Sad Mac 0F0004

[nextse7en]

Hi folks, I'm having an issue with one of the 128ks I'm restoring.

When attempting to boot a known good 400k system disk in a known good 400k drive, I get a sad Mac 0F0004 error. Swapping the logic board for another 128k board relives the symptom, while the disk, drive, and analog board remain the same.

Any ideas on what's going on with this logic board, and what I can do to fix it?

The resources I've got at my disposal seem to conflict in this, one says its an 800k drive problem with the 128k rom, one says its a divide by 0 trap, and one says its a low voltage issue.

Halp!

 

[waynestewart]

Let's see if I understand correctly.

You've tried two different motherboards in the same system and had the same error code?

You know you have a good 400k drive.

Have you checked the voltage going into the motherboard?

 

[uniserver]

bad ram chip

 

[nextse7en]

Let's see if I understand correctly.You've tried two different motherboards in the same system and had the same error code?

Err, no.

Swapping the logic board for another 128k board relieves the symptom

Uniserver, is there a way to test the chips individually?

 

[uniserver]

well you could do it the poor mans way, with a multimeter and find the one that is different then the rest but I am totally talking out of my rear on this... I have seen threads on here that talk about exactly what you are doing. bad ram chips on the 128k main board.

 

[trag]

I think that the numeric portion of the error code is an indicator of which memory chip failed. I would need to check the Dead Mac Scrolls or some such though. Or an internet search might turn it up.

 

[mcdermd]

For Sad Mac code 0F0004, The Dead Mac Scrolls says:

Symptoms: On startup, the compuiter bongs, but then you get a sad Mac with error code 0F0004.
Typical history: The problem occurred right after upgrade or service work on a 128K or 512K Mac with 64K ROMs.

Probable diagnosis: The analog board is out of adjustment.

Solution: Turn variable resistor R56 (labeled Voltage) fully counterclockwise. Restart and adjust R56 for 5.0V DC as measured from pin 6 of the power/video cable to chassis ground.

Sad Mac code ##0001 is RAM chip F5

Sad Mac code ##0002 is RAM chip F6

Sad Mac code ##0004 is RAM chip F7

Sad Mac code ##0008 is RAM chip F8

Sad Mac code ##0010 is RAM chip F9

Sad Mac code ##0020 is RAM chip F10

Sad Mac code ##0040 is RAM chip F11

Sad Mac code ##0080 is RAM chip F12

Sad Mac code ##0100 is RAM chip G5

Sad Mac code ##0200 is RAM chip G6

Sad Mac code ##0400 is RAM chip G7

Sad Mac code ##0800 is RAM chip G8

Sad Mac code ##1000 is RAM chip G9

Sad Mac code ##2000 is RAM chip G10

Sad Mac code ##4000 is RAM chip G11

Sad Mac code ##8000 is RAM chip G12

 

[bbraun]

Thanks mcdermd! This plus http://support.apple.com/kb/TA46376 helped me fix my 128k.