So I was able to salvage a GS from our local ewaste facility and I've been able to get it up and running with ADTPro (speediboot however doesn't work, and I seem to be only able to transfer over serial with pin 8 on the gs serial port empty). Trouble is it only had a 5.25" floppy drive, and I have no disks (and no money to buy them online). I do however have a couple Mac Pluses, a couple LCs, A Mac II, a Classic II, and an M0130 external drive (ewates has been good to me). So I'm flush with mac 3.5" floppy drives and I have a 20 pin ribbon to DB-19 adapter from the M0130.
From what I've read the original 3.5" floppy of the GS was the same model as the internal 800k floppy from the plus and that even later superdrives could be swapped in, though you couldn't use 1.44mb.
I've been reading the BMOW blog on the FloppyEMU. He goes into quite some detail on the signals on all 19 pins of the GS port and all 20 pins of the ribbon connector for the mac and Apple 3.5" drives. Now since I'm not trying to daisy chain anything, just connect the Mac Plus floppy to the GS, everything I read seems to indicate that I would just need to jumper pins 16 and 20 together to get it to work, however after doing that the drive doesn't spin on startup at all. The heads move slightly, but that's it. It isn't seen in ADTPro at all so I can't format anything
So what I'm wondering is what I have to do to connect a single 3.5" floppy drive to the GS. These drives are working, they have been tested in a Mac previously.
Do not connect that drive. Some of the Mac 800K drives can burn out the IWM chip.
Some may work, but the risk is too high. The Apple 3.5 Drive (with eject button) works on the //gs, //e (with 3.5 Drive Conntroller), or any Mac with a disk drive port. The Mac drives OTOH, may lack some circuitry to protect the IWM.
If you have already used it, check if you can still read the Floppy Emu on the //gs. If you can, then your IWM is safe. if not, then you ave already fried it.
I've purchased some very solid drives from Herb Johnson at a rather reasonable price. If you need a //gs drive, I suggest contacting him for them. Just specify that you need a SONY 51W drive in a case with an eject button. He restores them fully prior to posting them out, so unlike the eBay lottery, you will receive a properly working mechanism.
For the Floppy Emu, I advise buying the little Daisy Chainer adapter board. You will likely want at times to boot the //gs with the Floppy Emu, and at others, have it connected but boot from a 3.5 or 5.25 drive; and the //gs has a very specific order for how drives must be connected to its Smart Port, to recognise their type. For the Floppy Emu to properly work on the //gs in all of its available modes, with other drives, you need that dongle.
Well, I can't connect the Floppy EMU as I don't have one. Can't afford it. I can't afford to buy any replacement parts. I'm working with what I've got. But from everything that I read, the AppleDisk 3.5 that was released alongside the GS used the exact same floppy drive as the Mac Plus and the SE with the 800k drive. So to get it spinning do I need to do something with pin 4? Will it only spin if an Apple formatted disk is in the drive?
I get confused too. But the 3.1/2" drive will need to have an eject button. They are called unidisk drives "A2M2053" and work only with the Apple II+, IIE, etc etc. But that is kind of a tricky thing. Then you have this drive model Apple 3.5" Drive (A9M0106) that still has a eject button but can be used on both iigs and macintosh. So no eject button. no work from what I can tell
Thanks,
Josh
Most have the same drive mechanism (some have a slight difference reuiring a special cable, that had to do with the eject protocols), but they do not have the same IO card inside the case. You risk shorting out the IWM, which would ruin your //gs entirely, by using the Mac version of the 3.5 drives. Buy an Apple 3.5 Drive from 1986 or later, with the eject button, and sell the other drive, if you want; but no, using that drive on the //gs is not intended.
Some may be safe, but in my experience, this is a good way to blow the IWM, or the slotmaker, or both, which someone did to one of my //gs systems. It can no longer pass the //gs logo splash screen and locks up immediately thereafter because someone stupidly connected a Mac 3.5 drive to it. Some Mac drives wire their cables direct to the mechanism, whereas the //gs drives have an IO board in-between the mechanism and the system.
I'm not using a case. I'm not using an external drive at all. The M0130 drive is incompatible (400k single sided), I'm just using the 20pin to 19 d-sub cable. I am using the 800k drive from my mac plus.
Based on this pinout of the GS disk connection:
https://www.bigmessowires.com/2015/04/09/more-fun-with-apple-iigs-disks/
And this description of the signals on the 19pin cables:
https://www.bigmessowires.com/2015/03/17/apple-smartport-pin-directions/
And further what the daisy chain board actually does here:
https://www.bigmessowires.com/2015/03/25/apple-ii-emulation-forever/
The AppleDisk 3.5 ( A9M0106 ) is just a bog standard 800k Drive used in the Plus and the early SE (https://www.bigmessowires.com/2015/04/01/apple-ii-800k-3-5-disk-emulation/) connected to a daisy chain board which just figures out where the 3.5" drive is on the chain, but leaves the drive controlling to the computer itself.
So the only signal going in to the IWM from the drive is RD and WRPROT, RD is the same across all Apple IIs and Pin 10 is an input to the drive signal from the Mac so on a GS nothing would be sent on that line, both the drive and the IWM would be waiting for a signal.
So I think I have to build an adapter as seen here https://www.bigmessowires.com/wp-content/uploads/2015/04/db19-to-idc20-b.jpg to get the actual drive detected right. I'm not sure why connecting pin 20 and 16 together doesn't work like it does on the EMU when all the signals should be the same, but It isn't so I'm trying the next thing.
Unless someone has a daisy chain board (or just the chip from it) they're willing to send me.
Stop that, before you destroy the system. Connecting the drive mechanism direct to the //gs with a straight cable like this is almost certain to cause irreparable damage to your //gs mainboard. You may already have destroyed it.
That diagram is for the Floppy Emu, which has detection software to determine if it is connected to an Apple II, Mac, or Lisa, and a mode select to determine what signals its FPGA sends to each pin. It isn't intended for SONY drive mechs. Just because they all have a 16-pin header doesn't mean that they are electrically compatible.
a2-daisy-chain.jpg
This is what you are missing, to permit using the SONY 51W on the //gs.
The ribbon on the left, connects to the drive, and the //gs drive cable connects to the header on the right. I believe that the drive cable is wired differently to those use on the Mac Drives, as well. I don't have one of the external 800K Mac drives anymore, so I can't check the pinout easiy.
The Appe 3.5 drives are cheap as heck. Buy one, even if it doesn't work; then you can swap the 800K mechanism into its case via this board, and it will work on either system. Buy a working drive, and it will likewise, work on both.
Do you have a 5.25 drive to test if your smartport still works? If you've fried it, then there is nothing that you can do. I hope this isn't a ROM3 that you are casually shorting out. :(
P.S. The SmartPort is not hot-swap safe. Never connect or disconnect anything while it is under power.
Apple_3.5_Drive_Schematic.pdf