Macintosh Classic Troubleshooting Help

[Moosen]

Hello all. I'm really at a loss with this machine, so hopefully some guru can help me out

I purchased a Macintosh Classic the other day for eight bucks, brought it home, plugged it in, and it booted up to a 'Welcome to Macintosh' Screen. However after it passed that it stalled and didn't do anything. So I restarted it a couple times, and still nothing. I instantly figured that it's installation was corrupted or the like, so i left it on (thinking it might just be taking some time to load) while I looked online for some system 6 install disks. It was only on (stuck at the welcome screen) for some 15 minutes.

The current symptoms are that the Macintosh Classic powers on, makes the start up sound, goes to a gray screen (with no cursor) and stops.
It did get to a screen with a cursor once on one random boot, but I haven't been able to get it to that screen again.

I have access to it's innards if that helps. I opened it up to check the cable connections, and tried replacing the internal battery.

edit:
I just noticed that the system seems to be continuously rebooting, after its on for about 45 seconds, the system makes the start up sound again, and the screen flickers slightly.

Any idea what could cause that?

 

[gr8tfly]

If there are any SIMMs installed, try reseating them.

If you can boot on a floppy that has Disk First Aid on it, use it to verify the install on the HD.

If you need them, I Apple has System 7 available online. (7.5.5 updater)

Good luck & enjoy!

edit: The rebooting could be caused by corruption on the HD. Hard to say on the slight flicker - it could be just a redraw thing or it could be the high-voltage supply (or, a bad ground, or - etc.). Hard to say without actually seeing it happen.

Just a note of caution: Not knowing your level of expertise working around CRT Macs (or CRTs in general), I thought I'd mention a few safety tips. Be very careful working inside. Even after the machine is powered off, there is high-voltage present. You should discharge the CRT (ground the anode - you can google for procedures). In general: stay away from the anode cable and connections (the one going into the side of the CRT), CRT itself, and the HV power supply. Work without jewelry. Only use one hand whenever possible - this reduces the possibility of current passing through your body, instead of only one hand.

 

[Moosen]

Thanks for the quick reply
I pulled the daughter board out, removed both SIMM's put them both back, then reinserted the daughter board. Still no luck, still seems to be stuck in some reboot cycle.

Also, can I create a mac boot up disk with a windows pc? I currently don't have access to a apple computer that works, and I am aware of differences between pc and mac floppies. If it comes to it, I can get a friend to make a floppy for me on his G4.

 

[gr8tfly]

Thanks for the quick reply
I pulled the daughter board out, removed both SIMM's put them both back, then reinserted the daughter board. Still no luck, still seems to be stuck in some reboot cycle.

Also, can I create a mac boot up disk with a windows pc? I currently don't have access to a apple computer that works, and I am aware of differences between pc and mac floppies. If it comes to it, I can get a friend to make a floppy for me on his G4.

I can't remember if I ever tried getting the "bin" images copied on a PC. My feeling is you will have the least amount of trouble doing this by borrowing your friends G4.

 

[Moosen]

Just a note of caution: Not knowing your level of expertise working around CRT Macs (or CRTs in general), I thought I'd mention a few safety tips. Be very careful working inside. Even after the machine is powered off, there is high-voltage present. You should discharge the CRT (ground the anode - you can google for procedures). In general: stay away from the anode cable and connections (the one going into the side of the CRT), CRT itself, and the HV power supply. Work without jewelry. Only use one hand whenever possible - this reduces the possibility of current passing through your body, instead of only one hand.

I appreciate the advice I have a bit of experience with CRT's myself, yet still exercise extreme caution when it comes to working around them. I'm definitely open to safety tips.

To your comment on the screen, I'm fairly certain it has to do with a refresh like you mentioned. Its so brief that it's almost unnoticeable. Also, I read that the Macintosh Classic has a copy of System 6 on ROM that can be booted. If I was to unplug the hard disk, shouldn't I be able to boot into that without needing any boot disks?

 

[gr8tfly]

I appreciate the advice I have a bit of experience with CRT's myself, yet still exercise extreme caution when it comes to working around them. I'm definitely open to safety tips.

To your comment on the screen, I'm fairly certain it has to do with a refresh like you mentioned. Its so brief that it's almost unnoticeable. Also, I read that the Macintosh Classic has a copy of System 6 on ROM that can be booted. If I was to unplug the hard disk, shouldn't I be able to boot into that without needing any boot disks?

Interesting - I didn't know that model had that. I checked MacTracker, and sure enough it does mention a 512k bootable ROM. To boot: "The Mac Classic could be booted into System 6.0.3 by holding down the Command + Option + X + O keys during boot." (from wiki)

 

[Moosen]

Alright, I tried the shortcut, with and without the hard drive plugged in, and still no luck. In both cases the system continuously rebooted after a few seconds with nothing on its screen. Also out of the blue, with everything plugged in, it booted to the gray screen with the cursor shown, then locked up again. I tried restarting the Macintosh without touching anything else and it just went back into the reboot cycle. Unfortunately I also wasn't holding down the boot option shortcut keys on that boot.

These random 'look i started to boot' instances make me think it has to be something I can fix, and that it's not just fried out.
The ironic thing is that the rebooting and chimes sounds an awful lot like a heart monitor