need help in moving display

[pinks]

my project is based on moving display using pic18f4520,74hc595 shift reg,10 7x5 led dot matrix..transistor bd139...i am using common anode type display...i have connected the anode of display to the port pin through transistor....and cathode to the shift reg....data is then given serially to the shift reg from controller.......so this is my story....actual problem starts when i turn on the supply ,the display doesnt show any particular character.. it seems that all LEDS are ON at once....CAN ANYONE HELP ME THIS????????

 

[jumper2high]

You must have either connected it wrong or you're not correctly sending data to the shift register.

Or you might have a short circuit. There are tons of possible reasons. Have you tried manually connecting one of the segments (dots) on the power supply to see if only one lights up?

 

[Prabakaran]

Dear Pinks
Please check the connections indivally by connecting a common terminal to ground and Supply to the Each LED . So that u can able to view the display whether working or not.

Note: Please check whether its COMMON ANODE OR COMMON CATHODE.

 

[pinks]

i have already tested each dot matrix individually ...it was working fine....there's no doubt that current flowing through display....shifting everything it shows..i think the problem may be the refreshing rate....timing mismatch....

Added after 7 minutes:

Dear Pinks
Please check the connections indivally by connecting a common terminal to ground and Supply to the Each LED . So that u can able to view the display whether working or not.

Note: Please check whether its COMMON ANODE OR COMMON CATHODE.

i have already checked all displays individually ...it was glowing fine....and the displays are of common anode type...

 

[piyusgupta]

hi i have seen some timings mismatch problem may be sorted out by using uln2981