My trusty Mac LC no longer boots from the HD

Addendum

If you can find someone with a suitable older (approx. 1991 to 1997) Macintosh computer, here is a list of older Apple software:

http://www.info.apple.com/support/oldersoftwarelist.html

A plain Network Access Disk 7.5 can be used as a general startup disk (and, as mentioned earlier, it can be the base for utility disk modifications). It can also be used to access files on another Mac via a simple LocalTalk network (a normal MiniDIN-8M to MiniDIN-8M printer cable between the serial printer ports):

http://download.info.apple.com/Apple_Support_Area/Apple_Software_Updates/English -North_American/Macintosh/Utilities/Network_Access_Disk_7.5.sea.bin

Disk Copy 4.2 (the Make A Copy button) can be used to create a properly sector-copied floppy from a downloaded NAD 7.5 disk image:

http://download.info.apple.com/Apple_Support_Area/Apple_Software_Updates/English -North_American/Macintosh/Utilities/Disk_Copy/Disk_Copy_4.2.sea.bin

Apple HD SC Setup 7.3.5 can be found here:

http://download.info.apple.com/Apple_Support_Area/Apple_Software_Updates/English -North_American/Macintosh/Utilities/Apple_HD_SC_Setup_7.3.5.sea.bin

For information about other programs, you may want to try an Internet search for something like 'format SCSI Mac'.

Please note the volume size limits:

http://support.apple.com/kb/TA2711

Mt. Everything can be used to detect a drive on the SCSI bus:

http://www.overnet.de/hhp/mte/

SCSI Probe was a similar utility:

http://support.apple.com/kb/TA48033

BTW, with an appropriate cable/adapter, many PowerBook computers can act as an external hard drive in SCSI disk mode (see, for example, page 31 in the PB 500 series manual below).

http://manuals.info.apple.com/MANUALS/0/MA640/en_US/PowerBook_500series_UserGuid e.pdf

Jan

Hi Len,

>but the 'new' logic board couldn't find either of them.

The first requirement for a hard disk to become visible on the Desktop is of course that it has been properly formatted/initialised (with an appropriate driver installed). The second would be that the SCSI bus/chain is OK. Otherwise, the hard disk will not mount.

When you say that no SCSI drive could be found, was that a result of a drive search in an old HD SC Setup program on a Disk Tools floppy? HD SC Setup may have difficulties detecting drives; third-party drives (or Apple drives with an altered formatting) cannot be expected to appear at all. It is really essential to have access to alternative tools.

Is there an Apple User Group in your area? If so, someone there could perhaps help you locate a suitable older Macintosh computer.

http://www.apple.com/usergroups/

A problem with the power supply under specific load conditions cannot be ruled out, but it all seems to work well with the floppy drive.

If necessary, do not hesitate to post back later with questions about floppy modifications etc.

I wish you a Merry Christmas!

Jan

Hi stevena1,

>Apple never published schematic diagrams for any product.

Just to clarify, I was referring to 'component level circuit diagrams' in this very case.

Earlier, developer notes (which often contained block diagrams) for old hardware products could be found here:

http://developer.apple.com/documentation/Hardware/Hardware2.html

Unfortunately, that address now returns an error message. However, one should perhaps not rule out that the page exists in an Internet archive somewhere. Generally speaking, it has become increasingly difficult to locate older Knowledge Base articles, etc. Sometimes the material is still available at an Apple web site, but you may have to use Google to find it.

Jan

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

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.

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

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

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

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.

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.

Hello Len,

Thank you for the report. Sorry to hear that it was not possible to get the hard drive to be properly recognised. Could of course be almost anything else, like bad semiconductors, in addition to the capacitors. Good luck with the replacement board!

Jan