• Hello, Guest! Welcome back, and be sure to check out this post for more info about the recent service interruption and migration.

Color Classic Internal SCSI

raoulduke

Well-known member
I got a Color Classic today that wouldn't power on.  I fixed the mother board; then I got a reddish hue issue that went away with adjusting the internal controls.

Throughout, the internal HD didn't seem to work.  I took it out and put an 80mb Maxtor that I knew worked in its place and got a striction sound upon startup.  I tested both in an enclosure with the CC and both worked fine.  Disk First Aid and Apple HD SC (unpatched) don't register the drive at all, though I can hear it power up at startup.  SCSI Probe (4.3) might be recognizing something at ID0; it shows a black dot that it says means "No Data".  So the two issues are (on the stock IBM 80mb drive) some data problem, and on the Maxtor something potentially more serious.  Any thoughts would be appreciated.

[i just found this https://68kmla.org/forums/index.php?/topic/25863-color-classic-scsi-issues/ , though not really similar, and a passive pass-through terminator has no effect.]

My hands are cut up already and I don't relish replacing the internal cables.  I feel like that will take days (or at least a full actual day) and may not be the issue.  Any thoughts?

 
Last edited by a moderator:

uniserver

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

 

raoulduke

Well-known member
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).

 
Last edited by a moderator:

raoulduke

Well-known member
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.
 

Bunsen

Admin-Witchfinder-General
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.

 

raoulduke

Well-known member
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.

 
Last edited by a moderator:

CC_333

Well-known member
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

 

CC_333

Well-known member
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.

 

raoulduke

Well-known member
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?

 

raoulduke

Well-known member
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.)

 
Last edited by a moderator:

uniserver

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

Thanks.

 

uniserver

Well-known member
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.

 

raoulduke

Well-known member
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.

 
Last edited by a moderator:

Paralel

Well-known member
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.

 
Last edited by a moderator:

raoulduke

Well-known member
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?

 

uniserver

Well-known member
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.

 
Top