Gents,
Thanks for all the suggestions. Have not yet received the hard drive so can't confirm if a different drive fixes the problem, but can address some of your posts:
1. Original caps looked very good, but for giggles I did recap all but two of them (I didn't have tantalums in the right capacitance for those two). No change to boot up process.
2. I am also concerned that the new drive may not boot since I can't get the Zip to boot, but I didn't see many other simple-to-test options.
3. I tried to boot with extensions off; welcome screen confirmed that extensions were off, but boot froze anyway.
4. It does have a network card; I tried booting with and without it thinking that it may be the problem, but no joy.
5. I burned the 7.5.3 CD using the Apple downloads (all 19 parts) that day. Didn't get any error messages, but that doesn't mean it was perfect. However, I noted that the boot process froze in identical fashion AFTER installing the new 7.5.3, i.e. the original (previously good) installation failed in the same manner so I don't believe the system software is the cause.
6. I'm still concerned about the SCSI chip, but I find it really strange that I can access all SCSI drives successfully if I boot from floppy. I did numerous file transfers (to and from the hard drive and the Zip) and ultimately reinitialized the hard drive, all successfully. So if it is the SCSI chip it must be in a function unique to the boot up process. Unfortunately, I don't know the hardware boot sequence well enough to even speculate any farther on possible faults.
7. I thought about trying to rebuild the desktop file, but couldn't remember the key code combination. If I remember correctly, however, that process occurs near the end of the boot process, about the time the desktop appears. If so, I never got to that sequence anyway. Further, reiniting the drive and installing the system software should have addressed that issue if it were the problem.
Thanks again for taking the time to provide advice. I'll update the post once I test with a different SCSI drive. I'm hoping (perhaps vainly) that the hard drive will be the source of the problem since replacing an IC on the board is beyond my soldering tools and capability.
P.S. I am curious about the concept of heating up the SCSI chip for test. My previous exchanges with guys who troubleshoot circuit boards normally recommended using aerosol sprays that cool the traces since that will improve conductivity (until it heats back up) and allow you to verify if a bad solder joint exists. Has anyone had success with the heating components to troubleshoot on-board problems?
Thanks for all the suggestions. Have not yet received the hard drive so can't confirm if a different drive fixes the problem, but can address some of your posts:
1. Original caps looked very good, but for giggles I did recap all but two of them (I didn't have tantalums in the right capacitance for those two). No change to boot up process.
2. I am also concerned that the new drive may not boot since I can't get the Zip to boot, but I didn't see many other simple-to-test options.
3. I tried to boot with extensions off; welcome screen confirmed that extensions were off, but boot froze anyway.
4. It does have a network card; I tried booting with and without it thinking that it may be the problem, but no joy.
5. I burned the 7.5.3 CD using the Apple downloads (all 19 parts) that day. Didn't get any error messages, but that doesn't mean it was perfect. However, I noted that the boot process froze in identical fashion AFTER installing the new 7.5.3, i.e. the original (previously good) installation failed in the same manner so I don't believe the system software is the cause.
6. I'm still concerned about the SCSI chip, but I find it really strange that I can access all SCSI drives successfully if I boot from floppy. I did numerous file transfers (to and from the hard drive and the Zip) and ultimately reinitialized the hard drive, all successfully. So if it is the SCSI chip it must be in a function unique to the boot up process. Unfortunately, I don't know the hardware boot sequence well enough to even speculate any farther on possible faults.
7. I thought about trying to rebuild the desktop file, but couldn't remember the key code combination. If I remember correctly, however, that process occurs near the end of the boot process, about the time the desktop appears. If so, I never got to that sequence anyway. Further, reiniting the drive and installing the system software should have addressed that issue if it were the problem.
Thanks again for taking the time to provide advice. I'll update the post once I test with a different SCSI drive. I'm hoping (perhaps vainly) that the hard drive will be the source of the problem since replacing an IC on the board is beyond my soldering tools and capability.
P.S. I am curious about the concept of heating up the SCSI chip for test. My previous exchanges with guys who troubleshoot circuit boards normally recommended using aerosol sprays that cool the traces since that will improve conductivity (until it heats back up) and allow you to verify if a bad solder joint exists. Has anyone had success with the heating components to troubleshoot on-board problems?