Brother International HL-2400C Service Manual - Page 129

2.4 DRAM Test Mode This mode tests the memory and optional SIMMs installed on the main (video controller) PCB. 1) To start the test program: While holding down the w button, turn on the power. "DRAM CHECK START" will be displayed. Press the Continue button to start the DRAM check. 2) The LCD will display "START DRAM TEST", and the Data LED blinks. 3) On satisfactory completion of all the RAM tests, the LCD will display: "DRAM OK!!", and the Alarm LED is on. 4) If any DRAM error has occurred, the LCD will display a fail message as follows; RAM Address WRITE data READ data 5) Enter the hidden menu mode as follows to confirm the current memory map; i) Press the Form Feed, Mode and Continue buttons at the same time in the offline status. ii) The LCD will display "HIDDEN PANEL" iii) Select the "DRAM ADDRESS" menu using the scroll buttons. iv) Whenever the Set button is pressed, the LCD will display the DRAM error address on the main PCB, Slot 1, Slot 2, and Slot 3 in turn. 6) If a SIMM DRAM has an error, replace the SIMM corresponding to the above memory map information. If the DRAM on the main PCB has an error, replace referring to the table below; Lower order address (where an error occurs) 0, 4, 8, C 1, 5, 9, D 2, 6, A, E 3, 7, B, F DRAM chip to be replaced *A *B #3 #5 #9 #16 #4 #7 #14 #20 *A: If the upper digit of the data is wrong. *B: If the lower digit of the data is wrong. Note: • There may be a case where the above sequence does not work correctly due to complete RAM failure, or in faulty assembly such as a solder bridge or ineffective soldering etc. • "PRINT CHECK" may be displayed when exiting from the Test mode. It will disappear in 20 or 30 seconds, displaying "READY" on the LCD. It is not a fault. V-8