Undetermined problemsUse the information in this section if the diagnostic tests did not identify the failure,the devices list is incorrect, or the system is inoperative.Damaged data in CMOS memory or damaged BIOS code can cause undeterminedproblems. To reset the CMOS data, use the password override switch to overridethe power-on password and clear the CMOS memory; see “Erasing a lost orforgotten password (clearing CMOS memory)” on page 99. If you suspect that theBIOS code is damaged, see “Recovering the BIOS code” on page 97.Check the LEDs on all the power supplies (see “Power-supply LEDs” on page 95).If the LEDs indicate the power supplies are working correctly, complete thefollowing steps:1. Turn off the server.2. Be sure the server is cabled correctly.3. Remove or disconnect the following devices (one at a time) until you find thefailure (turn on the server and reconfigure each time):v Any external devicesv Surge suppressor device (on the server)v Modem, printer, mouse, or non-IBM devicesv Each adapterv Drivesv Memory modules (minimum requirement = two 256 MB DIMMs)Note: Minimum operating requirements are:a. One power supplyb. System board with functioning integrated VRDc. One microprocessord. Memory module (with a minimum of two 256 MB DIMMs)4. Turn on the server. If the problem remains, suspect the following FRUs in theorder listed:v Power supplyv System boardNotes:1. If the problem goes away when you remove an adapter from the system andreplacing that adapter does not correct the problem, suspect the system board.2. If you suspect a networking problem and all the system tests pass, suspect anetwork cabling problem external to the system.140 xSeries 236 Type 8841: Hardware Maintenance Manual and Troubleshooting Guide
