goredaimon Posted October 17, 2021 Share Posted October 17, 2021 Hello friends, how are you? I have a PIN2DMD evo here not working with real pinball machines. But with virtual pinball setup works ok! I tested another displays from the same batch and they are fine. I'd like to know what I need to investigate. Should I suspect the 74LS123D? Thanks! Link to comment Share on other sites More sharing options...
Content Provider lucky1 Posted October 17, 2021 Content Provider Share Posted October 17, 2021 Did you run the input test as described on pin2dmd.com ? Link to comment Share on other sites More sharing options...
goredaimon Posted October 18, 2021 Author Share Posted October 18, 2021 I'll check that today! Link to comment Share on other sites More sharing options...
goredaimon Posted October 19, 2021 Author Share Posted October 19, 2021 On 10/17/2021 at 12:37 PM, lucky1 said: Did you run the input test as described on pin2dmd.com ? I just checked and PIN 9 is not working. What should I suspect now? Link to comment Share on other sites More sharing options...
Content Provider lucky1 Posted October 19, 2021 Content Provider Share Posted October 19, 2021 If you have a look at the schematics you can see that the circuit around the LS123 is connected to PIN9 Link to comment Share on other sites More sharing options...
goredaimon Posted October 19, 2021 Author Share Posted October 19, 2021 21 minutes ago, lucky1 said: If you have a look at the schematics you can see that the circuit around the LS123 is connected to PIN9 I just checked all traces with the board file and they are correct. I don't have bad traces. Is it possible to check the 74ls123? Also, if somebody connect/disconnect/invert the ribbon cable at j2 with the display on, it could damage the 74ls123? Link to comment Share on other sites More sharing options...
Content Provider lucky1 Posted October 19, 2021 Content Provider Share Posted October 19, 2021 2 hours ago, goredaimon said: Is it possible to check the 74ls123? Yes with a oscilloscope or a logic analyzer. 2 hours ago, goredaimon said: Also, if somebody connect/disconnect/invert the ribbon cable at j2 with the display on, it could damage the 74ls123? No Link to comment Share on other sites More sharing options...
goredaimon Posted October 19, 2021 Author Share Posted October 19, 2021 Thank you! I'll got some 74LS123 and replace to test. Do you know the package type? Link to comment Share on other sites More sharing options...
Frankensteinowner Posted October 31, 2021 Share Posted October 31, 2021 I had an issue with the '123 on mine - the input just seemed to be locked solid, low impedance. As Lucy says - you need a scope to be able to test it. Package is a SOIC16 - pretty easy to replace if you're OK with a soldering iron Link to comment Share on other sites More sharing options...
ThaBini Posted November 1, 2021 Share Posted November 1, 2021 check the solders sometimes bad solder can do that I had one onthe last card. best regards Link to comment Share on other sites More sharing options...
goredaimon Posted November 4, 2021 Author Share Posted November 4, 2021 Solved! The problem was the 100k resistor at the 74LS123. The resistor came bad from PCBWAY. Next time I'll do the boards by myself. Link to comment Share on other sites More sharing options...
trueno92 Posted November 4, 2021 Share Posted November 4, 2021 Wow good trouble shooting. How did you test the resistor? Link to comment Share on other sites More sharing options...
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