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.

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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