Lisa 2 / Macintosh XL floppy drive ejects disk immediately – troubleshooting help - HDD advice

[stefano.t]

Hi everyone,

I’m currently restoring a Lisa. So far We have repaired battery damage (corroded traces), rebuilt parts of the power supply (replacing transistors and capacitors), and fixed the video board. The system is now mostly working, but we are currently stuck on the floppy drive.

After cleaning the drive, pressing Apple+2 it now accepts the disk, but immediately ejects it. So I’m unable to verify whether the issue is with the drive itself, the I/O board or with the disks I prepared.

At the moment I’m unsure:

• whether the drive is faulty, or
• the I/O board works
• if I might have created the disks incorrectly

I was wondering if there are known diagnostic methods or tools to test the drive.
For example, are there any equivalents to something like a test ROM, Eprom, that could help verify if the hardware is working properly?

Also, my machine has ROM version 3A (so it should behave as a Macintosh XL, if I understand correctly). Does this mean it cannot read original Lisa disks and only supports the newer MacintoshXL-formatted ones? I’m not entirely sure about this and would appreciate confirmation.

At this point, I would also consider adding an HDD/SD-based solution instead of relying on floppy disks. Do you have any recommendations for compatible devices or products that work well with this system?

Any suggestions on how to properly test the floppy drive or create compatible disks would be greatly appreciated.

Thanks in advance!

 

[stefano.t]

Additionally, would it make sense to downgrade the ROM version in this case? If so, do you have any advice or best practices on how to safely perform the downgrade?

 

[stepleton]

Congratulations on your Lisa progress!

You're correct that boot ROM 3A means a Lisa set up to work only as a Macintosh. In particular, this ROM works with another ROM (the "video state ROM") that controls video timing and gives your Lisa square pixels instead of the slightly rectangular ones that were their original shape. Most of the diagnostic software out there requires rectangular pixels, so it will be better to revert this modification if you can in order to do further troubleshooting.

It's possible to get the appropriate ROM chips and program them yourself, though you may need a fancy ROM programmer for the video state ROM. I haven't attempted it. Alternatively, I would email the person who runs Vintage Micros and tell him that you want a ROM set for returning your Lisa to ROM H/rectangular pixels.

Once you have these ROMs, you just swap them into the CPU board.

I was wondering if there are known diagnostic methods or tools to test the drive.
For example, are there any equivalents to something like a test ROM, Eprom, that could help verify if the hardware is working properly?

There is no test ROM that I'm aware of. Most diagnostic utilities for Lisa are loaded from a floppy or a hard disk. There is a method for "side loading" BLU from a serial port (refer to the manual), but this is a utility for managing disks and not for diagnostics. It may still provide some clues about what the problem with your Lisa is.

I think BLU probably requires rectangular pixels, but you should check.

At this point, I would also consider adding an HDD/SD-based solution instead of relying on floppy disks. Do you have any recommendations for compatible devices or products that work well with this system?

This is a worthwhile approach. There are several options, but I recommend the ESProFile. It's cheap and it works well. There are probably online shops that sell ready-to-use units for a relatively low price.

Also, my machine has ROM version 3A (so it should behave as a Macintosh XL, if I understand correctly). Does this mean it cannot read original Lisa disks and only supports the newer MacintoshXL-formatted ones? I’m not entirely sure about this and would appreciate confirmation.

There is no real difference between 400K disks for screen-modded Lisas and original Lisas. Some Lisas had a modification that introduced an 800k double-sided drive, but these can still read 400k disks.

Any suggestions on how to properly test the floppy drive or create compatible disks would be greatly appreciated.

I have no specific testing suggestions myself. How are you making the disks now? When your Lisa ejects floppies you try to boot from, what does it show on the display?