I'd love a copy of your diagram if you still have it!

Some LC475 run stable at 40MHz just as they are. Why not try it before you get a large 840av? And when it works, treat yourself by getting a new 840av. ;D

from the link above: I changed MC88920 to MC88916DW80, and my LC475 is working at 42Mhz perfectly. Higher clock causes unuseable serial ports (Ummm---regrettable). Click …

There's another simpler way to get to 40 MHz which used to be available from here:http://gabezing.sytes.net/LC475-40Mhz-E.html However, that site's been unavailable for a while an…

My SE/30 SCSi problem has been fixed!! The via connecting pin 25 of the SCSI chip to pin 9 of the SWIM chip was corroded by leaked capacitor fluids and was no longer conducting. …

TERMPWR checks out good (+5V) on both the internal and external SCSI connectors. I actually checked it at each of the inductors first and finally at the connectors themselves. I …

if you have no TERMPOWER, that means your fuse or inductor feeding the SCSI bus and/or IC is open circuit. Testing and replacement will bring the bus alive.

Z53C80 and NCR53C80 are the same part from different manufacturers. Often, one manufacturer will license the part from another. In some cases, they develop the part independently…

techknight, If i did my research correctly, I should have seen +5V across pins 24 and 25 of the external DB25 connector if the SCSI bus were working correctly. Unfortunately, I me…

techknight, thanks for weighing in. Your videos were very helpful in getting me rolling, but I'm afraid I'm lacking background information to act on your current suggestion. What…

check to make sure you have termpower at the DB25 connector as well. if not, theres the issue.

ixnay on the ematicschay request. I just realized that zuiko21 gave me the logic board connections for the 53C80 in the link in his response. I thought it was a pix of his board …

Cool. The symptoms were very similar to my problem, but on your board, the software at least detected that something was out there. On mine, SCSIProbe just blinks "SCSI Bus Not T…

That was my board in the video. It would boot up to the question mark, but wouldn't recognize any SCSI devices whatsoever. He fixed the bad connection and it works great now.

Gents, thanks for the quick update. Just got done watching about 4 of TheTechKnight's Youtube videos on resolving SE/30 problems to see if I could learn more. He also had a SCSi …

The link to the 53C80 datasheet has changed from to http://www.prismnet.com/~trag/DataSheet/Z53C80.pdf Basically, anywhere I ever used io.com, it is now prismnet.com. I wish I …

Hi! It's the DB2 line, between pin 39 on the 53C80 chip (the uppermost pin on the right side) and pin 6 on the IDC-50 internal SCSI connector. It's also connected to pin 22 on the…

zuiko21, Which connection was broken? The problem you encountered is VERY similar to what I'm trying to resolve on my newly recapped SE/30 (my system reports that the SCSI Bus is…

Hm. I have a post September 10th 128k-model board in my Macintosh 128k (but with an original Macintosh rear bucket), Apple branded RAM chips, stock 128k amount even, not a single c…

Finally.... MISSION COMPLETED!!!!!!!!!!!!!!!!!!!!!!!!! Got a 80GB 5400RPM HDD today to replace the problematic 10GB HDD in the iBook. After spending all afternoon taking the HDD o…

disk0 is going to be the hard drive. You're getting hard drive errors there. You may want to boot it into firewire target mode and do a surface scan on the disk from another comput…

disk0 is going to be the hard drive. You're getting hard drive errors there. You may want to boot it into firewire target mode and do a surface scan on the disk from another comput…

OK: Update. I tried resetting the PRAM. Nothing. Wouldn't boot in safe mode either. I booted from Verbose mode. I got the following (it hangs here): ATIRage128: Using AGP Airpo…

@FlyingToaster, After I got the kernel panic I tried the Apple Hardware Test CD for the iBook. I did the long version, which took about 15 minutes and it stated that everything pas…

You can maybe try an apple hardware test cd. It depends on if it works on your ibook or not, some models it doesn't support. I think it has a long RAM test on it, maybe leave it l…