0F0004 error on 128k

[reallyrandy]

I'm reviving and restoring a 128k. When I boot from a floppy, I got a 0F0064 error after reading the floppy and giving a smily face. I assumed the floppy was bad so I tried a few more and got the same thing. Then I read that the 128 would only boot from System 3.2. So pulled out a system 1.1 disk from my 512k and it gave me a 0F0004 error and ejected after the smily face. I tried booting from my Floppy EMU but it wouldn't even recognize it in floppy or hard drive mode. I tried it plugged into the back and directly into the internal floppy port. Now I get a consistent 0F0004 error no matter what floppy I try.

Not sure what to try next to get it booted, any ideas?

 

[techknight]

RAM possibly. known for it. 

 

[Gorgonops]

Here's a list of Sad Mac error codes:

https://udcf.gla.ac.uk/~gwm1h/Error_Codes/Sad_Mac_Codes.html

According to that 0F0064 is "Couldnt Read System File into Memory". That could indicate issues with the floppy drive. 0F0004 is "Divide by Zero". That error can be triggered by trying to boot from an 800k floppy drive mechanism on a Mac equipped with the original 64k ROMs. (As you'd typically find in a 128k. It's caused by a bug in the ROM that causes it to freak out when it doesn't get "valid" RPM readings from an attached disk drive. The original 800k floppy mechanisms used by Apple didn't provide the right signal; later external drives, IE, the ones also compatible with the IIgs, and the Floppy Emu should fake it all right.) Assuming your Mac has the original 400k drive mechanism and you know it works I wonder if you might be having issues with the drive controller circuitry. Isn't there a resistor network/bornes filter that's a sore point of these machines? I wonder if a failure there could cause these problems.

 

[beachycove]

Some useful tips here: https://68kmla.org/forums/index.php?/topic/45311-128k-bad-ram-repair/

 

[Gorgonops]

Again, just to be clear, the error code doesn't indicate a RAM problem. While it's possible to imagine scenarios in which the RAM is broken in such a way that it passes the not-particularly-comprehensive POST test but is corrupting the OS load the error code is more suggestive of a disk subsystem issue.

 

[reallyrandy]

I have a 400k floppy from a 512k that needs restoration. I'll clean and re-lube that one first, then if it works I'll swap the floppy drives and see if I can boot with either one of them. I need to mess with my Floppy EMU and figure out how to boot with that. If I can figure that out, I can bypass the floppy and determine if it's a floppy problem or a logic board/RAM problem.