PROTECTION AND SELF DIAGNOSTICS
- All of the listed monitoring lines will cause the unit to power down by removing the relay “high” command (PWCTL) to the main relay driver on the G1 board. The particular event that triggered the protection will also cause the timer or lamp LED to flash. The lamp LED will only flash if a lamp failure is sensed. The timer LED will flash in designated sequences. As an example: If excessive temperature is detected by IC47 on the H3 board, the unit will power down and the timer LED will flash four times at 500ms intervals followed by a two second separation period and another set of four flashes and so on. The event will also be stored into a NVM IC on the C2 board for viewing if necessary.
Below is a brief description of each
protect item:
TEMP:
A digital thermometer (IC47) located
on the H3 board monitors ambient temperature within the cabinet of the unit.
The IC communicates with IC3208 via the I²C bus. Once the temperature has
exceeded acceptable limits the unit will power down and the timer LED will
flash in sequences of four.
OVP [Over Voltage Protection]:
There
is a power board known as the G3 board that is an integral part of the DIC2
board. It outputs a 3.3V, 2.5V and 1.8V source. If either exceeds specified
voltage levels, a high is sent to IC3405. The LED flash sequence will be eight
times.
17V OVP:
Although
the 17V lines on the G board are monitored by zener diodes to activate the
protect latch, the 17V-1 is redundantly monitored here to provide the only
diagnostics indication from a G1 board protection. The LED will flash six
times.
Speaker DC Detect:
To prevent damage to the speakers if
one of the amplifiers should short and place DC onto the lines, both the main
L/R amp (IC47) on the AU board and the woofer amp (IC85) on the A board are
monitored. Any DC voltage will send a
high to IC3405. The LED will flash seven times.
Fan Protect:
Although
the schematic shows five fan drivers, only three fans are used in this model.
All are located in the lamp and optical assemblies. When the fans are rotating
normally, a low is output from the protect line of each. If one or more fail to
rotate, a high will be sent to IC3208. The LED will flash four times.
Lamp Cover Switch:
When the lamp
cover is closed, a switch (S3999 on the T board) grounds this line. If the cover
is not closed or the switch fails, a high is sent to IC3208. The LED flashes
three times.
Lamp Detect:
A
high-pressure, mercury vapor arc lamp is used. As the lamp ages the arc gap
increases. Current draw will decrease
and when this threshold is reached, the lamp LED will flash, notifying it is
time to replace the lamp.
TO ENTER THE DIAGNOSTIC MODE
- A failure history of each monitored diagnostics circuit can be viewed by pressing “DISPLAY”, “5”, “VOLUME –” and “POWER” on the remote ommander. Unlike previous versions of this feature, the failure history is split between two pages. By using the left/right command on the remote joystick, you can toggle between them.
- The initial page displayed is generated by the main microprocessor on the C2 board and is the same RGB line generating the customer menu. The second page displaying the remaining list is generated by the service mode OSD. This is generated by the LCD engine microprocessor (also located on the C2 board) and is only displayed in green.
