Troubleshooting dead CD on Rev. A

5 replies [Last post]
doug-doug the mighty's picture
Joined: Apr 14 2004
Posts: 1355

Alright, there is enough knowledgeable folks here to help me figure this out, and I thank in advance anyone with an untried ideal.

The machine:
Rev. A iMac - 233MHz - 512M/6M - 120G/24x - added connector for floppy (only works when booted at 8.5 or lower)

The full story:
My HD is a 120G with three partitions. The boot partition (7G) had X.2.8 and a 9.2.2 OS. Everything worked well. On another partition, is a few DiskCopy images of the 7G partition with varying stages of OS (8.1, 8.5, 9.1, and X(base), X.2.8, ... ). I kept these because I would periodically need a test bed to let me hack around with the OS (via ResEdit). During one episode, I dropped an image of OS X back onto my HD. I forgot to boot back onto an OS X CD and run Disk Repair to fix the permissions and attempted to boot directly back into OS X.2.x. At this time many things were bad - big understatement, huh?

I was able to take my original 4.3G and reinstall it. This drive had a clean install of OS X.1 and 9.2.2. As I saw life come back to my precious, I noted that the CD was dead. On some occasions, the physical device was viewable from ASP, sometimes not. In every case, the tray would open when the button was pushed (it is getting power) and would spin the disk a few times when one was inserted (recognition that something might be there - maybe?), but no volume would ever be mounted.

I have verified all physical connections, left the machine unplugged for a few days, reset the CUDA, reset the nv-ram, reset the pr-ram, and tried every bootable (Apple mfrd) CD I have. I have since upgraded my CD to a MCE CD RW. The device is not being recognized either. I am fairly certain that the physical drives (original and replacement) are in good working order. I believe that something has been corrupted that resides on the mother board or somewhere off of the HD. Since I placed in a good HD with a known working config for this very machine and have swapped (CD) drives with no results, I am led to believe th problem is something on a board.

I beg any of you for some insight.

Other assets:
I have a working floppy drive and a boot disk for OS 7. I have not yet tried to boot the iMac from this drive as I do not have the cable plugged in at the moment. If I boot into firmware, how do I tell it to find this drive (mac-boot ?)

Thanks!

-- doug-doug the (not so) mighty (at this particular moment).

__________________

--DDTM ('Fritter Critter' since Apr 26 2004 - 18:16)

'If it ain't broke, take it apart anyways. If you can't take it apart, break it so that you can fix it.'

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
dankephoto's picture
Offline
Joined: Dec 20 2003
Posts: 1900
parts for swapping . . .

available? I'm guessing though that this is your only iMac on hand right now. Ideally one would borrow stuff from another known-good unit . . .

How about the CD cable, any possibility it got damaged during all that mucking about? The intermittant ASP visibility supports this possibility, typical of problem cabling.

Can you run the CD drives in another machine to test if they really do work? Since these are standard laptop slim drives you can use a slim-to-IDC40 adapter to test in a desktop 'puter. Or use a laptop w/optical that uses standard slim drives (eg: PBs 1400 w/12x CD, or Lombard/Pismo.) Heck, if you have such a laptop, swipe its known-good optical drive and try it in the iMac. Or double-heck, with the above adapter, you could test the CD drive on the iMac's HD bus.

BTW, it's still a 233?!?!? Laughing out loud It's trivial to speedbump those suckers to 266 or 300. Both my 233 rev Bs now run quite comfortably at 300mHz.

Dan K

__________________

|| web page gone - curse you Comcast! | Applish goodies servers offline, sorry! |
» email macdan at comcast.net

Eudimorphodon's picture
Offline
Joined: Dec 21 2003
Posts: 1204
Open Firmware fun

Here's a page that has all sorts of useful tidbits regarding Mac firmware:

http://www.kernelthread.com/mac/osx/arch_boot.html

Look in particular at the bit about looking at your device tree. It might be educational to see if the device pointed to by the "cd" alias is actually present, for instance.

It may be that your secondary IDE bus is munged, of course, although it's hard to imagine how software issues like you've described having could do that.

--Peace

doug-doug the mighty's picture
Joined: Apr 14 2004
Posts: 1355
Yes, it is my only iMac. The

Yes, it is my only iMac. The cable appears to be okay, visually. I will improvise a means of verifying this with a continuity tester later tonight. My only other machines on hand are a 300MHz iBook and my wife's 15" flat panel (an 800MHz w/ SuperDrive). I cvalue my life, so the wife's machine is out-of-bounds and the iBook is my only 'unspoiled' resource.

I do have plans to clock-chip the processor, but that is a 'will do later' item. I have tossed around the idea of doing that or forking out for the Sonnet upgrade with firewire on the card. But first things first...

The new CD RW does seem to confirm your suggestion and my suspiscion, I will do more than visually inspect the cable.

-- doug-doug

__________________

--DDTM ('Fritter Critter' since Apr 26 2004 - 18:16)

'If it ain't broke, take it apart anyways. If you can't take it apart, break it so that you can fix it.'

doug-doug the mighty's picture
Joined: Apr 14 2004
Posts: 1355
good stuff...

Thanks!

I have been fiddling around (just looking that is) at this stuff for a few hours trying to figure out what it is telling me. I will explore some of the other links (FCode and stuff) of the link you gave. From what I can see right now, I am unable to get the expected results from the 'dir hd:\' command. I see the listings for of the hd and cd under 'devalias', but need a little more time to figure out what I am really looking at. I recognize the hex characters will be of some value at this time. It is not that dissimilar in concept from trying to decipher the hex dump from ine's registers after a mainframe application has abended and all your stuff gets flushed into some JES2 output. I digress, but the point is think something good is here.

Of immediate notice is the fact that when I do a 'dir cd:\', I get the same results as when I do a 'dir hd:\' - I can here the cd spin up and continue spinning. It stops after a minute or two and an OPEN failure of some sort appears. At least it is consistent from 'cd' to 'hd'.

-- doug-doug

__________________

--DDTM ('Fritter Critter' since Apr 26 2004 - 18:16)

'If it ain't broke, take it apart anyways. If you can't take it apart, break it so that you can fix it.'

doug-doug the mighty's picture
Joined: Apr 14 2004
Posts: 1355
EUREKA!!!

Well, I FINALLY got a chance to pull out my continuity tester...

I took the mother board out and tested the continuity of the CD cable whilst connected to the board and CD adapter. I figured that this would ensure i had a bood connection from board to device rather than just that the cable itself was okay. Everything checked out okay, much to my chagrin. So I made sure everything was nice and tight and put it all back. Whe I tried to boot up, I will be damned if it did not just totally come up off a 9.2 CD.

Seems that some where a connection must have been just a hair off. Strange, considering how many times I had pulled it out to check connections and other things.

Now I have a working 24x internal CD RW in my baby Bondi!!! Don't know if it will record, but it will at least read!! And MCE sent a slot loading device rather than a tray loading device. This makes my machine a slot-loading 233!

Thanks for all the help and ideas along the way guys!!

--Doug-Doug The Mighty (feeling mighty again).

__________________

--DDTM ('Fritter Critter' since Apr 26 2004 - 18:16)

'If it ain't broke, take it apart anyways. If you can't take it apart, break it so that you can fix it.'