Dell OptiPlex 7760, Service Manual

Page: 130 / 137

Troubleshooting
Topics:
• Built-in self-test (BIST)
• Dell SupportAssist Pre-boot System Performance Check diagnostics
• System-diagnostic lights
• Recovering the operating system
• Backup media and recovery options
• Real Time Clock—RTC reset
• WiFi power cycle
• Drain residual flea power (perform hard reset)
Built-in self-test (BIST)
M-BIST
M-BIST (Built In Self-Test) is the system board's built-in self-test diagnostics tool that improves the diagnostics accuracy of
system board embedded controller (EC) failures.
NOTE: M-BIST can be manually initiated before POST (Power On Self Test).
How to run M-BIST
NOTE: M-BIST must be initiated on the system from a power-off state either connected to AC power or with battery only.
1. Press and hold both the M key on the keyboard and the power button to initiate M-BIST.
2. With both the M key and the power button held down, the battery indicator LED may exhibit two states:
a. OFF: No fault detected with the system board
b. AMBER: Indicates a problem with the system board
3. If there is a failure with the system board, the battery status LED will flash one of the following error codes for 30 seconds:
Table 18. LED error codes
Blinking Pattern Possible Problem
Amber White
2 1 CPU Failure
2 8 LCD Power Rail Failure
1 1 TPM Detection Failure
2 4 Unrecoverable SPI Failure
4. If there is no failure with the system board, the LCD will cycle through the solid color screens described in the LCD-BIST
section for 30 seconds and then power off.
5
130 Troubleshooting