Mac IIci dead SCSI?

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Lee Adamson's picture
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Mac IIci dead SCSI?

Hey folks!

 

So I recieved a IIci.  It is missing the snap-in hard drive bracket and had some kind of IBM "government property" SCSI drive just sitting in the space where the bracket is supposed to be.  This drive won't even spin up, and was jumpered to SCSI id 5.

 

I replaced it with an (untested) 20Mb Quantum drive out of a 20SC external enclosure, jumpered to SCSI id 1.  Machine starts up and goes to the "no system software found" question-mark disk.  I booted a System 7.1 disk tools floppy and ran HD SC Setup, and it is unable to find any devices on the SCSI bus.

 

Tried again with SCSI id set to 0, same thing.

 

I don't know the jumper settings to set termination on the drive, so that may have been the problem?

 

So then I took the drive (and cable) out entirely (thinking the lack of termination might be the trouble), and plugged a SCSI Zip-100 drive into the external SCSI port, set to SCSI id 5, and booted the disk tools floppy again.  Again, unable to find any devices on SCSI bus.

 

There is also no startup sound, presumably due to the leaky SMD electrolytics in the audio output section.  There is a little other capacitor funk here and there, but the battery hadn't leaked (I removed it).

 

Would a bad cap somewhere cause the SCSI bus to stop working?  If so, which one(s)?  I'll replace just enough caps to see if I can get SCSI working before I decide what to do.

 

If it's probably just caps, I'll keep it and fix it.  However, if it's a bad SCSI controller chip or something else equally dire, I'll try to send it back and get my money back (it was advertised as "tested" on the auction, which I guess just meant that "da gween light camed on").

 

Thanks folks.  I really appreciate the help.

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Lee Adamson wrote:

Would a bad cap somewhere cause the SCSI bus to stop working? 

 

Yes, but more importantly if it leaked it may have eaten through one or more traces on the circuit board. You could start by checking continuity of the traces around the affected area. If you find a break you'll have to remove the bad cap, give the board a thorough cleaning, and then add a jumper wire to restore the connection. And then of course replace the bad cap. I've done this several times to resurrect a dead machine but in your case unless you get the seller's permission to attempt the repair you might be better off just sending it back.

Lee Adamson's picture
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jeffmazur wrote:

Would a bad cap somewhere cause the SCSI bus to stop working? 

 

Yes, but more importantly if it leaked it may have eaten through one or more traces on the circuit board. You could start by checking continuity of the traces around the affected area. If you find a break you'll have to remove the bad cap, give the board a thorough cleaning, and then add a jumper wire to restore the connection. And then of course replace the bad cap. I've done this several times to resurrect a dead machine but in your case unless you get the seller's permission to attempt the repair you might be better off just sending it back.

 

Ahh, I'll just keep it and try to fix it.  It'll be a good learning experience.  :D  The network card, monitor, and all the RAM is probably worth what I paid for the machine, even if I eventually have to source a different mainboard.

 

Thanks!

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Does the 20MB drive you

Does the 20MB drive you tested with have an Apple logo on it anywhere? By default, the HD SC Setup program will only recognize and format drives with Apple firmware on them. If yours doesn't have the logo on it, the next easiest way to troubleshoot of SCSI is OK in your machine is to get a copy of SCSIProbe on your boot floppy. It can't format drives, but it'll show everything it detects on the SCSI bus, or if the bus has been left unterminated. If your drive shows up in SCSIProbe, then you have a few options for formatting it:

1. Track down a modified copy of HD SC Setup, where the Apple firmware limitation has been removed

2. Find a copy of LaCie Silverlining, a 3rd party Mac hard drive formatting utility (that works with non-Apple drives), or

3. Find a copy of FWB Hard Disk Toolkit, which does the same thing as Silverlining.

Good luck!

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Dr. Webster wrote: Does the

Does the 20MB drive you tested with have an Apple logo on it anywhere? By default, the HD SC Setup program will only recognize and format drives with Apple firmware on them.

Interesting, I was just investigating that!  It's a Quantum ProDrive LPS that came straight out of a closet-fresh 20SC external disk drive, so I *assumed* that it would have the Apple ROM in it.  BUT!  Now that I've gone and checked closer, I don't see the usual red apple sticker on it anywhere!  I was hoping that it would already have an HFS partition on it and would just magically show up, but perhaps it came off of an Apple IIgs or something and is full of ProDOS partitions!

I just tried (temporarily) replacing the SMD electrolytics near the SCSI IC and traces.  Didn't have any of the proper part, so temporarily soldered can electrolytics with the leads cut really short onto the pads.....  I'll fix it right when the proper parts arrive.

Here's a video showing what I've messed with so far.  Not mentioned is that all the onboard fuses check fine, as well as the diode (although I think it has something to do with the power on/off circuit, nothing to do with SCSI).

https://www.youtube.com/watch?v=AoIsaoJyb88

I've found some bootable Zip disk images for Systems 6.0 and 7.5, so I'm going to try dd-ing those to disk and see if they try to boot.  I am still dubious though, as in my testing so far the Zip drive has never even tried to seek during the boot process (as far as I can tell).

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Update:

Update:

 

I got the machine all working.  Recapped the rest of the mainboard.  Two pads were lifted.  :(  But there were vias nearby for bodge wires.  It doesn't look too awfully hacky I guess.....  Sound is working now, with the recap, so that's good.

 

Got the machine booting off a System 7.5 Zip disk image downloaded off the web.

 

I found limited docs on the SCSI drive that came in the machine.  2.0Gb Wide SCSI device.  I put a jumper on AS, but it still wouldn't spin up.  It doesn't even appear on the SCSI bus.  Dead I reckon.  I'll mess with it later.

 

The drive out of the 20SC case was actually a 50Mb drive, so it must not be original.  I was able to partition and initialize it with patched utilities off the Zip disk image.  No bracket to snap it into the disk drive holder, so I attached it with self-adhesive velcro pads.  <_<

 

It has some kind of Cableton Systems ethernet card installed, but I haven't looked for an extension for it yet.

 

After that I want to find a bigger drive and install A/UX.

 

Thanks y'all, for your advice.

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