Classic Floppy no show :(

[andif]

Hi everyone im sorry if this is in the wrong place. A friend of mine asked me if i could get the floppy drive working on his Macintosh Classic. I had a look and found a lot of corrosion on various chip legs, very nice cobalt blue colours. After some cleaning and replacing the capacitors on the logicboard it still does not recognise a floppy drive. Should i replace one of the chips that could be a controller ?

I found an old non working unit which i used the Logic board and the floppy drive works but no sound on this one. So i have ordered some new capacitors for this one too in hope that if i replace them the sound will come alive. 

Ive googled for logicboard labelling to try and work out what chips could be at fault but didnt find any. 

Any help would be appreciated. 

 

[olePigeon]

The SWIM chip controls the floppy drive.  However, I've never replaced one.  Maybe someone on here will chime in with something more helpful.  At the very least, recapping and cleaning the motherboard is a good start.

 

[Elfen]

Cobalt Blue colors? Sound to me that the battery exploded in this unit at one time or another.

You need to trace out the pins of the SWIM Chip to the floppy port. Since this is a Classic and not a Classic II, the traces should be thicker and easier to see so follow the traces to the Internal floppy port and to the external floppy port. You may have to patch up a few dead traces with some soldering of thin wires from chip to connector. It's a tedious job...

Q: Does the hard drive work or is it dead too? Probably for the same reason and the same thing needs to be done to fix it.

The dead one probably needs some work on the Analog board, so if you can fix that you can have 2 Classics.

 

[andif]

Hi, thanks for the replies. The Hard drive works fine on the original board which i shall call "1" just the floppy drive doesn't work. The second board "2" Floppy drive worked but no sound. This morning i just replaced two capacitors located behind the reset switches, but now each floppy i tried can not be read and requires ejecting or initialising. So im guessing as I have tried 3 floppy drives and two ribbons that I might need to replace the other capacitors on "2". Would anyone happen to know where there is a diagram showing pin - track locations for "1" ?

Thanks again for your replies. 

 

[andif]

Ok quick update, just used the multimeter and did a continuity checks on both boards and they both produce the same matches from the pins to the legs on the SWIM chip. Bare in mind the one that is still failing to see the floppy drive has had the 7 SMC replaced and the second board hasnt and it can see the floppy drive how ever it is now saying that all disks are unreadable and require to be initialised. :-/ Suggestions?

 

[Macdrone]

Floppy drive needs repaired or replaced.

 

[andif]

Floppy drive needs repaired or replaced.

I have 3 of them and one was working but now reports disc not readable but all 3 floppy drives report same error. 

 

[olePigeon]

I assume you tried a different floppy disk?

 

[andif]

Yeah 4 all previously readable

 

[Elfen]

Are they readable on the "Good Mac" or is that where the error is coming from?

I'm hoping that this is not the case of a killer Mac. I've seen this with Apple IIs where the drive is installed incorrectly by one pin and a chip on the Disk Drive fries out; and any disk you put in it gets erased and any other drive you put on the card fries out the same chip. This would be the first time I ever heard of this happening on a Mac. If true, sounds like a bad IWM.

 

[bibilit]

another issue i had more than once, old floppy disks can be dirty, leaving deposits on the drive heads.

Once this has been done, the drive is unable to read anymore, even a previous "good" disk.

Cleaning the head solves the problem.