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Had a few hours to mess with the SammichFM. I was rocking the box in Ableton and making some nice tunes and then all of a sudden the LCD displays gibberish. Tried turning it off and back on - initially the OS won't bootstrap, so I tried turning it on and off again. Managed to get the MIOS prompt after turning on and off. Everything appeared as though it were back to normal, but then when i turn the rotary encoder to switch patches, I am presented with more random characters on the display. What might be happening here?
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Gibberish characters on LCD display
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#1
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Posted 16 September 2011 - 06:24
#2
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Posted 16 September 2011 - 06:37
It seems to be erratic - at short intervals, when scrolling through patches with encoder or buttons, it will display random characters but then a short time later it will be fine and display as desired. Weird.
#3
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Posted 16 September 2011 - 08:22
Bad solder joint?
#4
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Posted 16 September 2011 - 13:28
Bad solder joint or swapped wiring on the LCD. Also happens on some displays if they do not exactly conform to the correct spec.
#5
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Posted 16 September 2011 - 13:47
This could be just a bad solder joint on the header to the LCD.
So I would recommend checking all the solder joints on the female header and perhaps even disassemble the LCD from the control surface PCB and give all those pins a check and reheating. It could even be caused by bad solder joints on the PIC pins leading to that header, so check those too.
It would be good to confirm that it's JUST the LCD that is the problem and nothing else... so if you get garbage on the display, check if the sound engine is still working... i.e. send it note events while it's displaying garbage.
FWIW: MIOS has a "feature" that if it sends LCD commands and then waits too long for the "busy" state to finish, it disables the display completely.
It might think the LCD is "busy" if the command was garbage, or retrieving the busy state is returning garbage, which can happen if one of the data pins is intermittent. So it's not a surprise if sometimes the display "locks up".
So I would recommend checking all the solder joints on the female header and perhaps even disassemble the LCD from the control surface PCB and give all those pins a check and reheating. It could even be caused by bad solder joints on the PIC pins leading to that header, so check those too.
It would be good to confirm that it's JUST the LCD that is the problem and nothing else... so if you get garbage on the display, check if the sound engine is still working... i.e. send it note events while it's displaying garbage.
FWIW: MIOS has a "feature" that if it sends LCD commands and then waits too long for the "busy" state to finish, it disables the display completely.
It might think the LCD is "busy" if the command was garbage, or retrieving the busy state is returning garbage, which can happen if one of the data pins is intermittent. So it's not a surprise if sometimes the display "locks up".
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#6
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Posted 16 September 2011 - 19:48
Thanks, guys. I will check the LCD solder joints again. I am pretty sure it is just the LCD because the sound engine and core module appear to be working as they should (I can still navigate interface, select patches and playback audio).
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