68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.
Quadra 605 freezing w/copying large files
Posted by: Byte Knight on 2023-09-27 18:26:17 Hey guys, My Quadra 605 w/BlueSCSI v2 running System 7.5.5 freezes up intermittently when I'm copying large files between hard drives or from my server. I thought this might be from overclocking the logic board to 33 MHz, but it never freezes with copying when all extensions are off. I've tried shutting off all suspect extensions and control panels without any luck. Anyone else run into this problem?
Posted by: MrFahrenheit on 2023-09-27 20:18:54 Ok this is really interesting. In April I was doing some large file copying on my Q605 and ran into the exact same problem. And it didn’t matter if I removed the jumper to make it a 475 or not. Mine is also overclocked and I was also running 7.5.5. I also recapped mind with tantalums. The freezes were random. After a minute, or 10 minutes or an hour. Just … random.
Posted by: Byte Knight on 2023-09-28 10:55:16 Ok this is really interesting. In April I was doing some large file copying on my Q605 and ran into the exact same problem. And it didn’t matter if I removed the jumper to make it a 475 or not. Mine is also overclocked and I was also running 7.5.5. I also recapped mind with tantalums. The freezes were random. After a minute, or 10 minutes or an hour. Just … random. When you have some time, try copying some CD-size files and see if it happens regularly. Then try it with extensions off.
Posted by: Phipli on 2023-09-28 11:01:09 When you overclock to 33MHz, you're also overclocking the SCSI chip... Try moving the zero ohm resistor at R96 to the R95 position and see if it helps. @Byte Knight @MrFahrenheit This divides the clock to the SCSI chip to a lower speed and back within spec if my beep beep beeping is right. Spent far too much time looking at the MC88920 chip lately.
Posted by: Byte Knight on 2023-09-28 11:11:05 When you overclock to 33MHz, you're also overclocking the SCSI chip... Try moving the zero ohm resistor at R96 to the R95 position and see if it helps. @Byte Knight @MrFahrenheit Thanks for the tip - will check it out!
Posted by: MrFahrenheit on 2023-09-28 17:27:31 When you overclock to 33MHz, you're also overclocking the SCSI chip... Try moving the zero ohm resistor at R96 to the R95 position and see if it helps. @Byte Knight @MrFahrenheit This divides the clock to the SCSI chip to a lower speed and back within spec if my beep beep beeping is right. Spent far too much time looking at the MC88920 chip lately. View attachment 62754 Yes, thank you @Phipli for discovering and sharing this!
Posted by: Phipli on 2023-09-28 17:30:16 Yes, thank you @Phipli for discovering and sharing this! With the help of others 🙂
Posted by: Byte Knight on 2023-09-29 16:40:04 That fixed it - thank you so much!!
Posted by: Phipli on 2023-09-29 16:59:28 That fixed it - thank you so much!! Brilliant news. We need to remember this fix if others are having the same issue in the future!
Posted by: croissantking on 2023-10-31 06:11:48 Brilliant news. We need to remember this fix if others are having the same issue in the future! Would be good to collate all our wisdom into some kind of publication, not sure the forums are safe in the long term as they have had crashes in the past.
Posted by: Phipli on 2023-10-31 06:22:06 Would be good to collate all our wisdom into some kind of publication, not sure the forums are safe in the long term as they have had crashes in the past. Well, I mean, this is why descriptive thread names are important, but people don't seem to bother with that these days. Lately I've seen things like "Another question". How on earth are you meant to find that thread by searching? I should write more stuff up for my site, but remember it takes time, so I need to be motivated to do it. Same for other people. There is hours in writing anything up properly.
1