macintosh classic hard drive not showing up.

>I've put a little connector between A0 but that din't make a diffrence and A1 also din't do anything.

As I indicated above, the chosen SCSI ID is not really of importance, if between 0 and 6, providing that no external SCSI device is connected. So you should (typically) have no connectors/jumpers/clips at A0, A1 and A2 (resulting in an ID 0 for a single internal hard drive).

The only setting that could create a conflict (and error messages) would be ID 7 for the hard drive. ID 7 is reserved for the computer.

The hard drive is supposed to be terminated when in a Macintosh Classic. Some drives have a TE jumper position in order to enable termination. Your drive appears to use another method; termination is enabled by plugging in resistor packs. So, the resistor packs must be on the hard drive's controller board in this very case.

>could it be that i received a failed hard drive?

Yes, (if termination is OK, and there are no SCSI ID conflicts) one would at least suspect that, since the computer seems to run well without the hard drive. You should ask the seller whether the drive had been tested, in which computer, and how it had been formatted.

You may want to read more about SCSI. For example, try a web search for something like "Mac SCSI termination".

Addendum

It will probably not make any difference at all, but it does not hurt to try it anyway. Under certain circumstances can bad SCSI hard disk drive drivers affect the system startup. Insert a bootable floppy, start the computer, immediately press and hold the four keys Command(Apple) + Option + Shift + Delete(Backspace). Any change?

If a hard drive prevents the computer from starting up, either from ROM or from a floppy, one would suspect that something is wrong with that drive. When you said that you disconnected it, did you mean completely (the hard drive's power and SCSI connectors) or just the hard drive's power connector?

Also, how did the computer act when the old hard drive was in place? Was it then possible to boot from ROM and/or floppy?

At this point, the behaviour of the new hard drive appears to be suspicious, but we do not know for sure. It is very difficult to diagnose a problem with access to merely a semi-working computer.

The exact new hard drive model name/number is still not quite clear. "540S" can be seen on a label, but there may be additional information of interest on the other side of the drive. The jumper situation is also a bit unclear.

Have you tested the new drive without the resistor packs (if in fact removable), with or without a terminator connected to the external SCSI port? However, please note that there is a risk that the computer and/or the hard drive may become damaged because of improper SCSI termination.

You should really try to locate another approx. 1991-1997 Macintosh computer (with a built-in floppy drive, and preferably Ethernet and a CD-ROM drive), that could be used to create special bootable disk tools floppies (for example, with Lido 7.56, and Mt. Everything or SCSIProbe). An external SCSI enclosure (for a hard drive or a CD-ROM drive) could be useful in order to connect both hard drives (the old and the new) to the SCSI port of the other Mac for tests. Also, a SCSI Zip 100 drive would allow some comparative tests at the Macintosh Classic.

Also, it may be wise not to rule out a possible issue involving circuits (SCSI?) in the Macintosh Classic. Has the logic board battery (3.6 V) voltage been checked? Under certain circumstances, with some computer models, a bad battery can cause unexpected problems. Resetting the PRAM (holding down the four keys Command+Option+P+R at startup) is a procedure that often does not lead to anything, but sometimes it helps. There could be faulty components on the boards (one may want to use a magnifying glass or a microscope in an attempt to discover various cracked/discoloured electronic components, leaking electrolytic capacitors and bad solder joints).

Hi,

Glad to hear that it is working now.

Jan