800k floppy eject motor off the chain!

[mloret]

Hello! I am having a hard time with a 800k floppy drive I have in my Mac Plus. The good news is that it reads disks flawlessly. When I purchased the computer, the disk drive would make a loud grinding noise when I powered the machine on. When I disconnected the motor the noise went away. Upon further inspection, one of the wheels in the eject motor needed help. Okay, replaced that. Same noise. Swapped it out with another eject motor I have and same thing. So that leads me to conclude that the issue is with the drive itself, not the eject motor. Any ideas what this could be? Everything looks fine. I haven't done a complete disassembly yet. Any suggestions or tips would be appreciated.

 

[bibilit]

Sounds like the drive is trying to eject permanently (more like a broken gear again) i will hang the floppy outside the casing to troubleshoot the drive if i were yourself. Already seen a floppy drive board bad also.

 

[mg.man]

Okay, replaced that. Same noise.

When you did that, did you make sure the external "pin" was aligned properly? That pin trips a microswitch, which shuts the motor off. If not properly aligned, it could be your issue. I don't have to hand exactly how it's supposed to be aligned, but I believe with the drive mechanism in "ejected" state, the "pin" should be toward the front (farthest away from the rear) of the floppy. To align the pin, you need to remove that gear that was disintegrated, rotate the mechanism, then put that gear back in... HtHs..

 

[mloret]

Thank you for the tip! Yes, I have screwed that up before. I made sure that the pin was in the right place. Turns out it was the ribbon cable. Apparently I needed the cable with a yellow stripe, not the one with the red stripe. Still investigating why that is. Any idea what the difference is?

 

[bibilit]

IIRC (but can be wrong as i lost track of this information) the cable with a yellow stripe is for the 400k drive

 

[cheesestraws]

Turns out it was the ribbon cable. Apparently I needed the cable with a yellow stripe, not the one with the red stripe

One of them—I can't remember which—has a pin "missing". It's something like: the 400k drive uses an extra control signal that the 800k one does not, and for some reason if that signal is wired up then the 800k drive constantly ejects. An odd bit of design. I can't remember which way around the colours are.

I should have thought of that before, I've been bitten by it myself...

 

[mg.man]

I should have thought of that before, I've been bitten by it myself...

^ ...what he said!! ME too!!! Glad you got it working!

 

[mloret]

How do you cut a pin in the ribbon cable? Sounds scary!

 

[mg.man]

They probably just removed the pin from the IDC connector(s)... They pull right out when it's apart.

 

[mloret]

Ohhh...so pull the connector off and then pull the pin out huh. Wow, I'll have to try that and see. How do I know which pin to pull? I'm new to all of this in case that wasn't obvious :/