One other note. Even though the disks are 77/2, the system disk (bootable) has a string written on Track 78-0 but track 78-1 is blank. This identifies it as a system disk and the computer will boot to it. When you check the Maintenance disk or the formatted storage disks they will have the same copy protection on Track 0-0 but Track 78-0 is blank.
Sorry for the length of this post but I'm recapping a couple of weeks of work here to get to the end of the tunnel. Hope this information helps.

Regards,
Buzz

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