Good morning!
I have an older 70's pinball with 7400's series ics. (look at old posts), anyway I've made good progress with this over the last 6 months thanks to the wonderful people on this forum and dusting off 20+ years of neglect in my head. I've changed out several ics with success but now it looks like one of the display drivers (BCD to 7 segment) might be bad. I'm getting letters instead of numbers for the 3 and 4 for example. It's displaying c and d, Ive checked the outputs from my 7490,and the inputs to the 8880, they are okay. The display is good, other numbers display fine. Here is the issue, the chip that drives this is an DD8880. I cant find this anywhere...is there a secret source or can I substitute another 7 seg driver as long as the pins match? Its the 100s display.
I have an older 70's pinball with 7400's series ics. (look at old posts), anyway I've made good progress with this over the last 6 months thanks to the wonderful people on this forum and dusting off 20+ years of neglect in my head. I've changed out several ics with success but now it looks like one of the display drivers (BCD to 7 segment) might be bad. I'm getting letters instead of numbers for the 3 and 4 for example. It's displaying c and d, Ive checked the outputs from my 7490,and the inputs to the 8880, they are okay. The display is good, other numbers display fine. Here is the issue, the chip that drives this is an DD8880. I cant find this anywhere...is there a secret source or can I substitute another 7 seg driver as long as the pins match? Its the 100s display.