Mac SE Floppy Drive Compatibility

[techstep]

Hi All,

I recently purchased a Mac SE Dual Floppy model on eBay because the case was in very good condition. The seller said it didn't power on, but this was vague so i bought it anyway to see if I could figure out what might be wrong. Well, it suffered the all-too-common red battery explosion and the chassis and logic board have major damage. 

Onto the question: this particular SE is the first I've seen with Dual 1.4mb floppy drives and no hard drive. Even the box states they are apple Apple original drives, shipped from the factory. I have a spare SE logic board from a dual 800K floppy machine. Would this board work with 1.4mb floppy drives or is there an incompatibility with firmware? Mostly curious as i don't want to damage either the drives or the working logic board.

 

[LaPorta]

That will work fine in a pinch. 1.4 MB drives Will function as 800ks with the older ROMs, there is no issue. Actually, if the board is toast but the ROM chips and SWIM are ok, you can transplant them to your spare board in place of its ROMs and IWM chip. That was an Apple-approved upgrade back when.

Im unaware of ANY original dual 1.4 MB drive version in any form. What leads you to believe it was equipped that way? In fact, how do you know they are 1.4 MB drives? Got some pictures?

 

[techstep]

That will work fine in a pinch. 1.4 MB drives Will function as 800ks with the older ROMs, there is no issue. Actually, if the board is toast but the ROM chips and SWIM are ok, you can transplant them to your spare board in place of its ROMs and IWM chip. That was an Apple-approved upgrade back when.

Im unaware of ANY original dual 1.4 MB drive version in any form. What leads you to believe it was equipped that way? In fact, how do you know they are 1.4 MB drives? Got some pictures?

Here's a couple of pictures. I have the original box so that's why I believe it came that way from the factory. Never knew this was an option, any other dual floppy SE I've seen has been 800K.

Anyhow, got around to swapping parts around today. Replaced the logic board,  metal frame (old one was quite rusted from battery explosion), and power supply (also rusted). Happy to report the SE now boots up to the blinking question mark!

The original logic board with the ROMs support 1.4mb floppy drives is badly damaged, but as you suggest I'll see if I can salvage the ROM chips and SWIM. the Rom HIGH chip has some corrosion and I know the person I bough the SE from tried to turn this on, so i hope they didn't get fried. Will clean off and swap in to see if they still work, sometime soon.

 

[LaPorta]

Well wouldn’t you know it? It says on the box! I need to check my sources.

 

[Franklinstein]

It's amazing how much documentation on obscure systems gets lost over the years. But yes, there was a dual SuperDrive SE available for a while. It likely went specifically to the education market like the double floppy LC.

But yeah, you can use a SuperDrive in an 800k Mac and vice-versa, but only 800k disks will work in either case (the former because the IWM doesn't know what to do with 1.44MB MFM disks, the latter because an 800k GCR drive only reads 800k GCR disks regardless of the SWIM or ROM combo). Unless of course you swap the ROMs and the SWIM, as mentioned, in which case you'd have full SuperDrive compatibility. This was a legit upgrade for both the SE and the original Mac II.