Macintosh Plus - Sad Mac - 01FA00

[chrisdaun]

I don't know the history of this machine but it's really clean inside and out.
At boot the machine chimes but displays a Sad Mac error 01FA00.
Searching around and it seems like a Mac Plus should not throw an 01xxxx error.

I've tried swapping the ram chips around but got the same result.
When removing 2 simms from bank B I get a cycling pattern on the screen and no boot chime. Guessing because the Plus needs 1mb minimum to operate and removing 2 chips from bank B drops it to only 512k of ram?
Ram size resister looks correct for my 1mb setup.

Anyone run into this specific scenario before?

Thanks in advance!

 

[dochilli]

A 01 error means that there is a ROM error. Plus ROMs are sometimes defect.
You can burn new ROMs with an eprom burner.

Create Macintosh Plus ROMs

Create Macintosh Plus ROMs: This Instructable will guide you through the process of "ripping" EPROM images from from your Macintosh Plus ROM chips and (or) "burning" the images to new chips. The process will basically be performed twice to create both "hi" and "lo" ROM chips f…

www.instructables.com

 

[chrisdaun]

Ah thanks. Maybe I’ll try dumping my roms and comparing them to the images available online

 

[dochilli]

There are different versions of ROMs. You have to look, which version you have.
And the plus ROMs are split into two files (high and low).
Here you can find two windows programs to split and compare roms.

Software for ROMs

Perhaps someone is interested in two programs for ROMs that I developed. SplitRom can be used to split a ROM into high and low ROM. CompareROM compares two ROM-Files. When they are identical then there will be shown zero differences. I use the programs in Windows 7. They were programmed in...

68kmla.org

 

[daanvdl]

I recently built a small macOS app that might be useful to anyone working with classic Macintosh hardware or custom ROM replacements:

ROMSplitter​

A macOS utility that splits a single .rom file into two files: LOW and HIGH – exactly how many vintage systems (including early Macs) expect them when burned to physical ICs.

Why split ROMs?​

Many classic computers like the Macintosh 128K/512K(e) and Plus use two 8-bit ROM chips working together to serve a 16-bit data bus.
These chips are interleaved:

• The LOW ROM contains the even-numbered bytes (0, 2, 4…)
• The HIGH ROM contains the odd-numbered bytes (1, 3, 5…)

This app takes a single linear .rom file (from a ROM dump) and splits it correctly so you can burn the two outputs to, say, a pair of 27C512 EPROMs.
Outputs: <FILE>.low.ROM and <FILE>.HIGH.rom in the same directory

Hardware tip​

Make sure to use two EPROMs with matching access times. Mixing chips can cause boot issues or instability in some systems.