Displays not sensing real pin data and stuck on virtual pin screen

[dzorbas]

I have a number of displays that do not seem to be sensing data when connected to a real pin. They are running the latest firmware and have been activated. The odd thing is that they initially worked when I tested them on my Judge Dredd but when they were installed by the purchaser, they would just sit on the virtual pin screen. Now, when I connect them to JD again, they do the same thing and just sit on the virtual pin screen. I've tried setting them manually to B/W and they still do not respond. I've done full resets, firmware reinstalls, etc. but nothing seems to work. I've done the input test and everything checks out fine. Is there a way to test the LS123 chip/circuit? Is there anything else I can look at or try?

 

Appreciate any guidance here.

 

Thanks!

 

Dino Z.

 

[lucky1]

5 hours ago, dzorbas said:

Is there a way to test the LS123 chip/circuit?

 

Unfortunatelly not, but it is most likely that your problem is there.

[dzorbas]

Well that sucks as I have 3 boards doing exactly the same thing. I will test them in my vpin and see if they work. If so, I can set them aside until someone wants one for that purpose. Would there be a logical reason that the display would initially work fine and then suddenly stop working? My guess would be that the chip failed after heating up. I'm not sure what else could cause that. 

[lucky1]

Why don´t you just put in some new LS123. Just cut the old one out with the scalpel, desolder the pins and solder a new one.

[dzorbas]

I'll see if I can get the chips swapped out or see if I can test some of the connections to and from the existing chips.

 

I apologize for opening up another thread on this. I couldn't remember if I had previously asked about this which, in fact, I did last year. If I come up with a solution, I will share it here.

 

Thanks,

 

Dino Z.

 

[Terranigma]

On 3/21/2023 at 9:56 AM, dzorbas said:

Is there a way to test the LS123 chip/circuit? Is there anything else I can look at or try?

Before you swap the chip, maybe look at the resistors / caps next to it. Not the ones surrounding the DMD connector but surrounding the LS123. Have had a few that were bad and that fixed the issue. Other than that, replacing the LS123 was the solution. Very rare though, but if it was working and then died, maybe something else happened in between. I've only seen DOA for this issue.

 

2 hours ago, dzorbas said:

I apologize for opening up another thread on this. I couldn't remember if I had previously asked about this which, in fact, I did last year. If I come up with a solution, I will share it here.

Don't apologise, probably a buried thread, everything helps.