Color Classic Internal SCSI

take extra care cleaning the edge connector... those can drive me nuts sometimes...  clean both sides really good.

Thanks.  That was my first step, and I tried again now but it's looking like a no.  I fear it's something closer to this: https://68kmla.org/forums/index.php?/topic/11963-mac-se30-scsi-problem/#p151547, but I don't exactly know what the equivalent is since there's no (direct) internal 50pin connector in the CC.  The board is in good shape; the only obvious trace issue is that the laminant came off a small part of a trace totally unrelated to this - I don't think that's an or the issue.

But I don't think I have the know-how to debug this the way TjLazer did his SE/30.  However, I don't think it's the 85C80 [overall] since that'd mess with external SCSI and serial.  So I guess I should test serial.  If this is a pin connection [i.e. a component of the 85C80] issue, it'd be such in a way that only the internal is affected.

*I also forgot to mention that the CC has a MicroMac 32mhz 68030 PDS upgrade, but removing it/leaving it in has had no effect.  (When I booted from the original drive as an external, I inadvertently confirmed that the card is working).

Here's another thought.  It actually might be a problem with one of the three capacitors by the contacts (between the board and inside the case).  The external SCSI works; and the 85C80 microprocessor is directly below the external SCSI port so that's maybe not surprising.  The rest of that MP's leads mostly go down the board and then through it, then over toward/to those capacitors. [C9 / C10 / C11]
 
I tried to reflow the solder thinking maybe that'd be a quick fix, but no dice.  I might have those particular caps on hand but I'm not prepared to do the job tonight, and I'm a little uncomfortable if that solder really won't flow readily.  I don't have a lot of boards to play around with.

So you didn't change all the caps?

I didn't recap it at all.  I've had trouble finding documentation on CC cap issues, and I haven't run across anything that would indicate a specific connection between SCSI issues and caps until this: http://www.vintage-computer.com/vcforum/showthread.php?50463-Color-Classic-Internal-SCSI.  I haven't had that problem elsewhere.

re-cap er.   its absolutely needed.  then SCSI will work.

It could be a power supply issue.  The older a SCSI drive is, in general, the more power it requires.  With a CPU accelerator in there as well, you might be coming up to the limits of what an aging power supply can put out.

Try mounting the drive in a powered external SCSI box if you have one and see if you can get the machine to boot.

That was one of my thoughts too, Bunsen.  I think I noted above that it and another drive both boot the CC from an enclosure, but neither boots from inside.  The other drive (not the Apple-branded IBM) clicks as if the head is hitting something inside.  And that also made me think either some failure in the data line or power; but I don't know how to diagnose which, further.

Is the CC power supply similar/identical to another I can try*?  Is it similar to LC/LC II?  I recently recapped those, so I'm thinking of trying the drive internally in an LC. I've already ordered caps for the CC, but I'd rather not mess with the motherboard if that's not actually the problem.

*I mean I guess that's actually not likely to be relevant since neither has to actually drive a CRT, and neither has an analog board.  Maybe I should try it in my SE/30 that I know has resistor problems on its analog board.

The CC analog/power board is most similar to a Performa 520, 550 or 57x series machine, and even though they're not physically interchangeable without some work, they are more or less electrically compatible, and you should be able to simply shove a CC logic board into either a P520 or P550 and have it just work, since the P520/P550 boards work without modifications in the CC (not 100% sure about the 57x, but I don't see why not). This assumes you have, or can gain, access to a P520/550/57x, of course.

LCs and the SE/SE30, on the other hand, are *NOT* compatible with the CC in any way, so don't even bother.

c

Oh, and problem or not, you NEED to recap that CC board ASAP, before it becomes a problem.

It's a matter of preventative maintenance, and if it's more or less working as is, that's the time to do it, because a simple recap isn't as likely to bring back a board after it stops working, as the damage has likely already been done*.

c

*Such boards *CAN* usually be brought back, but it's not as straightforward, and success is not always certain. The Quadra 840av is a prime example-- to my knowledge, nobody has been able to reliably bring them back once they're dead, yet.

Yeah I don't have those so that's not really an option.  Can I measure the voltage/amperage somewhere easily? 

And my thought on recapping has been that there isn't really a destructive end - that if caps die, I'll replace them, but if not then the worst case is they die and I have to replace them.  I guess I'm just more comfortable with the idea of necessary repair rather than preventive maintenance.  Am I way off?  Can short-term cap goo exposure destroy boards?

Replacing the bottom three caps (C9/10/11) had no effect.

(I'm also still not clear on the necessity of recapping.  For a site so dedicated to that mainstay, I'm surprised nobody is able to justify the logic.)

please take a picture of your cc main board, post.   Well let, Good Focus, Good resolution.

Thanks.

I can't tell you how many CC's i have got in, with a note that that says, (All works except for internal scsi).

After a Full De-cap,  Clean, Wash, Re-cap.  IT then works.

I speak from absolute experience.

Hmmm... then maybe I should wash it again. I thought about that before recapping. I'll finish the recap but I'm also curious to pinpoint the issue. Is this high resolution enough (the Galaxy Note 3's cam isn't great*)? And it's not the cleanest/prettiest solder job I've done, but I don't think that's the (/an) issue.

*I'm actually not sure I can do better.  I apologize.

To answer your question about cap goo, yes, it can absolutely destroy a board without notice. All you need for it to do is eat into a couple of traces, which is accelerated by the presence of heat and electrification of the board, cause a short, and poof, that's it. Search this forum, plenty of evidence for you.

Thank you Paralel.

The only other thing (ironically - to that comment) I'll point out is that there's stripped laminant near the pin 17 marker of the 9248XN chip (bottom right of the picture).  Anyone know what that trace is?

yeah you can clearly see all the trace rot at C9, from leaking cap goo... and you can see all the edge connector pins are all rotted up all along there.  Flux would make those soldered joints look a lot better by the way.

change all them as they are all bad.

then give a good wash...  a really good wash with soap and super hot water... get a tooth brush and scrub the crap out of that edge connector..  and all round the other various spots,  then give a hot water rinse, followed up with a air compressor blow dry off. make sure to blast out all the ports... PDS, Rom socket... under I/C's before you pop it back in to test.

Yeah I'm changing them all, essentially, at this point (until I run out of time today).  I don't see the trace rot at C9; though - is it possible you're talking about my garbage repair job?  (I'm trying to be self-deprecating, not defensive).

No dice after recapping and thorough washing and drying.  [sCSI Probe still shows a dot that indicates no data.]

I just reseated the caps again and still no change.  However, either after that or during my recap, I didn't properly connect one side of C9 to the pad, though it was probably conductive.  Uniserver, did you mean trace rot in the silver joints on the interface?  I just doused them with Scrubbing Bubbles and now I'm going to put the board in the dishwasher for a few minutes > distilled water > hair dryer > air dry.  I'm not optimistic.

I'm going to go pick up a Performa 560.  I assume that the mobo is swapabble in the same way a 550 is?

Yep! It should work perfectly, as it's identical to the 550, but with slightly different software options aimed at businesses.

c

Thanks.  That's what I figured.  The more interesting question is can I retrofit the 560's (550) chassis for the CC's motherboard?  That would go a long way toward showing it's a problem with the mobo.

[i figure it's bound to be something like this problem anyway:

But the CC uses a different chip (85c80) that also controls serial function; so I should also test the serial ports (though idk how much that narrows down which trace is at issue).  I found a pin labeling diagram (like listing what the pins do) but this isn't my background and I can't figure it out exactly; thus I can't figure out how to compare it with the 53c80's design/operation in the SE/30. - Well that and there's no standard 50-pin internal SCSI connector, so I have to figure out how that equates with the mobo interface.]

yup the CC mb works with the 5XX machines just fine.

Yes. The Performa 560 logic board and other hardware is identical to the 550. It came bundled with business software vs a home software bundle on the Performa 550. That ought to be an excellent way to rule out any CC chassis wiring issues for your SCSI problem. Personally, I'd want to keep the 560, perhaps just for the odd badging.

Oops, I typed this hours ago and it just sent.

No worries.  I appreciate the response.

Unsurprisingly, the 560 board boots from the startup disk in the CC chassis; the CC board does not detect the startup disk in the 560 chassis.

Are the ROM chips swappable?  And has anyone ever tried to trace the SCSI circuit to/through the interface pins?  It's clearly (I think) giving power through the rightmost four pins and the data is somewhere in the pins immediately beside those [those being the ones right behind/in front of the SCSI data cable].

You know, unless you *really* want a stock CC, you should just leave the 560 board in there and call it good, as you now have the equivalent of a Colour Classic II, which is a much more useful machine than a plain CC will ever be (the CC II has no 10MB RAM limit, a faster CPU, and full 32-bitness, which makes it considerably faster).

Anyway, swapping ROMs is irrelevant here, as I believe they both use the same ROM anyway, and whether it identifies itself as a CC or 550/560 depends on what the gestalt ID is. You *could try swapping them, but I doubt it'll do anything.

There's probably some rotted traces by the SCSI chip. The trick will be finding which ones and getting them repaired.

c

I did actually want to make it a stock CC.  But this CC came with a MacMicro (or something) 68030 FPU/32mhz accelerator so I basically already had the CCII speed.  The RAM thing is an issue, but I have so many macs at this point that I don't really need any one of them to be specific.  It's not like I'm going to throw out the 560 chassis so it doesn't really save space.  But I might wind up using the 560 board anyway.  Still, I want to repair the CC board.

So by means of reiterating: Has anyone actually diagrammed/traced/know of the official diagram of the SCSI circuit?  I found pinouts for 85c80, but I don't exactly understand what any of it means.  There's no obviously visible trace rot on the traces out of the 85c80.  Additionally, the external SCSI works, so I was trying to explicitly trace it to the internal circuit.  I'm not sure how the serial ports play into that.  [Although I will note if you look at the blurry picture of the back of the motherboard, the underside of the PDS has a random chip soldered between two of the pins on the underside of the board; I didn't notice that at first and I have no idea how that got there - unless a service technician screwed up back in the day - I got it from the original owner].

Can the CC board (if it didn't have a SCSI problem) use the CD drive in the 560's chassis?  If so that'd be a much easier way to test the serial ports etc.