Daktronics Data Time Series 50 Time & Temperature Displays - Manual (Page 53)

Maintenance &
Troubleshooting 5-7
to where it connects to the socket to check for a faulty connection between the wire
and the socket.
If a lamp is stuck ON, it is probably a failed (shorted) triac. This can be fixed by
replacing the lamp driver (Section 5.4.3) or replacing the triac only (Section 5.4.4).
If a whole digit will not turn ON, check the fuse for that digit (Section 5.4.1). In
some cases when a lamp burns out, it will cause a triac to short.
5.3.3 Lamp Driver Test
The lamp driver can be set to run a lamp test. This test can be used to check the lamp
driver outputs independently from the controller signal input. The test will alternate
between the two patterns of every other segment turned ON in each column output.
Locate two pads labeled “TEST” next to J19 on the driver. With the tip of a
screwdriver blade, momentarily short these two pads together just long enough to
make the test pattern appear. To exit the test mode, momentarily short these pads
together again just long enough to stop the test pattern.
5.3.4 Time and Temperature
If the display does not keep time accurately and/or the temperature is not stable, try
running the controller off the Real Time Clock (refer to Section 4.8). If the controller
is running off the Real Time Clock, try the Line Frequency. This will help determine if
one of these time bases is faulty. Accurate timing is necessary for both time and
temperature to operate properly. If the power line frequency is bad, either consult the
power company or an electrician to get it corrected or run off the Real Time Clock.
The Line Frequency is preferred, but the Real Time Clock is very accurate. If the
Real Time Clock is not working properly, the controller should be replaced or repaired.
A problem with the temperature may also be caused by a faulty temperature sensor or
connection. Check the LED indicator labeled “TMP” on the controller to see that it is
ON. It may be necessary to try another sensor. Remember: if the temperature sensor
input is out of the normal operating range (not connected), the display will not show the
temperature at all.
5.3.5 Dimming
Dimming can be most easily checked during the day by covering the temperature
sensor/light detector for a minimum of five seconds. If this does not work, set the
controller to Manual Dim and Manual Bright using Function #3. If this does not work,
try replacing the driver. If Manual settings work but Automatic settings do not, check
the LED labeled “PHO” on the controller (refer to Section 5.2.3). It should turn OFF
when the sensor is covered. Replace the sensor if necessary.
5.4 Repair
Repairing the display will usually require one of the following:
• Replacing a lamp (routine maintenance)
• Replacing a blown fuse