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My trusty Mac LC no longer boots from the HD

I purchased a new Mac LC many years ago and it has served me well until recently when it would no longer boot from the hard drive. When I boot from a Disk Tools floppy, I get some limited success but do not ever hear the HD spin up. The startup chime also does not sound. When used as the boot disk and trying to use the installer option, the program can't find a SCSI drive, only the floppy drive. The 5V & 12V to the HD are right on and a new PRAM battery is installed. I can load and run programs using the floppy drive but that requires a lot of disk swapping. I tried substuting a tested Apple LC HD with the same results and now I suspect the problem is not the HD but is somewhere else. Any help would be gratefully appreciated. Thanks!

iOS 6.0.2

Posted on Nov 29, 2013 7:09 PM

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29 replies

Nov 30, 2013 1:07 AM in response to len-35

Since the LC starts up OK from a floppy, the battery is new, and another (working) hard drive has been tested without success, one should perhaps suspect a problem on the logic board. It may be wise to check all connectors first. The board can then be inspected with a magnifying glass. Is the printed circuit board itself in order? Look for obviously damaged, discoloured, bulging or leaking components, especially electrolytic capacitors.


Jan

Nov 30, 2013 1:20 AM in response to len-35

Does the substitute hard drive have its "termination enable" (TE) jumper installed? Although it seems unlikely, did you change the SCSI ribbon cable, just in case it has developed a problem? If you had an external SCSI enclosure to accommodate the hard drive, I'd suggest installing it in it and connecting to the external DB-25 SCSI port. The original Mac LC shipped with a 40 or 80 GB hard drive, but you can use a larger capacity drive than either of those. You've indicated checking the voltages on the hard drive's molex power plug, but did you check the voltages on the power supply's main connector at the motherboard, to determine if the problem is there.

Nov 30, 2013 1:44 PM in response to Jeff

Thanks to Jan & Jeff for their quick response to my question. Here is some additional background information which may give you both some more ideas.


The original 40 MB HD was replaced with a 120 MB HD along with an increase in RAM to 4 MB sometime in the first year after I bought the LC. The 40 MB HD was installed in an APS (?) external SCSI box with its own power supply. OS 7 was just becoming available and Apple gave me a set of disks even though OS 6.x was in the computer so I put OS 7 on the external (40 MB) HD. Everything worked great for 20 years although there were periods of intermittent use when I used other computers for work, Internet, and e-mail. I powered up the external HD infrequently but it worked fine the last time I tried it some months back.


Then when I fired the LC up 6 or 7 weeks ago, it would not boot unless I turned the power switch on & off 2 or 3 times in succession then everything functioned normally. Then it would not boot at all even from the external HD.


Now, to address some of your comments and observations:

All connectors, plugs, SIMMs, and socketed RAM devices were removed, examined and replaced. All electrolytic caps showed no signs of leakage or swelling and the PWB looked in its original condition.

The +5, -5 and +12 voltages measured at the power supply connector were within 1%. When I originally thought I had a HD problem, I opened up the 120 MB HD and when trying to boot, the platter would give a slight twitch with no tendency to spin. A friend of a friend (a MAC serviceman) brought a couple of vintage drives SCSI over to try with similar results. The Apple HD I purchased was tested and guaranteed, although wiped clean. It has since been returned. As I said in my original question, the Installer on the floppy could not find a SCSI drive. In all of my efforts I could never get any of the hard drives to spin up.


Although I have a MacMini (OS 10.6.8), I still used the LC because for drawing schematics and floor plans, printing labels, etc., simple is better for me. Is there any hope that I can get my LC working again?


Many thanks for your help and suggestions. len-35

Nov 30, 2013 2:52 PM in response to len-35

Usually, when there is a change during storage, it is related to either corrosion (connectors) or bad batteries or electrolytic capacitors.


You have checked the connectors, and the battery is new (if not already done, it is not a bad idea to verify the voltage). I suppose that you have tried a PRAM reset as well.


Old electrolytic capacitors can often create problems. There is a risk of leakage or that the electrolyte dries out. Can-type capacitors may bulge or leak. A crack or discolouration may be a sign of a faulty SMD capacitor. Unfortunately, it is not always easy to tell whether an electrolytic capacitor mounted to a circuit board is bad or not.


In this case, it appears as if something has happened to the SCSI (hard drive) control circuits on the logic board.


However, it is a bit puzzling that a startup sound cannot be heard (during an apparently otherwise successful startup from a floppy). Is the speaker and its cable OK?


Also, when starting from a floppy, do all the regular icons and messages appear?


I am sure that you are aware of that Apple HD SC Setup on a Disk Tools floppy (normally) is limited to the handling of Apple hard drives (that have not been reformatted by a third-party utility). All other SCSI hard drives require a third-party formatting utility (or, in some cases, an appropriate version of Apple's Drive Setup). Apart from the formatting utilities, Mt. Everything and/or SCSI Probe may be useful when trying to detect hard drives.


Jan

Nov 30, 2013 7:08 PM in response to Jan Hedlund

Hi Jan.

To answer your questions, when booting from the floppy, everything works normally except the startup chime; the smiling Mac, Welcome message, Floppy icon, etc.

(The sound volume has been decreasing steadily for some time so I’ll check the speaker with an audio signal instead of the ohmmeter check done previously).

BTW, can you describe the location on the PWB containing the SCSI control circuits? I think I’ll start working there first.

Here’s my present game plan:

I plan to selectively replace most if not all of the electrolytic caps.

I’m going to reinstalling the original 40 Mb Apple HD.

This may take some time to collect all of the caps and install them.

I’ll post a status message as the project progresses.

Thanks again for your input .

Len

Dec 1, 2013 6:01 AM in response to len-35

Hi Len,


First of all, regarding the sound, you could perhaps check whether there is a problem with contact oxidation in the external speaker/headphone jack (leading to a reduced/cut signal to the internal speaker).


I checked inside an LC III (which should be similar in many respects to a plain LC). Near the external DB-25F SCSI port one can see a large chip (containing an 85C80 marking) which would be responsible for SCSI (and serial). You may possibly want to begin looking for any obvious faults in this area, and all the way to the internal hard drive connector. I guess that the LC has both square SMD and can-type electrolytic capacitors (like the LC III; all marked Cn on the board).


Good luck!


Jan

Dec 1, 2013 12:25 PM in response to Jan Hedlund

Hi Jan,

Today I field stripped the LC completely and examined the PWB under the stereo microscope and found that most of the electrolytics showed signs of leakage. Ordered an assortment of caps on eBay and should have them in a couple of weeks (made in Japan; shipped from China!). Are you aware of a good way of removing the old caps? I’ve been a techie for most of my life but the small SMD caps may be a real challenge. Also checked the speaker and it’s good; the low output may be the result of bad caps too.

Hope the outcome is worth the effort!

Len

Dec 1, 2013 2:20 PM in response to len-35

Hi again,


I guess that you have access to both a desoldering pump and desoldering braids, and a good soldering station. In order to study various techniques in advance, you may want to have a look at the information available on the Internet (try a search for something like removing capacitors). SMD can be difficult to handle, but one has to be careful with capacitors with leads as well in order to avoid damage to conductors on the board.


Yes, it is probably entirely possible that bad capacitors could be responsible even for the sound problem.


Jan

Dec 2, 2013 1:31 AM in response to len-35

If anyone is interested (who hasn't owned/worked on an LC), this web site has a good collection of photos of many vintage Macs, including the original LC. There are multiple high-resolution photos of the interior/motherboard. For comparison purposes, the LC III that Jan referenced is also listed. I have an LC and an LC III. The LC III was a big improvement (at the time) over the LC, for the same reasons mentioned on the LC III page. Not too many years ago, one could find a number of listings for LCs - complete or parts - at ebay. Scarcity or lack of interest has caused an obvious decline in LC-related auctions. Thrift stores, yard sales, and Mac User groups may be the only options for finding units or parts.

Dec 14, 2013 4:12 PM in response to len-35

Are you going to try and fix it ? I have just read the News that the we consumers are to blame for dumping e waste every year new devices are made and the life is shorter ,we are dumping them at a ever increasing rate on poor countries and they are made of so many parts and materials.


I would like to see Apple doing a lot more to help people like us that try to fix old devices.


I also pick up old Macs and buy them to re use ,but the parts and tools and way to fix them is diffficult ,they are becoming more difficult to fix because the parts and materials are of different life and on a part like motherboard we do not know which is gone bad so we have to struggle to find it.


The biggest problem for me is I do not have enough knowledge of electronics and know how and just learn by doing and undoing, internet ,Youtube and going to Electrical part shops and Second Hand shops.


There is a growing awareness that rare metals and materials from nature are getting used up that we will have to start stripping down old devices ,my parents said the Sheffield Council were asking people to denote their Iron Railings and Garden Gates to help the war effort to make tanks and weapons .so keep your broken things and in the mean while try to think of ways to re use it.


I always keep many things that come from packaging I pick up broken things off the street and always toying with them to think of new ways to use them for Art and Usable Art or Modding old and new things assembled together.


Apple and many other makers made good divices ,but they are a business and unfortunately new and more complex devices are made and old ones become obsolite Apple should do more to help those who want to re use old devies.

Dec 14, 2013 7:53 PM in response to Jeff

Hi Jan


The electrolytic cap assortment I had ordered (130 pcs, $9.75, eBay/China) came today. I had already removed the fifteen old caps from the PWB so I headed down to my shop to install the new caps. The job went fairly smoothly and after verifying all the correct values, polarities and solder connections, I reassembled my trusty Mac LC and applied power.


Sad to say, the new caps did nothing to restore the HD non-boot condition. I could still boot from a floppy disk but I never could get the HD to spin up. As before, there was no startup chime, the Installer on the floppy could not find a SCSI drive but I did get a happy Mac. I think I may have a defective device and if so, it may be time to retire the LC.


PS - This evening I made an offer on eBay for an LC logic board so I may still have a chance to get my LC back. I’ll probably have to change all the electrolytic caps though.


Len

Dec 19, 2013 11:20 AM in response to Rajapintaja

Macs are expensive (hate to say!)


At least a Mac mini is under $700. The LC was the mini of the 1990 standard, and that was $3,700 MSRP (w/out a monitor!)


However very Vintage Macs are perfect to use to play the classic games (like Monopoly, Spellbound, Number Munchers, oh and the Mac edition of the Oregon Trail!)


Old tech is still used in many closets, depsite what your hear in the media towards iPads and cloud services.


My DSLR photos are now stored on a Mac OS Tiger on G3 B&W tower firewalled and secure as much as possible. With my 100GB+ photo collection, its heluvla lot easier to store them on a Mac than a Windows Server - Macs are built to run and run and run for days and months without restarts! Try saying that about MSFT.


I am still using the 2nd gen MacBook (bought in '07) and its been through a lot, but I have for the most part taken good care of it, and the last couple of years, I felt I got every pennies worth out of this thing!


Back to the subject, hope you get your LC fixed. That's one of the best compact desktop models in Apple's history IMO!

Dec 21, 2013 6:17 PM in response to Jan Hedlund

Hi Jan


The 'new' board came today and was installed. With a floppy boot disk, got a start-up chime, smiley Mac and could run a program with lots of disk swapping but no boot from the HD. Still couldn't find a SCSI drive. This is the same as my original board with the replaced caps. Either the 'new' board has a problem (but got the start-up chime, etc.), the HDs I tried are all bad, or ...


The one thing I'd like to try is to get my hands on a good HD with OS 6 on it. When I began this saga I did purchase a SCSI drive that had "wiped" clean but that was before I changed the caps and I never got it to spin up anyway. I'd be willing to invest about $30 in another drive from the same outfit but I'm not sure what you have to do to get it working with the LC assuming the 'new' board turns out to be good.


I'm about ready to call it quits. Got any ideas?


Len

Dec 21, 2013 6:32 PM in response to stevena1

I'm using a MacMini as my primary computer and you're right when you say that "obsolete" computers are still useful for many applications. The one reason I'd like to get my LC running again is the programs on it are mostly devoid of the bells & whistles in the latest versions of software (that I don't use or need).

Regards, Len

My trusty Mac LC no longer boots from the HD

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