Daktronics Data Time Series 50 Time & Temperature Displays - Manual (Page 48)

Maintenance &
Troubleshooting
5-2
5.1 The Lamp Driver
The component that switches the lamps ON and OFF in this display is called a lamp driver or
driver. The driver receives data on a pair of wires from the controller. The driver uses this
data to determine which lamps are switched ON. The lamp driver switches the lamps with a
triac. There are 128 triacs, 16 columns with 8 rows each. The rows are also referred to as
segments and are la beled “a” to “h.” Drawing A-37070 shows a layout of the driver.
The hot side of 120 VAC power is wired directly to the digit lamps from fuses in the power
termination panel. The driver switches neutral to the lamps through the triacs. This neutral is
brought into the driver on pins 1 and 2 of J18 and J20.
The lamp driver has 16 jacks (one per column) for switching digit lamps. Figure 4 shows the
pin assignments and color code for the plugs that mate to these jacks. The jacks are divided
into two groups as follows:
Master Digits: J1, J3, J5, J7, J9, J11, J13, J15
Slave Digits: J2, J4, J6, J8, J10, J12, J14, J16
Plugs from all the digits are connected directly into these jacks on the lamp driver. Figure 4
shows the order that these plugs are connected to the lamps in the digits.
The lamp driver LED indicators are located near J17 (refer to Drawing A-37070). Their
functions are as follows:
PWR: Lamp Driver Logic Power (-5 volts)
ON: Power is present.
RST: Monitor Reset
ON: Monitor is resetting Lamp Driver Electronics.
OFF: Normal operation. Monitor checks -5V power, processor execution.
DATA:
Data Signal Input
ON: Signal from controller is present (will blink with data).
OFF: No signal present.
TEST: Lamp Driver Status
This LED flashes at different rates to indicate the status of the lamp driver.
Flash Rate Status
Twice per second Running test pattern
Once per second Connected to controller data (normal operation)
Once per two seconds Not connected to controller data