General Category > Lisa Troubleshooting and Repair
Will the Lisa return an IO error without the "Lite" Interface Card
friedboard:
Thank you again for the detailed analysis! I checked my motherboard and it is indeed a 620-0108-E which only has an external parallel port.
I seem to have a stock lite adapter with no modifications at all
The weird part is that my floppy drive was working just fine with floppyemu before the esprofile incident. I was able to load up Lisa 2 diagnostics, macworks 2 and boot to macos just fine.
I plan to replace the 8T97 first to see if that will make a difference as it seem to hang with error 23 after the initial 57 on boot. (only with floppy emu)
sigma7:
--- Quote from: friedboard on August 15, 2025, 11:37:51 pm ---The weird part is that my floppy drive was working just fine with floppyemu
--- End quote ---
I have a vague recollection of someone mentioning this phenomenon before, so there are clearly some holes in my logic/understanding/memory.
I presume the FloppyEMU works in that case because it does not need the motor speed signal. AFAIK, it can determine the virtual speed based on the track number, and I suppose it doesn't need to vary anything at all in that regard, since the change in RPM is only to make the flux change density on the magnetic media more consistent, so the digital rate remains the same regardless.
Now I wonder if there are further consequences, such as:
* is it the case or my imagination (or hallucination -- I promise that I'm not AI) that the superdrive doesn't use the motor speed signal? If so, will it work in this configuration even though 400K and 800K drives don't? (Don't try it if you don't know... maybe the wiring isn't compatible in some way)
* does the same effect mean that a 1/5 I/O Board will work with a FloppyEMU and 2/10 motherboard and chassis cabling?
friedboard:
What is strange is that it came from eBay this way and I assume the machine must have been in a working state before and not modified after. It has a "Lisa is now Macintosh XL" sticker in front, H/88 ROM and a switch to toggle screen height (I assume to work with MacOS and Lisa OS)
Even though the original drive is stuck it was plugged into the lite adapter and the red light works
friedboard:
Here is a picture of the IO board
friedboard:
Part of the motherboard
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