800k Floppy drive question

CharlieFrown · May 7, 2019

Hi,

I have two 51W floppy drives, which have the same issue - do not respond at all, no spinning, no clicking, checked the eject motor gears and seems ok.

Cleaned the head. Nothing. Nada. No idea what I should do next. Maybe the stepper motor is dead?

BTW I used two different yellow striped cables.

lowlytech · May 7, 2019

The limit switches at the front of the drive, make sure they don't need a spray of deoxit maybe. I don't know for sure, but I figure one of the switches is to tell the system a disk has been inserted. Otherwise I know all the drives I have gotten needed disassembled and relubed. Just followed these instructions for the drive from my SE/30 and it is now working great.

https://wiki.68kmla.org/Floppy_drive_lubrication

bibilit · May 7, 2019

Yes, two switches, one for disk detection (right IIRC) , the other one for write protection.

The disk carrier is pushing the switch when falling down.

So pushing the switch down manually is a first step for troubleshooting your drive (should spin the motor)

CharlieFrown · May 12, 2019

do you think I could use 800k drive from the SE with my Plus?

Dog Cow · May 12, 2019

Yes.

You can also put an FDHD SuperDrive in the Plus and it will function as an 800K drive.

Crutch · May 12, 2019

Dog Cow said:
You can also put an FDHD SuperDrive in the Plus and it will function as an 800K drive.

@Dog Cow something tells me you will know the answer to this: if I replace the IWM chip on a Plus with the SWIM chip from an SE FDHD (which as I recall has the same package) and put a SuperDrive in the Plus, would it work? Or do I maybe need to upgrade the ROM too, if that’s even possible.

LaPorta · May 12, 2019

As far as I know, IWM and SWIM are not pin compatible.

Dog Cow · May 13, 2019

Crutch said:
@Dog Cow something tells me you will know the answer to this: if I replace the IWM chip on a Plus with the SWIM chip from an SE FDHD (which as I recall has the same package) and put a SuperDrive in the Plus, would it work? Or do I maybe need to upgrade the ROM too, if that’s even possible.

Yes. The upgrade from 800K to SuperDrive requires a new ROM too. ROMs were socketed on the logic board just for this eventuality.

As far as I know, the only two Macintosh models which had an official Apple FDHD upgrade path were the Macintosh SE and the Macintosh II.

See also: SE w/FDHD and lower price, August 1989

Crutch · May 15, 2019

Dog Cow said:
Yes. The upgrade from 800K to SuperDrive requires a new ROM too. ROMs were socketed on the logic board just for this eventuality.

As far as I know, the only two Macintosh models which had an official Apple FDHD upgrade path were the Macintosh SE and the Macintosh II.

See also: SE w/FDHD and lower price, August 1989

Thanks! So if I replace the IWM on my Plus with a SWIM, and steal the ROMs from an SE FDHD (or an SE/30?), and swap out the drive, the Plus could use a SuperDrive? I’m not sure why but I kind of l like the idea of a Plus that can read HD disks.

In theory I would think one could assemble an appropriate PTCH resource, stick it in the system file and not need a ROM upgrade. (I assume it was the Disk Driver that changed.). However I suppose nobody would ever have created such a PTCH, since getting a FDHD required a SWIM anyway so might as well just pop in some new ROMs while you’re in there ...

LaPorta · May 15, 2019

Still uncertain as to

if that will work on the plus itself though. I’m not sure the IWM is the exact same

physical chip a in the II and SE.

olePigeon · May 15, 2019

I wonder if someone could make an IWM to SWIM adapter for the Plus by looking at the pinout on the SE and II.

Dog Cow · May 15, 2019

Crutch said:
I’m not sure why but I kind of l like the idea of a Plus that can read HD disks.

There were 3rd-party high density floppy drives. Applied Engineering made HD drives for Apple IIgs and Macintosh. Look into the AEHD+ Drive.

AE Plus Drive Version 3.5 External Floppy "High Density for all Macs including Plus, SE and II"

From the 68000 Mac FAQ:

Code:

...QueComp (tel: 612-623-0903) should have out-of-business Applied Engineering
AEHD+ Drives for $99 (you may find one cheaper from flea markets or user
groups). Resurrect your old Plus or SE that does not have a SuperDrive without
having to replace the board in the computer (impossible on the Plus; expensive
on the SE). AE made three external floppy disk drives for Macintosh and Apple II
computers: 1. AEHD+ Drive - SuperDrive Compatibility for the Mac Plus, SE and
II. 2. AEHD 3.5" Drive - 1.44MB Drive for SuperDrive Equipped Macs. 3. AE 3.5"
800K Drive - 800K Drive for Macintosh and Apple II Computers.
The AE HD+ can read/write/format 1.4MB floppies on 800K floppy based compact
Macs. The Mac II requires an optional (not included) AE floppy interface to use
the AE HD+, since the Mac II case does not have a built-in external floppy
connector. A major drawback is that the AE HD+ cannot be the startup disk drive;
not as a 1.4MB floppy and not even as a 800K floppy. The other drawback is that
you've got to have the AEHD+ extension (takes 32K on disk) to use the drive even
as a 800K floppy drive (i.e. you must startup off another drive that contains
the AEHD+ extension). AEHD+ extension is compatible at least with System 6.0.7
and 7.5.5.

There also used to be Drive 2.4 from Kennect Technology that plugged into the
floppy port of a MacPlus and allowed it to use 1.4MB disks. It could also format
them to a proprietary 2.4MB size.

Crutch · May 15, 2019

Thanks! I know about the AEHD+ and have had an eBay alert on that for a while now. I’ve yet to see one for sale anywhere. (Anyway I’d much prefer an internal SuperDrive aesthetically, but still, would love to have an AEHD+.)

CharlieFrown · May 22, 2019

Despite lubricating and cleaning the drives, they show no signs of life. Checked those switches too. Any ideas?

If my IWM chip is bad will I be able to boot from external drive?

Dog Cow · May 23, 2019

CharlieFrown said:
Despite lubricating and cleaning the drives, they show no signs of life. Checked those switches too. Any ideas?

Have those two drives ever worked for you?

If my IWM chip is bad will I be able to boot from external drive?

Unlikely.

LaPorta · May 23, 2019

This is a lot easier if you have another computer to test the drives with that you know works. Do you?

800k Floppy drive question

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