The common problems in the LED unit board resolution

The Led unit board the problems mainly is divided into four points:

1, the whole board is not shiny, mainly because the unit board did not connect power line connection error, or the plate lead to circuit is negative differ.

2, not shiny, transport normal function: this is caused by damage of circuit board with a built-in, can be 74 hc138 4 feet and 5 feet cause a short-circuit phenomenon.

3, shining every: damaged board in 4953.

4, interlaced shining: can analyze to the circuit problem.

(1) : check unit board built-in 74 hc245 and 74 hc138 whether virtual welding.

(2) : using the multimeter to measure 74 hc138 voltage have around 2.5 V 1 foot, there are 74 hc138 is replaced

(3) : measuring electricity transmission signal is lily with ICA.