I tried replacing the ROMS on my Mac 128k motherboard, because I couldn't get a system disk to boot - tried two different disk, one 'new'. They didn't seem to work, of course....put the old ones back in, and now the internal disk drive is spinning at full speed before I even put the floppy in, and catches the receptor on the disk, but makes a bit of an unnatural screeching sound when it does. Not sure what I did. It wasn't doing this before. The Mac screen is flashing a disk icon with an X on it....anyone?
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Sony OA-D34V Disk Drive spinning like crazy!
- Thread starter Pashley
- Start date
Thank you for your reply. It just seemed odd to occur after I messed around with the motherboard....you have any advice, other than eBay, on where to get another drive?
bigmessowires
Well-known member
Does the Mac show a floppy disk with an X through it, even when no disk is inserted? If so, it thinks a disk has been inserted, which is why the drive is spinning. There's a mechanical switch near the front of the disk slot, it has a small plastic nub that gets pushed down when a disk is inserted. If that switch is sticky or broken, the computer will mistakenly think a disk is present when it's not. Try pushing the switch up and down a few dozen times. While you're at it, do the same for the switch that detects the write-protect opening in the disk jacket.
An 800K floppy drive can be substituted for 400K and will work fine, but I think the 800K is a different size, smaller than 400K. So it might require an adapter to install it permanently inside the Mac, I can't remember.
An 800K floppy drive can be substituted for 400K and will work fine, but I think the 800K is a different size, smaller than 400K. So it might require an adapter to install it permanently inside the Mac, I can't remember.
volvo242gt
Well-known member
Drive is slimmer, but, IIRC, the bracket is the same between 128, 512, and Plus...
Thank you, that makes sense! I did look into the front of the drive, and found two mechanisms that actuate when a disk is put in….one on the left, one on the right - and they seem to trip something when that happens….both seem to work ok…which side is the one you are referring to?
bigmessowires
Well-known member
It should be the one on the right - the one that's not aligned with the write-protect tab on the disk jacket.
If your drive is spinning but you don't see an "X" on the floppy disk icon, then your problem is likely somewhere else.
If your drive is spinning but you don't see an "X" on the floppy disk icon, then your problem is likely somewhere else.
Still an X on the floppy disk. I have tested the movement on the indicated mechanism...there is a red "eye" that is active when the drive is on, and the arm seems to drop down to obscure it when I insert a disk...still, nothing.....
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bigmessowires
Well-known member
I'm still not completely clear - you're seeing an "X" floppy disk on the Mac even when no disk is inserted in the floppy drive?
I also see a 0.22uF capacitor that's been bodged onto the pins of an IC near the front of the drive. Was that a previous repair?
I also see a 0.22uF capacitor that's been bodged onto the pins of an IC near the front of the drive. Was that a previous repair?
cheesestraws
Well-known member
Then yes, the drive thinks there's a disk in it. It may not be the mechanical mechanism but the actual switch that's gone - might be worth poking it with a multimeter.
bigmessowires
Well-known member
Yes, try disassembling it far enough that you can test the switch contacts with a multimeter while you press and release the switch button. The button might be sticky or dirty, preventing it from popping up all the way when there's no disk. Or there might be junk inside the switch that's conducting current between the contacts regardless of whether the switch button is pressed.
