jwrigh10 Posted January 4, 2009 Report Share Posted January 4, 2009 I am apparently experiencing an issue with one connection (J5) on a DIN module. When I press buttons corresponding to pins 5 & 6 I get two midi messages per pin. For example, a normal message is: 94 2D 7F 5 A note On. However, when I press a button corresponding to these pins I get: 94 29 7F 5 F note on and 94 2A 7F 5 F# note on. In other words, I get two sets of midi messages per pin.Here is what I have done to troubleshoot1. Replaced the cable connectors-same result2. Plugged in another cable (from J4 for example)-which did not give multiple messages on J4 pins--same result on the J5 pins3. Plugged in a good cable (e.g., the one from J4 which works fine) into J5-same result of multiple messages4. Checked midio file-could not find a bug5. Visually checked DIN-could not see a problem.Does anyone have any suggestions. All the other ports (J3, J4, J6) work fine. I just have these 2 pins on J5 that are triggering multiple midi messages. Quote Link to comment Share on other sites More sharing options...
Max Romantschuk Posted January 4, 2009 Report Share Posted January 4, 2009 I'm still very new at this myself, but logically it seems like either the two offending pins are shorted, or the shift register is faulty.I'd swap the shift register with one connected to a set of non-malfunctioning pins. If the problem persists on the same pins there has to be a short somewhere on the board. If the problem moves to another set of pins you have a faulty shift register.Will someone please verify my logic? My first DIN is still not yet soldered... ;) Quote Link to comment Share on other sites More sharing options...
stryd_one Posted January 4, 2009 Report Share Posted January 4, 2009 Sounds about right to me.jw: by your description it seems that you are not receiving a duplicate message, but a message corresponding to the neighbouring pin. You only explained the behaviour of one pin, so it's not clear whetherShorting pin5 also triggers pin6, shorting pin6 also triggers pin5orShorting pin5 also triggers pin6, shorting pin6 also triggers pin7Which one it is, will tell us a fair bit... Quote Link to comment Share on other sites More sharing options...
jwrigh10 Posted January 8, 2009 Author Report Share Posted January 8, 2009 I'd swap the shift register with one connected to a set of non-malfunctioning pins. If the problem persists on the same pins there has to be a short somewhere on the board. If the problem moves to another set of pins you have a faulty shift register.I swapped the shift register wiith a one connect to a set of non-malfunctioning pins and got the same result. I did this twice and had the same result. Therefore, there must be a short.jw: by your description it seems that you are not receiving a duplicate message, but a message corresponding to the neighbouring pin. You only explained the behaviour of one pin, so it's not clear whether shorting pin5 also triggers pin6, shorting pin6 also triggers pin5or shorting pin5 also triggers pin6, shorting pin6 also triggers pin7 When I press the button corresponding to pin 5 I get "94 29 7F 5 F note on" and "94 2A 7F 5 F# note on." Also, when I press the button corresponding to pin6 I get "94 29 7F 5 F note on" and "94 2A 7F 5 F# note on" (i.e., the same message). Both pins are giving me the same message. Pin5 should give me "94 2A 7F 5 F# note on" and pin6 should give me "94 29 7F 5 F note on." I put another cable on the J5 pins and had the same problem at the same place so it is definately in the board.How do I track down a short in the board? I have visually checked it with a magnifying glass and have found no shorts. Is there any other way I can track down a short on the board. Quote Link to comment Share on other sites More sharing options...
stryd_one Posted January 9, 2009 Report Share Posted January 9, 2009 Yep, you've shorted the inputs for those two pins together. There aren't many places you can do that, so just check the board. Don't forget the socket too.... Quote Link to comment Share on other sites More sharing options...
Max Romantschuk Posted January 9, 2009 Report Share Posted January 9, 2009 How do I track down a short in the board? I have visually checked it with a magnifying glass and have found no shorts. Is there any other way I can track down a short on the board.You do know how to use a multimeter to look for shorts? But then again we already know where it is electrically, now you have to find it physically. Quote Link to comment Share on other sites More sharing options...
jwrigh10 Posted January 10, 2009 Author Report Share Posted January 10, 2009 I am still a newbie and not sure how to check for shorts with voltmeter. Cannot find anything physically wrong. The back of the board looks fine. Any info or link on how to use the voltmeter to check for shorts would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
Max Romantschuk Posted January 10, 2009 Report Share Posted January 10, 2009 A short is the same as a connection, and connections have little resistance. You set your multimeter to measure resistance, say 1K Ohm, and whenever it says 0 there is a direct connection. What is a short and what isn't you have to deduce for yourself, but I'm guessing the resistance between the two offending pins is 0.What you want to look for is any place between the pins and the chip header the traces cross. If all else fails desolder the pin header and see if there is still a short. Quote Link to comment Share on other sites More sharing options...
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