Does anyone know if the RTC chip on the SE/30 fails often? Something on the RTC circuit has failed as System 6 boots fine but System 7 always fails to boot. Already replaced the crystal oscillator to no avail. Part number is 343-0042-B. UTsource has them. Or does another macintosh use the same chip that i could steal it from and test it. Or should i check something else totally different? Any help would be appreciated.
SE/30 RTC issues
- Thread starter Duke09
- Start date
In what sense does it fail to boot, and why would you suspect the RTC specifically? (As opposed to the numerous other things that could be wrong)
Well system 6 boots perfectly fine, and system 7 will either hang on welcome to this macintosh or throw a system bomb error. I was told by someone else system 6 doesn’t require the RTC to work but system 7 does, so that’s why o believe the RTC circuit is bad.
I've never (personally) seen an RTC chip fail in this way. Actually you can boot System 7.5 (or any system) without an RTC chip installed, you just won't be able to boot off a SCSI drive.
You'll have to do more investigation before you can begin to make any conclusions about what's faulty. I don't think it's necessarily the RTC circuit.
Are you trying to run system 7.1, or 7.5? Do you have a custom ROM installed? Have you tried different RAM? Have you tried booting off a disk tools floppy? Have you tried reinstalling the OS? Is the logic board recapped? Any other custom stuff, peripherals or upgrades? These are the first questions I'd ask.
You'll have to do more investigation before you can begin to make any conclusions about what's faulty. I don't think it's necessarily the RTC circuit.
Are you trying to run system 7.1, or 7.5? Do you have a custom ROM installed? Have you tried different RAM? Have you tried booting off a disk tools floppy? Have you tried reinstalling the OS? Is the logic board recapped? Any other custom stuff, peripherals or upgrades? These are the first questions I'd ask.
Ive tried a bunch of different known working scsi hard drives. stock ROM simm. I’ve tried different ram. I believe it fails to boot off syste 7 floppies as well, system 6 ones work iirc. I recently just got some blue scsi so it will be easier to test now.
I recapped it long ago, all SMD and axiels. Also replaced the scsi chip and fixed bad traces around the scsi chip.
Can you make a boot floppy on another Mac with MacTest Pro, and boot off that? I believe there are System 6 versions.
Then run all the hardware tests and see if it comes back with anything.
If you're convinced the problem is in the RTC area, I'd have a look at the VIA chip which is connected to the RTC circuit. I had one which was faulty and it caused some really weird behaviour. You can get modern replacements off Mouser if one of those has gone bad. Also see what happens if you remove the RTC chip.
Then run all the hardware tests and see if it comes back with anything.
If you're convinced the problem is in the RTC area, I'd have a look at the VIA chip which is connected to the RTC circuit. I had one which was faulty and it caused some really weird behaviour. You can get modern replacements off Mouser if one of those has gone bad. Also see what happens if you remove the RTC chip.
Yeah I can give that a go. I’ve also thought about using snooper. I can load both those onto a system 6 version and give both a try.
So you've had the board a while, and it was working previously, and now all of a sudden it doesn't work properly?
Yeah Ive had it for a few years. When I initially got it, it was fine. I recapped it a bit later and it was still good. Then after awhile once the recapping was done it would only boot sometimes off the 7.5.3 hard drive, then stopped all together. It only works 100 percent of the time off system 6.
Just read it now. I’m not familiar with the VIA chip but I’ll look for it when I get around to it tonight. What part of the board is it at?
My quick scan of this thread for the first time today suggests that @Duke09 is only "guessing" the RTC is bad based on advice given by others about how System 6 responds to a bad RTC versus System 7. But if the RTC is bad, it should be easy to test merely by putting in a good PRAM battery, booting into System 6, setting date/time, shutdown, yank the power cord for 24 hours, then plug it in, power on and boot. If the Date/Time is 100% correct one day later with the power cord out that whole time, I don't see how the RTC could be bad.
Now if that date/time was done and it was determined the date/time do NOT get saved (with PRAM battery installed) after power is gone, then swapping out the RTC is necessary. If you did swap out the RTC and that didn't help (date/time still not saved), then and only then would I suggest looking at all connections that lead to/from the RTC, and you'll need the freely available SE/30 motherboard schematics (BOMARC and Apple) to do that.
Now if that date/time was done and it was determined the date/time do NOT get saved (with PRAM battery installed) after power is gone, then swapping out the RTC is necessary. If you did swap out the RTC and that didn't help (date/time still not saved), then and only then would I suggest looking at all connections that lead to/from the RTC, and you'll need the freely available SE/30 motherboard schematics (BOMARC and Apple) to do that.
Well the issue is System 7 will not boot at all. It was suggested to me by someone else that System 7 needs a working RTC circuit unlike system 6, not sure if that is true. But I am still stumped on why it will not boot into any version of System 7 I’ve tried, it either hangs onto Welcome to this Macintosh or has a system bomb of some sort.