CONSOLE FACEPANEL LED FUNCTIONS
Each PC board on the face panel contains one red, one green, and three yellow status indicator LEDs. The color and function of these LEDs is common to all PC boards. They are intended to be used for local status indication and visual troubleshooting. The LED functions are described in the following text.
HEARTBEAT LEDThis red LED indicates that the PIC is running and executing its main instruction loop. Normal operation is indicated by the LED flashing. If this LED is not flashing, this is a bad thing. The board is dead, dead, dead.
This yellow LED indicates that the PIC is scanning any keys present on the board or connected from elsewhere on the console. Normal operation is indicated by the LED flashing quickly and then remaining off for a short period. For this reason, this LED appears to be dimly lit in normal operation. This LED is flashed on and off at the start of the scanning sequence so may be used to synchronize test equipment for troubleshooting purposes.
This green LED has a dual function. It indicates activity on the I2C bus and when a switch contact is closed. Normal operation is indicated by the LED flashing quickly on and off when a packet of information is transmitted or received over the I2C bus. For this reason, this LED appears to be dimly lit in normal operation.The second function of this LED is to indicate when a switch on or connected to the board is closed. The LED is lit at full intensity when any switch contact is closed and will remain lit until the switch contact is opened.
This yellow LED also has a dual function. It indicates activity by any shaft encoder mounted on or connected to the board and has a test function related to potentiometers. Normal operation is indicated by the LED being off. When a shaft encoder is rotated, the LED is flashed quickly on and off as each phase changes state. For this reason, the LED appears to be dimly lit while the shaft encoder is being rotated. The apparent intensity will increase as the shaft encoder is rotated faster.The second function of the LED is to indicate 50% position of potentiometers on the board. The potentiometer which is being indicated is one less than the potentiometer set to maximum. In other words, push a pair of fader or submaster potentiometers to maximum. The LED will be lighted at full intensity. Adjust the lower numbered (on the schematic) potentiometer toward a lower setting. When the potentiometer reaches 50% or below, the LED will go out. The alternate test is to set all potentiometers to maximum. Adjust any potentiometer toward a lower setting. When the potentiometer reaches 50% or below, the LED will go out. Return the selected potentiometer to maximum to test any another.
+5 VOLTS DC LED
This yellow LED indicates there is +5 volts DC power applied to the board. Normal operation will have this LED lit at full intensity as soon as power is turned on to the console.
CONSOLE CPU BOARD FUNCTIONS
CR4 - blinks when sending Ethernet packet CR5 - turns on with valid UTP connection CR6 - blinks when Ethernet collision detected CR7 - rapid blinking during PIC main loop CR8 - IIC transactions CR9 - slow blink during i960 main loop**(CR9-CR11 will briefly flash on at bootup, if they don't turn off then there is something wrong)