SE/30 refuses to boot all of a sudden - dead SCSI circuitry?

[Blougram]

Hello everyone, I'm new to this forum, and thought a short introduction might be in order:

I received a used Mac SE on my eleventh birthday in 1992, and fell in love with the little beast. The keyboard, the sleek design - almost retro by 1992 standards - and the smiley face! I used it extensively for homework, creative writing and some simple BASIC programming. Not to mention the games, of course. Unfortunately, it was soon given the Toy Story III treatment, stowed away into a cardboard box in the attic. In its place a new 80486, a Pentium MMX... I would plug it in on occasion for a round of Shufflepuck or some tapping away in WriteNow. Aw, that clickety-clackety keyboard! To make a long story short(er), a few years ago my mom called me and asked if I wanted to keep that old computer gathering dust in the attic. I gave her the go-ahead, and it was duly sent to the recycle station.

I missed it, and tried to fill the void with Basilisk, Mini vMac on my iPod and whatnot, but it just wasn't the same. So when I saw an ad for the real thing some weeks ago - a Macintosh SE/30 20/110 with an Ethernet card, external SCSI HD and CD ROM - well, I didn't think twice.

And now to my problem. It worked like a charm for a few days, until it crashed while I was checking my internal HD with Norton Tools and booted with the dreaded question mark. Things wouldn't have been that bad if it was only a dead HD (I have a back-up on the the external one), but the problem is, it also refuses to boot from the external SCSI HD. I made a few boot floppies with WinImage on my Windows XP machine, but most of them refused to boot (the computer freezes during the Welcome Screen). In the end, though, I managed to get it up and running with the first install floppy for System 6. But I still cannot access the hard disks. HD SC Setup (which was on the floppy) does not find any SCSI devices

I knew the PRAM battery was dead (apparently it had been dead for months, but the computer had booted up with no problems) so I decided to replace it, having no idea that I had to dislodge the logic board in order to do so. Due to my innate clumsiness and, well, being technically challenged, I have always stayed away from hardware. Thanks to an instructive PDF file from Apple, though, I managed to slide it out. There was no battery or capacitor leakage to speak of (I removed a tiny amount of gooey substance next to C13 with a toothbrush). I replaced the battery, and tried booting again. Still the blinking question mark. I tried disconnecting the cables from the internal HD in case it was disrupting the SCSI chain, but I still get the blinking question mark. And it still refuses to boot from the external HD.

So, my question is: is it possible that the SCSI circuitry has failed all of a sudden? According to most web sources, this would normally lead to a rastered gray background and a cursor, without the blinking question mark. I will replace the internal HD, but I am worried about the fact that the computer cannot find any SCSI devices.

Any ideas?

 

[bigmessowires]

I was recently working on a friend's SE/30 that had the exact same problem. The HD was working, then suddenly it wasn't, and neither was external SCSI. Booting from floppy was fine. His sound was also very quiet, even at the loudest volume setting.

In his case, we decided that some of the board traces around the SCSI chip had been damaged by capacitor leakage. This may be more subtle-looking than you were expecting. I know I was expecting "leakage" to be some obvious-looking pool of battery acid, but in fact it's just a hard-to-notice area that looks a little grainy and reflects light differently than other areas.

 

[Blougram]

Thanks! I will take a closer look at the logic board.

When booting the internal hard disk makes a high-pitched whining sound for a few seconds and then stops. The LED flashes a few times. I thought this was due to the fact the the disk was being powered, but when I disconnect the data cable (leaving the power one connected) it makes no sound whatsoever, and the LED is constantly on. Perhaps this would suggest a hard disk failure, but can a crashed/dead internal disk disrupt a whole SCSI chain? As I mentioned earlier, the external hard disk is still not recognized even when the internal one is disconnected.

 

[Blougram]

To put my question more clearly, would a crashed internal hard disk disrupt the SCSI chain so that it is no longer terminated at the "internal" end? The upshot being that I would have to add a terminator to the SCSI connector on the logic board in order to use any external devices? As is suggested here http://support.apple.com/kb/TA27743?viewlocale=en_US.

Like this, I guess:

I will try to get hold of a replacement hard disk (or lift the external one from its enclosure), but before I perform surgery I would like to know if this (i.e. no internal termination) is a possible explanation for the fact that the computer does not recognize any external SCSI devices.

Why is it called a "daisy chain" anyway? It's not like all the other flowers in the garland will suddenly wither if you pluck one of them.

 

[bigmessowires]

I'm not certain, but I doubt a defective internal hard drive would cause external hard drive failures.

If you disconnect the internal hard drive, then you'll loose the internal SCSI termination, but your external SCSI drive will still be terminated. According to Apple's Macintosh Family Hardware Reference, a SCSI chain containing only a single device with less than 3 feet of total cable length only needs a single terminator.

 

[Blougram]

Ah, so I guess it might be my SCSI controller, then.

I managed to put a few SCSI tools on my 6.0.8 start floppy, and the IDs of my external devices show up in a very early version (1987) of SCSI Probe, but I'm not able to mount the external hard disk. With Mount Everything (a misnomer, if ever I heard one) the IDs are not explicitly detected, but the scanning process pauses for a few seconds at the IDs on which I have the devices. So, there is some kind of data transfer through the SCSI bus. Unfortunately I'm stuck with very outdated utilities since the computer refuses to boot System 7 from a floppy.

 

[bigmessowires]

Interesting, those are virtually the identical symptoms of my friend's SE/30, and the same software tools we tried. If you ever figure out the root cause for certain, I'd love to know!

 

[JDW]

But WHY would the SCSI controller suddenly die? I agree with the advice already given. Leaked capacitor fluid is most likely the culprit, and you should not proceed with anything else until you have verified that and eliminated that problem completely -- the details of which have been discussed here in other threads many times.

I dare say there is not one SE/30 in operation today which does not need it's board cleaned of leaked fluid and capacitors replaced.

 

[phreakout]

The 53C80 SCSI Controller chip (UI12) can go bad, and when it does, it gives you this symptom. Luckily, you can buy replacements for under $10 apiece, but you'll need the proper hot air rework solder/desolder workstation to swap out the bad part. I don't have one of those workstations and am diligently trying to wire up the chip with enamel coated wire running from each pad to their respective leads on the IC. A pain, but am making progress; I'll keep everyone posted and with pics as to how it turns out.

Apparently, silicon does go bad after so many years and no amount of recapping can fix the problem. It may be even more serious enough to spread to the other components on the top or bottom of the logic board. But this depends on storage environment, how often it's powered up, age of the Mac, etc.

Another item to try replacing is the Bourns network filters (RP2, RP3 and RP10), maybe check the fuses (F3 & F2), diode (D3), Serial Controller Chip 8530 (UG12), not to mention the various resistors, capacitors, diodes and inductors on the underside of the logic board. So I'm talking that in some cases, you may have to go as far as totally rebuilding your logic board to fix an issue like this, but in other cases you may just have to replace UI12.

Then again, it could be as simple as bad data cables or termination that isn't right.

73s de Phreakout. :rambo:

 

[bigmessowires]

you'll need the proper hot air rework solder/desolder workstation to swap out the bad part

I've never tried it, but there's a special desoldering alloy called Chip Quik which lets you desolder ICs with a normal soldering iron. It has a very low melting temperature, so you can apply it to all the pads in turn with your iron, and they will stay molten long enough for you to reach all the pins and remove the part.

The guy in this video used it to desolder a 160 pin chip from a Nintendo 64:

 

[techknight]

silicon only degrades because of the prolonged exposure to moisture, im not a chemist so i dont know the process, but i do know that it happens.

this is why when electronics are stored away for a long time, such as HDDs, or IC chips, they are stored vacuum sealed with silica gel to pull out the moisture and keep it out.

Eventually every IC will fail on every logic board known in existence. it just depends on how well the chip is sealed away from the moisture. any porous chips will degrade faster than others. Is epoxy porous and will it absorb moisture and eventually get to the silicon die? I dunno but apparently so or they wouldnt ship certain ICs with silica gel.

 

[JDW]

From what I understand, even Cosmic Rays can affect the life of silicon chips. But what we all want to know is, exactly how many years will silicon chips last on average? And will that exceed a human life span? It would appear one of you with library access would need to consult this book for the possible answer to that very question:

http://resources.metapress.com/pdf-preview.axd?code=v166l810q7527310&size=largest

 

[techknight]

Yea, thats what i want to read. curiosity is kicking. hehe.

 

[Blougram]

Silicon senescence? I like where this discussion is heading!

I tried to install my external hard disk in my SE/30; still no luck, but this might be because of the jumper settings.

Help with deciphering this ascii diagram would be much appreciated: http://stason.org/TULARC/pc/hard-drives-hdd/conner/CFP-1080S-1080MB-3-5-SL-SCSI2-FAST.html - as I understand it, S1-S3 should be without jumpers for ID 0. Right?

 

[JDW]

Silicon senescence? I like where this discussion is heading!

Actually, this discussion is headed no where unless one of you gents in the US heads to your local library and checks out that book I linked for you. If I were in the states, I would certainly do such on one of my days off. But here in Japan, I have no library access to English books, other than the likes of Dr. Seuss. I wasn't able to dig up anything online either, although I only Googled for about 30 minutes.

Since this is a Vintage Computing forum, I think the topic of "silicon chip aging" is quite relevant for all of us, albeit not the main thrust of this particular thread.

 

[Blougram]

Turns out I have access to the database. I could post the full PDF file, but I'm sure that would constitute a heinous act of copyright infringement. PM me and I'll send you a copy. In the meantime, perhaps someone could take a quick look at the ASCII diagram I linked to.

 

[phreakout]

Sorry if I took this thread off topic. But I was only stating the facts, in hope that the others out there would come to their own conclusions for a decent answer. Now that we know it takes thousands of years before silicon is effectively no good (not figuring in moisture affecting the age), I can doubt that even these Macs will still be in service that far down the road. I think they'll be museum pieces by then.

Anyway, back to the topics at hand: SCSI issues. Blougram, that is correct, regarding S1 through S3. If that doesn't work, try SCSI ID #1 or #6. Apparently, if I'm reading it right, that model drive seems to like having termination enabled on the odd ID numbers. Strange.

73s de Phreakout. :rambo: