The U60/220R Serial port console displays garbled text after the system board has been replaced to fix an unrelated problem. After power-on, the console will display several lines of garbled text, and may never complete POST. Serial console device and cable are known good, and STOP-N power-on reset does not resolve the problem.

Check the jumpers on the new system board and verify that they are set correctly. This problem has been observed when either the serial port mode or cpu speed jumpers are set incorrectly. While it might seem obvious that the serial port jumpers could be the cause, it is less obvious that incorrect cpu speed can cause the same symptom. For serial port jumpers J2604 and J2605, the factory default is jumper both 2-3 for RS-423, which should work for most serial console devices. Jumper J3001 should be jumpered 1-2 for 300 or 360 Mhz cpu's, and 2-3 for 450 Mhz cpu's. Refer to the Sun System Handbook for board locations of these and other jumpers.

When replacing a system board, it should be standard practice to check all the jumpers before installing it.

System board part numbers: 501-4450 & 501-5606

• thomas.quatrale@Sun.com