Use a 5.25" HD floppy to emulate a Tandon TM100-4?

[snuci]

I have a NABU 1600 8086 based computer that should utilize a Tandon TM100-4 drive. It runs CP/M 86 and QNX and I have disk images from Dave Dunfield's site. This computer doesn't have the mass storage unit (including the floppy drive) so is it easy to emulate a Tandon TM100-4 drive (96TPI) on a 1.2Mb 5.25" floppy? I have a Panasonic JU-475-3AG and have jumpered/removed jumper on the BX jumper as I believe it changes the RPM from 360 to 300 (I need 300 for the TM100-4 I think). Is it doable? Are there any other jumpers I should be concerned with?

Thanks,
Santo

 

[Chuck(G)]

Depends...does the NABU need a READY/ signal on pin 34? Is pin 2 NC? Otherwise, you should be fine. Alternatively, you could fit a 3.5" DD drive to the same cable.

 

[snuci]

Forgive the crudeness as I was trying to line up pins. Here is a rough drawing I made. Left side is the 34 pin card edge connector on the floppy drive, right side is the DB37 connector on the Nabu 1600 computer. It does need READY/ on Pin 34 and 2 is not connected on the DB37. I made a cable as everything looks like it lines up and it appears to work but I am having issues with the computer at the moment so it doesn't help me figure out if the floppies are okay or not. I need to fix the issue first before moving onto the floppies but while I wait for parts, I figured I would confirm this.

For the cable, I did line up pin 1 with pin 1.

You make a good suggestion with the 3.5" drive. I suppose I could make a 3.5" floppy with the same image. Thanks for suggesting that.
Santo

 

[Chuck(G)]

As far as I can tell, it should work fine. The big issue is 300 vs. 360 RPM.

 

[Eudimorphodon]

The RPM mismatch makes a 3.5” drive a better choice for this. The 1.2mb floppy drive was really meant as a replacement for 8” drives. (There are 360 RPM variants of 3.5” drives too, but they’re mostly confined to Japan.)

 

[snuci]

Just wanted to circle back and say that I was able to get a 3.5" floppy drive to work but I had to go through a few of them before I found one that would work. A normal PC floppy drive would not work. I had to go with a Chinon FZ-357 and the jumpers has to be set like the picture below. Note there are multiple versions of the FZZ-357 and I had two but only this one would work. Perhaps the settings are NABU specific but that worked for me.

I also tried to get a Gotek to work but I don't think it has the full signals that can be manipulated to work in this same way.



Thank you for the assistance, as always.

Santo

 

[Eudimorphodon]

I also tried to get a Gotek to work but I don't think it has the full signals that can be manipulated to work in this same way.

Did you re-flash the Gotek with FlashFloppy or another alternative firmware? The stock firmware is no good, but Flashfloppy works fine with TRS-80s.

 

[snuci]

Yes, I used the latest FlashFloppy on one (flashed it a couple days ago). I also have a genuine HxC Gotek and no dice there either. That said, I did use the HxC emulation on the FlashFloppy Gotek and did not use straight up Flashfloppy. If you have a pointer to the TRS-80 config settings and set up, I would be very interested.