MobiFlight Community Support

Hi all,

I have a very frustrating issue I can't figure out. I just finished a build where I have 3, 7-segment displays daisy chained together. I have separate 5V power running to each display. Earlier today when I first finished the build, I ran a test and all three displays worked perfectly. Now, I've come back a couple hours later (having not used the displays at all, and the only changes I've made were to configure all the other switches and buttons I have), and now all of a sudden the only display that is working is the 2nd one in the chain of 3. The first and 3rd displays don't seem to work at all now.

I don't understand it because the 2nd display is getting fed from the 1st display, and in my head, if the 2nd display is working, then that means that the data is flowing correctly from the Arduino, through the 1st display to the 2nd one. So if that's the case, why would the 1st display not be working all of a sudden? I could understand the 3rd display in the line not working easier than the 1st, because with that I could at least imagine there's a connection issue between the 2nd and the 3rd, but yeah, no idea why the first display isnt working. And especially after it worked perfectly a couple hours ago.

I'm still relatively new to all this so I would appreciate immensely anyone's insight and help on this.

Thank you.

Tom

Ok everyone, nevermind. I figured it out.

Turns out the first 7 segment module in the daisy chain had gone bad. Why I didn't pick up on it sooner was because when I was troubleshooting, the first display would light up every now and again, but only when I connected it to a separate Arduino. I then did a test where I bypassed the first module and when I did, both module 2 and 3 worked fine. At that point I figured maybe the whole module had gone bad, and as soon as I swapped it out, everything started working again. I didn't think to check the modules individually sooner because they had all worked just a little before all this, and this was my first time using any of them.

Anyway, thanks to anyone who took the time to read this. Hope it helps someone.

For sure...
Also those Modules can get broke.
those China imports are not high quality !

But if first test work fine i expect the issue is not the MaxChip or Display ( Expect you grill it by a wrong power setup)

Please confirm your setup is Solder 100% .... No connectors or Dupont. Every wire that is connected to a Display ( whatever on left or right port) is solder !!
Max Chips are very sensetive!
Just a touching of Table can be enough to struggle them. Then a restart is needed from the Arduino itself cause it lost sync.

It also can fully lost connection ( e.g. a bad connector). Then it will not work anymore.

best test for those situations.... Simply touch/move the wires a little harder. If this already crash the system (display goes off or show 8888888) you know you have a wire problem !


To avoid this....
1. Resolder all 10 Connectors ( left right) whatever they was deliver soldered.
My experience 30-50% of chineese Pin solders are bad.

2. Solder your Wires there or use high quality Connectors. Avoid Dupont completly !

Also mount displays in a way wires are never touched again. Fix them on the panel ... use Hot glue to fix the whole connection 100%.

If you do this perfect and test is fine i would say it work in 99% of cases for years without anymore trouble !