macintoshportable
Member
Hi I'm restoring a Portable and have recapped. Everything works perfectly now except as soon as the system tries to read a disk the whole system crashed.
A bit of research suggested the SWIM chip and some times the SWIM clock are to blame. I have a dead LC board with the same chip that I could use but I thought someone might know a bit more before I attempt a switch over.
My question is
Does anyone know how I would test the SWIM chip/clock and track down the cause of this issue?
A few more details and observations
If I try to boot from floppy (or floppy emu) it's an instant sad mac usually returning 0000000F 0000000A or in sad mac codes 'Class Code F = Exception' 'Sub Code 000A = Line 1111'
If booted to the internal SCSI drive I get the bomb message with 'Bad F-line instruction' and a restart button on read, however I can't click it as the system is locked up.
Recap details
- All electrolytic caps were changed
- The board was ultrasonically cleaned with the correct solution and demineralised water
- Then soaked in IPA and dried with warm air
Fails in the following configurations
- Running on a 6V 4.5AH sealed lead acid battery with new 9V backup battery
- Running on an original white charger that still outputs the correct voltage, with the batteries installed as described
- With the original floppy drive installed
- With a floppy emu installed internally with the floppy drive
- With a floppy emu installed externally with the floppy drive
- With a floppy emu installed without the drive on floppy 1, 2 and external
Other notes
- The emu has been tested on another machine and works fine
- I checked the surface temp of the SWIM chip and it's running at about 30C/86F while everything else is running at about 20C/68F.
- The emu does strange things when the power adapter is plugged in. Fails to 'read disks', random things on screen, can't find SD card etc. Run it on battery and it's all good again.
- It looked like some of the through-hole caps had been changed before but I changed them all again as the electrolytic smts hadn't been changed. I'm suspect on a few of vias C3, C6 and C2 weren't in the best condition and though I was careful I can't be sure I didn't make them worse, except that the rest of the system seems to run indicating all is ok.
Any help would be greatly appreciated!
A bit of research suggested the SWIM chip and some times the SWIM clock are to blame. I have a dead LC board with the same chip that I could use but I thought someone might know a bit more before I attempt a switch over.
My question is
Does anyone know how I would test the SWIM chip/clock and track down the cause of this issue?
A few more details and observations
If I try to boot from floppy (or floppy emu) it's an instant sad mac usually returning 0000000F 0000000A or in sad mac codes 'Class Code F = Exception' 'Sub Code 000A = Line 1111'
If booted to the internal SCSI drive I get the bomb message with 'Bad F-line instruction' and a restart button on read, however I can't click it as the system is locked up.
Recap details
- All electrolytic caps were changed
- The board was ultrasonically cleaned with the correct solution and demineralised water
- Then soaked in IPA and dried with warm air
Fails in the following configurations
- Running on a 6V 4.5AH sealed lead acid battery with new 9V backup battery
- Running on an original white charger that still outputs the correct voltage, with the batteries installed as described
- With the original floppy drive installed
- With a floppy emu installed internally with the floppy drive
- With a floppy emu installed externally with the floppy drive
- With a floppy emu installed without the drive on floppy 1, 2 and external
Other notes
- The emu has been tested on another machine and works fine
- I checked the surface temp of the SWIM chip and it's running at about 30C/86F while everything else is running at about 20C/68F.
- The emu does strange things when the power adapter is plugged in. Fails to 'read disks', random things on screen, can't find SD card etc. Run it on battery and it's all good again.
- It looked like some of the through-hole caps had been changed before but I changed them all again as the electrolytic smts hadn't been changed. I'm suspect on a few of vias C3, C6 and C2 weren't in the best condition and though I was careful I can't be sure I didn't make them worse, except that the rest of the system seems to run indicating all is ok.
Any help would be greatly appreciated!