Notes and information about EKF PC3-ALLEGRO: ============================================ 1) PC3-ALLEGRO does not start after power is reapplied ====================================================== Sometimes the system does not start after power is reapplied to the board. In almost all cases this is NOT caused by a hardware failure of the board! It is caused because the board enters S4 or S5 state after power-up (like a "normal" PC), instead of running state S0. Sleep states S4 or S5 are indicated by front panel LED PG=off and one or both LEDs GP/HD=ON). Chapter "PG (Power Good) LED" in User Guide of PC3-ALLEGRO describes this in detail: http://www.ekf.de/p/pc3/pc3_ug.pdf To bring the board back to working state the (red) ejector handle in front panel of PC3-ALLEGRO handle must simply be opened for a short time (less than 4 seconds). Note: This implies that BIOS setup option "Function of front panel ejector:" is not changed from its default setting "Power button". More info on this: Chapter "Reset" in User Guide of PC3-ALLEGRO. See also http://www.ekf.de/c/ccpu/img/reset_400.gif Technical background: On EKF PC3-ALLEGRO there are 4 reasons why the system enters S4/S5 (sleep) state after power-up, instead of S0 (running) state: 1. The corresponding bit in the SMBus unconditional power down message is set 2. PCH QM77 internal thermal sensor catastrophic condition (PCH QM77 overheating) 3. Assertion of THRMTRIP# signal at PCH QM77 (Processor overheating) 4. A Power Button Override event (pressing Power Button more than 4 seconds) 2) Invalid CMOS data ==================== If the BIOS detects a bad checksum in CMOS data, CMOS is reset to default values during POST. The possible reasons for a bad CMOS checksum are: - An empty battery - A board with NO battery - Any software writes to CMOS and does not update the CMOS checksum bytes For PC3-ALLEGRO these options exist to manually reset CMOS to default values: - key when in BIOS Setup - Set jumper P-GP (see PC3 User Guide for more info) Last modified: 2014-08-07 EKF