Macintosh Classic Issue - floppy disks not working in OS 7.X (Working in 6.0.7)

[JohnnyPhantom]

Hey Everyone.

I recently got a Macintosh Classic (I'll post photos soon) that I took apart, and restored (cleaned up, new caps, repaired drive (for now, soon will be a Blue SCSI once the parts arrive from Mouser) cleaned and re-lubed floppy drive, etc. Has the 4MB of RAM upgrade, original mouse, keyboard, power cable, and a Targus carrying bag. I love it so much!

Here's the issue, the floppy drive works, I've created several new system install disks using my Windows XP PC and OmniFlop. If I boot and install OS 6.0.7, i can wipe the drive, install the OS, boot to desktop, pop in another floppy, open the disk and play the game (or whatever the floppy is).

If I load anything OS 7 it seems (tried 7.0, 7.1, 7.5.0, and 7.5.3) I can install the OS, but now any floppy disks no longer work when booted to the desktop. I pop them in, nothing mounts, nothing happens. if I force the floppy out with a paperclip, I'll get a "unrecognized disk" error message.

The issue was the same with the original SCSI drive as well as when I replaced the drive with a BlueSCSI

I tried with both a wipe of the drive and a fresh install of System 7.X as well as upgrading from 6.0.7 to 7.X, seems to behave the same

Is there an extension I need to enable? or something I'm missing? Not sure if it matters, but the machine has no PRAM battery installed. Also, not sure if there's a better way to do this, but when I install OS 7.X, I first boot the 6.0.7 system disk to erase the SCSI drive, then reboot, and then load the 7.X install disk 1 and install on a freshly wiped SCSI drive. Is there a better way to wipe the disk and install 7.X?

(Growing up I started with a G4 PowerMac with OS 8.6 and went up from there, became a Apple Authorized Tech, and serviced hundreds of Macintosh machines, but never had a or used 68K or OS 6/7 machine until a few weeks ago, So it's possible I'm missing something)

Thanks everyone in advance for all your help on this!

 

[Volvo242GT]

Got a copy of ResEdit? Might be good to check and see if the System 7.x System file has the .Sony driver resource installed. Seems like it isn't being added to the System file when that's being built by the installer.

Otherwise, it sounds like an issue with the logic board...

 

[JohnnyPhantom]

Got a copy of ResEdit? Might be good to check and see if the System 7.x System file has the .Sony driver resource installed. Seems like it isn't being added to the System file when that's being built by the installer.

Otherwise, it sounds like an issue with the logic board...

I tried using the Drive image of 7.5.5 from this site on the BlueSCSI (incase it was a driver issue, I'm not too confident in the 7 installer disk images I found online) so figured I'd try a pre-built image. Assuming it's fully there with drivers, I booted it on my Classic and same issue. If it's the logic board what would be the most likely chip? I have a spare logic board from another Classic I can swap chips from (the other board was very damaged from the battery, the current board in the machine had no battery damage, but leaky/bad caps before I swapped them all).

In System 6.0.7 the floppy works great and as it should. On 7 I discovered if I put the disk into the drive while the system is booting and once it passes the smiley mac icon, the floppy disk will mount and read. If I eject the disk, it ejects, but stays on the desktop.

I have another floppy drive I can try next, and memory expansion board (just incase it's any of those) looks like I got some part swapping to do.

 

[Volvo242GT]

That is odd.

Could be the SWIM chip.

You've tried the steps listed about 1/3 of the way down on this page, right? https://archive.org/stream/mac_Sad_...and_other_Disasters_4th_Edition_2000_djvu.txt

Look for the page 167 reference...

It does sound like you might have a bad floppy drive, but that doesn't explain why it works great under System 6. I'd be tempted to just set up System 6.0.7 or 6.0.8 on a partition on the BlueSCSI, or on the actual hard drive, then use the Desktop Manager extension to prevent System 6 from using its older style Desktop file and to use the Desktop DB and DF files that System 7 uses. When you need to deal with floppies, boot under System 6. Otherwise, you can use 7.x.

If you do find yourself using 7 a lot, I'd recommend a machine that's not limited to 4MB of RAM, though. If you still want a compact Mac, then a Classic II, SE/30, or Color Classic would work. The SE/30 is the only one of the three that can use more than 10MB of RAM without a logic board swap. If you're ok with a modular Mac, then any of the Mac II series machines, an LC series Mac, or an '040 Mac will do.

 

[JohnnyPhantom]

That is odd.

Could be the SWIM chip.

You've tried the steps listed about 1/3 of the way down on this page, right? https://archive.org/stream/mac_Sad_...and_other_Disasters_4th_Edition_2000_djvu.txt

Look for the page 167 reference...

It does sound like you might have a bad floppy drive, but that doesn't explain why it works great under System 6. I'd be tempted to just set up System 6.0.7 or 6.0.8 on a partition on the BlueSCSI, or on the actual hard drive, then use the Desktop Manager extension to prevent System 6 from using its older style Desktop file and to use the Desktop DB and DF files that System 7 uses. When you need to deal with floppies, boot under System 6. Otherwise, you can use 7.x.

If you do find yourself using 7 a lot, I'd recommend a machine that's not limited to 4MB of RAM, though. If you still want a compact Mac, then a Classic II, SE/30, or Color Classic would work. The SE/30 is the only one of the three that can use more than 10MB of RAM without a logic board swap. If you're ok with a modular Mac, then any of the Mac II series machines, an LC series Mac, or an '040 Mac will do.

Thanks for the reply. Is there a place that sells replacement SWIM chips?

I could take one of the board I was going to attempt to repair, but if I can just order the chip I'll do that instead of making the spare, possibly repairable, logic board a donor board . I'll swap the SWIM and see if that solves the floppy issue.

Most of the games I run will be fine with just staying in System 6. theres a couple that require 7, but due to only 4MB of RAM, I'll stick with a lower 7.0 or 7.1. Trying the 7.5.3/7.5.5 and that machine just struggles.

 

[fred1212]

Look at the buy and sell on here for another logic board

 

[JohnnyPhantom]

before I make the swap from the two classic motherboards, just want to make sure these two chips are interchangeable. Most of the numbers match. So I’m assuming that’s good. But the first two sets of numbers do not.
Thanks everyone!

 

[JohnnyPhantom]

I made the swap and it’s much worse now. Nothing happens on boot. Fan doesn’t spin and I get a rapid high pitched beeping. I’m gonna put the original swim back and hope for the best. If I botched it, is there anyone here who repairs logic boards?

 

[Volvo242GT]

That sounds like you've an electrical short. A high pitched flupping sound occurs when something is shorting out to ground. Is the floppy drive properly mounted in place, or do you have it hanging out the side, possibly touching the chassis?

 

[JohnnyPhantom]

That sounds like you've an electrical short. A high pitched flupping sound occurs when something is shorting out to ground. Is the floppy drive properly mounted in place, or do you have it hanging out the side, possibly touching the chassis?

That’s with no drives connected. Just the logic board and the power connector

 

[JohnnyPhantom]

The issue is (as far as I can guess) on the logic board, on the SWIM Chip connector, there's 3 sides of the chip where pin 5 and 6 (I think thats where it is, I'm going from memory as I write this) are joined from what my multimeter tells me. I can't see a sort visually on the chip or board, but the multimeter says there is. My best guess so far, is when I removed the chip, I used a hot air rework station, I then used solder paste and the air station to put the replacement on. With the first (there were about 3 or 4 attempts on installing this chip) before powering it on, I noticed that damn near all the pins were sorted together when I removed the chip, there was a HUGE blob of solder underneath, looks like the solder paste blew underneath the chip con was covering just about half of the area below the chip. I removed it all, cleaned up the board and chip, and tried again (wasn't as straight as I wanted, so did it a 3rd time) then noticed pins 5 and 6 on the sided connected, removed the chip again and tested the chips, no sort, tested the board, found the sorts on those pins. put the chip back on. (only the 1st attempt was with the hot air station and solder paste, the rest were with a iron and flux and solder spool). My guess is that when there was a big blob of solder from the paste, that maybe it caused a sort/connection inside the board between some layers? That's my guess so far. Still testing, cleaning, and diagnosing. I may just buy a new PCB and populate it

 

[Paolo B]

I recently swapped a SWIM on my SE/30 board. Donor was a busted LC. Used hot air for pulling from the donor as I didn’t want to damage the chip, but I clipped the damaged one, as I didn’t want to lift any pad on the destination board. I then carefully soldered it using a lot of flux and a fine tip. Took some time, but it did work.

 

[JohnnyPhantom]

I recently swapped a SWIM on my SE/30 board. Donor was a busted LC. Used hot air for pulling from the donor as I didn’t want to damage the chip, but I clipped the damaged one, as I didn’t want to lift any pad on the destination board. I then carefully soldered it using a lot of flux and a fine tip. Took some time, but it did work.

That's how I'll do it if I can't fix what I got and start with a new PCB. I'm not with the board at the moment, but I think I recall a large solder bubble on the bottom side of the board, may be from where all the solder seeped down from under the SWIM chip. When I get home I'm going to try to suck it all out from there and see how that goes

 

[JohnnyPhantom]

Ok, now I'm scratching my head. I got another complete Macintosh Classic, and this one is beautiful! it's already been refurbished, recapped, and cleaned. So I booted it up, and it had OS 7.1 preloaded. Popped in my floppy, and same exact issue as the other one (makes me thing I swapped the SWIM chip and damaged my board for nothing, but I'm not concerned with that right now, I'll fix it someday with a reloaded board) I tried my bluescsi with a clean 7.1 and 7.5.5 install, same issue. So now I've tried different logic boards, RAM expansion boards, ram chips, floppy drives, cables, CRTs (why not?) and even recreated the floppy disks on the mac itself incase its a omniflop issue. I've swapped everything. So unless this replacement machine with a working swim chip in OS 6 has is also OS 7 defective, I'm stumped. What's left? is there a firmware update I should do? I tried several different floppy images, and several floppy brands. Has anyone else seen this issue? I'll search on eBay for some original Mac Classic compatible game floppy and see if that works any better, but I dunno...

 

[fred1212]

Sounds very strange and the common link only seems to be the floppies themselves. You say you have tried different floppy brands so you have another computer that reads and writes floppies? and they work on that?. I have had issues with floppies working on one drive and not another for no apparent reason. I gave up on them and purchased a floppy emu much better than mucking about with the disks. A floppy emu would eliminate any problems with the floppy i/o and then you are left with a drive or disk problem!

 

[JohnnyPhantom]

Sounds very strange and the common link only seems to be the floppies themselves. You say you have tried different floppy brands so you have another computer that reads and writes floppies? and they work on that?. I have had issues with floppies working on one drive and not another for no apparent reason. I gave up on them and purchased a floppy emu much better than mucking about with the disks. A floppy emu would eliminate any problems with the floppy i/o and then you are left with a drive or disk problem!

I found a stack of floppies I found, a mix of written and factory disks, 800k and 1.44mb, same issues it seems. The ones I was trying were NOS pc formatted floppies that worked on my pc to formate and write them, and on the macintosh classic OS 6 to read them. Just the Jump to OS 7 seems to stop it. I like the idea of a floppy emu, I may get one. I just like the idea of using the old fashioned floppies that would be time period correct on the mac. I am also going to build an external DB25 bluescsi for transferring data over. I'll keep plugging away at this machine and see if I can figure out some rhyme or reason. I also put a disk in the Mac Classic with OS 6, formatted it, and wrote an image of a disk I transferred over with the internal bluescsi to the floppy, works in 6, not in 7.

 

[fred1212]

You are using System 7.6? What are they formatting too on system 6? 880k 0r 1.44k

 

[JohnnyPhantom]

You are using System 7.6? What are they formatting too on system 6? 880k 0r 1.44k

Formatted in os 6.1 and 7.5.5. Shows up as 1.44mb

 

[JohnnyPhantom]

I ttthhhiiinnnkk I'm getting closer. I'm at the point now in 7.5.5 where I can insert a floppy (even the ones that didn't work before in OS 7.x I created) and they will mount and read now, but when I eject them, the disk icon stays on the desktop and just kinda grays out. going to try wiping the hard drive/bluescsi and install a fresh install of the OS and see how it works then.

 

[JohnnyPhantom]

I ttthhhiiinnnkk I'm getting closer. I'm at the point now in 7.5.5 where I can insert a floppy (even the ones that didn't work before in OS 7.x I created) and they will mount and read now, but when I eject them, the disk icon stays on the desktop and just kinda grays out. going to try wiping the hard drive/bluescsi and install a fresh install of the OS and see how it works then.

Ok ignore that. It’s working as it should it seems. Finally the journey is almost over ^_^ the gray floppy icon is just from me clicking special and then eject disk. Instead I should be dragging to the trash. So far so good!