Snoozr Posted September 6, 2010 Author Report Share Posted September 6, 2010 I recommend taking out the U20 IC and checking voltages on the pins that connect to JD5... they should be 5V when there are no buttons pressed. You can also test with U23 removed so there is nothing pulling current... the pins should stay 5V even when buttons are pressed. I'm getting 5V except for on the bad line which is 0V. Procedure was take out U20, touch red lead to JD5 solder joints, touch black lead to GND. Repeated procedure with U23 out as well and got same result. Similarly, you could check there is a 10K resistance between 5V and each of the JD5 pins. I'm getting about 13K on the Sanwa, except for on the bad line which seems to have very little resistance (needle flies over and pins to zero). Procedure was take out U20, touch red lead to +5v, touch black lead to JD5 solder joints. Quote Link to comment Share on other sites More sharing options...
Wilba Posted September 6, 2010 Report Share Posted September 6, 2010 The LCD could be shorting with the "Select 5" switch. Check that first. Then check the attached picture showing what is connected to that pin. Some vias are overlapped by encoders. It's unlikely but possible that an encoder is touching that via. AFAIK all the encoders I've seen have plastic feet so the metal base is not touching the PCB, but it's worth checking anyway. Quote Link to comment Share on other sites More sharing options...
Smithy Posted September 7, 2010 Report Share Posted September 7, 2010 I believe you are on the right track... Ewwww! What a revolting pun! Quote Link to comment Share on other sites More sharing options...
Snoozr Posted September 7, 2010 Author Report Share Posted September 7, 2010 Ewwww! What a revolting pun! Lol. :thumbsup: Case closed. I had previously applied electrical tape to the top part of the LCD so as to protect the LCD inputs from contacting anything. I decided to remove the LCD again so as to similarly apply tape to the bottom portion. Once it was removed, I powered up the little guy and there was no problem. Ka-ching. I applied electrical tape to the underside of the CS where Select 1-5 were and re-attached the LCD. Powered up and the problem was gone :D Select 5 does a number of important things like Save and Detune so I am glad to get that functionality, plus the perma-blinking matrix was cool for a while but started to get distracting. THANKS WILBA!!! :sorcerer: Quote Link to comment Share on other sites More sharing options...
Wilba Posted September 8, 2010 Report Share Posted September 8, 2010 Sorry it took so long, I should have suggested a short with LCD much earlier. You're not the first to have this problem magically disappear when I suggest detaching the LCD :wink: Quote Link to comment Share on other sites More sharing options...
Snoozr Posted September 9, 2010 Author Report Share Posted September 9, 2010 Haha - it's all good. I learned some new stuff and I got a great synth. Thumbs up for Midiboxes! Quote Link to comment Share on other sites More sharing options...
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