Please Help!! 7 Seg Displays with OC Displays card

[shafian]

I have assembled 2 of the 4 display II cards i ordered in kit form from OC along with the master and expansion card..

The master card an expansion card which i assembled are working perfectly. Power to MC is through a seperate PSU constant 5v.

I decided to test the displays card connected to a 3 display PCB from OC. Unfortunately the top right segment and the bottom left segment dont light up with one of the cards and also not all grounds seem to work either.

Out of curiosity i assembeled another displays card and the same thing happend. either it wont work altogether or only 5 segments light up showing a 5 on the display. when i run the counter in controller program i can see its working but without those two segements. I have checked jumper settings and controlador.ini etc.

I have thoroughly checked the solders and IC seating etc several times and also assembled another 3 display PCB to rule out any faults. Changed cables and everything i could think off.

I have noticed on some forums that others have had trouble with this but cant find any resolutions.

Is someone able to give some guidance to identify the cause or fault??

[skywatch]

Seems like you have done a lot to try and get to the bottom of this. I don't know the answer but you could try manually 'flashing' the 7seg displays out of the holder to rule out a duff batch of displays. Don't forget to include an appropriate resistor in there ;-) !

Skywatch

[tomenglish2000]

Are you using common cathode 7 seg displays? Common anode ones wont work and might be the cause of the problem.

[shafian]

Thanks for your answers.. Yes these are common cathode displays and i have 62 of them all ordered from OC. When i flash them all segments work ok on all the pcb's i've assembled.. I ran a check on the mounting again but to no avail :(.. Im starting to think whether its a bad batch.. now i don't get anything at all with the first couple of gnd's.. but i get some segments that appear around pins 9 -16.. No response from controller program.. I used another master card and there's still no difference.

Would it matter where the IC's are placed ? I don't mean the position of them but whether all the 16 pin ones are the same ? would anyone be kind to share a closeup photo of their OC Displays II card? That would be extremely helpful.

[iwik]

Hi,
If you have tested all the 7 segment display bds by flashing them independantly of thr display II pcb.Then you can rule out faulty displays/Pcb.
There are 16 display outputs per bd.Did you try a 7 seg display bd on all
16 outputs to see if they give the same fault on all 16 outputs?.
As these are a multiplexed disply system,the only thing that is unique for each display is the Common Cathode.All the same segments are joined together.If these are alright then it leaves only decoding.
Please be a bit more descriptive as to where and what chips you are referring to.I would have thought if the kit was bought from o/c then they would have only supplied the correct brand of chips if this was important.
How about posting a pic of the 7 seg pcb and display II card running.
Give aclose up of the Display II board.Iv completed my one but have not tested it yet.
rgds
Les

[bindook]

Have u tried turning the power onto the cards first before turning the pc on?


Michael