tkc8800

Technology and retro computer blog

Macintosh SE/30 restoration

A few days ago I picked up an SE/30 from an ebay auction.  The seller was located near me so that was a bonus.  It was in fairly good physical condition but the case was very dirty and had paint stains on it.  The seller showed the machine at the disk prompt so that was a good sign as many of these machines are in a much worse functional state.  On getting the machine home, I tried to boot it using the Floppy Emu disk emulator but unfortunately I couldn't get it to work reliably.  I tried booting from several OS versions 6.05, 6.08 and  a couple of times I did manage to get it to boot to the desktop.  But it was pretty clear that the machine had issues. 

 

Over the last couple of days I disassembled it and cleaned it inside and out.  The case has come up reasonably good.  I managed to get all the paint stains and other marks off.  I cleaned the floppy drive mechanism and the drive is now able to insert and eject disks properly.  On re-assembly the boot problems still persist.  None of the logic board capacitors have visibly leaked, there is oxidation on some of the contacts of each capacitor and also on some of the ic's but the board is generally clean and in good condition.  So I was hoping to avoid re-capping right away.


These are the things I've tried on it so far:


- Boot using Floppy Emu and physical floppy, Floppy Emu will boot to the desktop on occasion, but machine crashes shortly after.  Physical boot floppy is not recognised
- It came with 5meg or ram, I've swapped the ram with other ram and tried different configurations, doesn't seem to change anything.  All ram is reported through the finder when I've been able to boot to the desktop.
- I've tried re-seating all removable chips,  no change
- Just prior to making this post, I removed all socketed chips on the logic board and then thoroughly washed the board with bi-card/white vinegar and then detergent.  It's in the process of drying out at the moment.  I'll re-try it once everything dries.





 

The SE/30 lives

I've been reading a few posts online which lead me to tinker with the Quantum 40s drive.  I figured as the platter motor was stuck maybe the head was too.  I removed the cover from the drive again and removed the magnet from the head mechanism and then adjusted the head tension screw.  Before re-assembling the hd I plugged it in with the cover off.  The head now moves freely, I hadn't seen it move before.  Not expecting much I plugged the drive back into the SE/30 and on second power cycle the machine started to boot!  It now boots reliably.  The drive is rather slow and sounds fairly sick, but the good news is that with a healthy and faster drive this machine should work fine.  I haven't replaced the caps yet and I'm still not getting a bong on start up, so this has given me some good motivation to spend some time re-capping the board.  I still can't get a response from the Floppy Emu.  With it booting now to the desktop, I tried loading a disk image from the Floppy Emu and there was no response at all.  The more I read into it I think the bourns filter might be the issue with reading floppy disks.  Some good progress.

 

 

11th October 2015

 I've managed to repair the floppy drive from the SE/30!

 I've been doing some reading on issues with these Sony super drives and determined that the issue with this one was that the top head was not making contact with the disk.  I put the drive in my LC475 with the cover off and lightly pressed down on the top head with my finger and it started to read properly.  I even did the same to format a disk and that worked too.  This is a common problem with these drives, because they sit around for years with no disk inserted, the head spring stays in the up position for a very long time.  The other cause is that people lift the top head to clean it and this can bend the spring up.  The spring on the top head is a bit of sheet metal screwed to the top of the head assembly so bending down is not an easy job because you can only bend down until the top head touches the bottom head, and this is not enough travel to bend it back into position.

 

To repair it I had to remove the head, this involves removing the two small screws holding down the slide bar on the head and also removing the two small card cables attached to the head.  Removing the head is fairly simple.  There is a second spring inside the head assembly which draws the two heads together.  This spring has three adjustment steps so you can increase the downward pressure on the top head.  So I  set the spring to the highest step.  Thinking this may fix it I put the head back into the drive and tested again.  Unfortunately even though the spring setting had lowered the top head so it was now touching the disk, the pressure was not enough.  Pressing down on the head with my finger was still required to make the head work.

 

So my solution was a novel one, I cut another notch on the bottom of the head assembly to make a fourth spring position for the internal spring.  I used a small hacksaw blade and cut a tiny notch further away from the last spring position.  Putting the spring in this fourth notch increased the pressure on the top head just that little bit more.  On testing the drive again unfortunately it was still not enough pressure to get the head working properly.  So I removed the head again and this time came up with another idea to bend the top spring into place.  I stuck a small flat screw driver underneath the sheet metal top spring so that the two heads were spread apart, then I pushed down on the top head.  This caused the sheet metal spring to be bent downward slightly.  Once again I put the head back into the drive and tested again and success, it now reads and writes without any assistance! 

See my detailed post about the head spring repair below.

 

13th October 2015

A further update on the SE/30.

I installed the Quantum 250 meg hard drive that came out of the LC575 into the SE/30.  I also re-installed the newly repaired Sony SuperDrive back in.  I then installed system 7.1 using some newly acquired (ebay), LC475 install disks.  The new hard drive had some old files on it so the first install worked but I got some extension errors on boot, some old files were messing with the new install.  I then tried using the system 7.1 disk tools floppy to wipe the drive but for some reason the 7.1 disk tools disk wasn't happy being booted in the SE/30.  It complained that it didn't work with the system version?  So I used the disk tools disk from system 6.0.8 and I was able to re-format the drive using that.  I then did a clean install from the 7.1 disks and it worked perfectly.  I now have a clean install of 7.1 running off of the new hard drive.  New drive is much more quiet and quick than the original, SE/30 boots in only a few seconds with 7.1 and seems to run really quick.

 

All in all the SE/30 is working well now.  It boots reliably and screen looks great.  I still haven't done the re-cap, I'm a little hesitant to do it when the machine is working so well.  The problems that still persist are:

 

  • No sound.  Most likely related to caps from what I've read.
  • Can't seem to use the external floppy connector.  I tried connecting a floppy drive to it and it wouldn't even power up.  The floppy emu works somewhat but continuously comes up with read errors.  Not sure if this might be related to caps or possibly a power supply issue

 

I guess the last reasonably simple fix to address the remaining problems  is to re-cap.  Would be great to have the sound working.


24th October 2015

I replaced all the surface mount capacitors on the logic board yesterday and I'm glad to say it went well.  I wasn't getting any sound before, now I get clear and loud sound through the headphone jack.  But unfortunately I'm not getting sound through the internal speaker.  I plugged in another internal speaker (smaller), and I get faint sound through that.  So I checked the voltages at the plug that connects to the logic board (with the plug removed),  I'm getting -11.1v and +11.62v on pins 7 and 8 on the connector.  The 5v supplies are fine.  So I suspect that there's some issue on the analog board or power supply.
 

The SE/30 generally runs great, screen is good, SCSI port works fine, internal drives work fine.  The only things I have issues with are the internal sound and the external drive connector.  Whenever I connect a drive or Floppy Emu to the external connector it's very flaky.  Not sure why the internal drives are not affected.  To fix the 12v supply I'll look at doing a re-cap of the analog board.




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