Mac LCIII upgrade with 475 board installation...floppy drive question

[Juror22]

I've gotten a 475 board and would like to just drop it into my LCIII case as an upgrade (of course that leaves me with two spare LCIII boards, but that's a problem for later).
If I do that, will it work with the LCIII's floppy drive? I don't think I can change the superdrive out for the manual inject drive I have, because the front of the LCIII doesn't have that inset the 475/Q605 does, so I am hoping that the superdrive will work - does anyone know? Has anyone tried this already?.

 

[opualuan]

I’ve done it. Auto-inject drive works fine. The LC gen 1 lid also fits the LCIII base if you’re building a real sleeper.

 

[Juror22]

I’ve done it. Auto-inject drive works fine.

Thanks, I know I could have just tried it out, but I'd hoped some brave soul had already tested the waters.

The LC gen 1 lid also fits the LCIII base if you’re building a real sleeper.

Now that is cool - next thing I'll look into once I dig my full 040 chip out of storage!

 

[Franklinstein]

There was a bridge period from about 1992 to 1994 where auto- and manual-inject drives were switching in and logic board upgrades were common, so several boards were available that could do both types (for example, LC 475, LC 575, Quadra 650, the NuBus PowerMacs). Some models such as the Quadra 630 never had an auto-inject drive option so none of those drawer-type logic boards support them without modification (which is why a lot of Power Color Classic mods either don't have a functioning floppy drive or have had a cable mod done to support them).

 

[nathall]

I didn’t think the logic board could tell a difference? I’ve used manual inject drives as replacements for dead auto inject drives in Mac II line computers that existed long before manual inject was a thing. My IIfx has one auto and one manual at the moment and both work fine.

 

[Franklinstein]

Honestly I've never run a manual drive in a II. I never saw a reason to. I prefer the autos in either case. They're less PC.

It's possible the manual inject drives are tolerant of undesirable signals in a way that the older autos aren't. I know they switched a couple pins around for the manual drives and so running an auto on those later systems (basically any PCI Power Mac) would cause it to make all kinds of racket until you modified the cable (basically just cut pin 9) or unplugged the drive.
That's not the first time Apple did that, though: back in the day if you used a cable of the wrong variety (yellow vs. red stripe) and/or tried to upgrade an early Mac from a 400k drive to an 800k drive without also using the correct cable, you'd have a problem where the drive would run the eject motor constantly.

 

[Juror22]

The LC gen 1 lid also fits the LCIII base if you’re building a real sleeper.

You folks are a real bad influence on me! I thought this was way too good an idea not to try out, so now I own an original LC that I have just successfully, recapped, but since it missed my flurry of retrobriting this summer, I may have to try out one of the indoor alternatives.

 

[volvo242gt]

Honestly I've never run a manual drive in a II. I never saw a reason to. I prefer the autos in either case. They're less PC.

It's possible the manual inject drives are tolerant of undesirable signals in a way that the older autos aren't. I know they switched a couple pins around for the manual drives and so running an auto on those later systems (basically any PCI Power Mac) would cause it to make all kinds of racket until you modified the cable (basically just cut pin 9) or unplugged the drive.
That's not the first time Apple did that, though: back in the day if you used a cable of the wrong variety (yellow vs. red stripe) and/or tried to upgrade an early Mac from a 400k drive to an 800k drive without also using the correct cable, you'd have a problem where the drive would run the eject motor constantly.

This. Basically, an auto-inject drive on a PCI or newer PowerMac board will run the eject mechanism continually. Only way to prevent that is to modify the cable, or just unplug the eject motor mechansim, turning it into an auto-inject, manual eject drive. So, I wonder if using a yellow stripe cable with an MP-F75W drive will make it work correctly in a 7500 or similar machine.

 

[nathall]

Yeah, I remember the yellow vs red stripe thing from working on the older Macs years ago.

I guess I’ve never tried an auto inject in a later model, only manual injects in the older ones. If I have a drive go down, I usually swap it out with whatever I have around that’s working until I can repair it.