18 July 2016
faulty power supply component or a loose connection/bad
solder joint somewhere along that power line.
Phillips probably won’t provide a schematic, so you’ll
have to trace the circuit yourself. The biggest problem will
be determining the LED power terminals, unless the circuit
board is marked or the LCD module datasheet is available.
Be aware that many companies do not mark their boards
and/or use OEM parts whose data cannot be accessed
by the consumer. Troubleshooting tips in most owner’s
manuals are useless in finding electronic problems.
If the correct voltage is present at the LED power
terminals, then the LEDs are bad. This means the entire
LCD module must be replaced, which may or may not
be available from the manufacturer or an electronics
component supplier. It’s a sad state of affairs, but most
consumer electronics devices are meant to be “throw
away” items which are difficult (if not impossible) to repair
by the consumer and too expensive to have repaired by a
service center unless the device is still under warranty. (I
have had a couple of dive watches that were so expensive
it was feasible to send them back for repair).
There may be a chance of installing some LEDs around
the periphery of the display module to show the digits, but
since this module has a backlight there will be no mirror to
help reflect the light back through the digit pixels.
I hope this gives you a starting point for
troubleshooting your backlighting problem.
n FIGURE 7. n FIGURE 8.
n FIGURE 9.
LCD Clock Controlled by Arduino Pro Mini Schematic.