CJ55

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About CJ55

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    MIDIbox Newbie

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  1. Troubleshooting midiphy SEQ v4+

    I have a question regarding the MIDI8 PCB. I thought the I4/PWR port would work as a MIDI IN also when using a DIN8 socket. Mine doesn‘t. So I disassembled the whole SEQ v4+ again to find the failure. There is no connection between pin4 of the DIN8 and the 220R to the optocoupler pin2. But there is a connection from the adjacent solderpad to the 220R to the optocoupler pin2. This pad would be used when using a DIN5 socket. Is this intentionally? Is this a failure on my board? Can I make this connection to the adjacent pad with a solderbridge? Or is there something I do not consider?
  2. Troubleshooting midiphy SEQ v4+

    I had the same idea and wanted to use them. I have those connectors here but they do not work, because they will cover the mounting holes.
  3. Troubleshooting midiphy SEQ v4+

    Here is the problem my OLED had:     It took some time to find out the real problem. First I thought it was a problem with the OLED PCB, because slightly twisting it on the left side got the display fully working. And of course I testet the header, connector and cable twice before. So here is the problem: The unisolated end of the flat cable had contact with a capacitor on the OLED PCB. I prepared a picture showing it a bit clearer:   I think this problem could happen to everyone and the solution is to use a bit of isolating tape between the connector and the PCB, especially the three components the arrow is pointing at in the picture above.
  4. midiphy SEQ v4+

    Happy New Year! Number 6 has a nice working OLED now! I will write something about how I fixed the problem in the Troubleshooting thread. Thank you Peter and Andy for your offer to replace the OLED!
  5. midiphy SEQ v4+

    Almost Midiphy SEQ V4+ #6 Unfortunately I have a bad Display :-(  On one OLED only the second half of it is lighting up. The first half is very, very dim. I ruled out the connector and the cable. It‘s a problem somewhere on the OLED PCB. When I bend it (twisting it) a little bit on the left side, the display shortly comes to full life. Can not find the problem. Most likely a cold solder joint on the 43 pin flex strip. I am building this SEQ for someone else and he is waiting yearningly for it. Bought it as part of a Midiphy kit. What shall I do?  
  6. Hello Super-Samurai, if you want, I can build one for you. I‘m an experienced professional in Germany ;-) At least regarding electronics. I have a SEQ V4 and consider building a SEQ V4+ for myself.  Just write me a message!
  7. Displays not initializing after working for a while

    Maybe a voltage problem? I see in your pictures that you use the Mini-USB- port. The 5V of the Mini-USB port goes through a BAT60J diode to the board. It has a voltage drop of 0.28V... 0.58V depending on the current flowing through it. Do you have the same problem when using the Micro-USB port or an external power supply?
  8. Powering SEQ with USB Hub problem

    Are you using the Micro-USB or the Mini-USB port for powering your SEQ? The 5V of the Micro-USB port is directly connected to PA9 which is then connected via the jumper J17 to the board. Exactly the same as you power your setup via J2. Should be no difference. The 5V of the Mini-USB port goes through a BAT60J diode to the board. It has a voltage drop of 0.28V... 0.58V depending on the current flowing through it.   
  9. For an aluminium panel you could ask forum member julianf (http://midibox.org/forums/profile/5349-julianf/) There is also (somewhere) a file awaylable for an complete acrylic case. These pages are most useful for the parts needed (all easy to source, the PCBs were always the hardest parts to order): http://wiki.midibox.org/doku.php?id=mididocs:seq:building http://wiki.midibox.org/doku.php?id=wilba_mb_seq_parts_guide http://wiki.midibox.org/doku.php?id=wilba_mb_seq_pcb_bulk_order            
  10. I just saw that Modular Addict is selling the whole range of MIDIbox PCBs. https://modularaddict.com/manufacturer/midibox They even have the (Wilba) SEQ V4 CS PCB available.   Edit: and now I saw that there is already a thread about it here:  
  11. MIDIbox SEQ new frontpanel idea

    I think, I will build a second Midibox SEQ V4(+) soon!  I see you are using a Core407Z. Do you need a JTAG or SWD programmer (st-link v2) for it? Have you tested it already with the midibox seq firmware? I like that is much smaller than the Discovery board! I like your USB module! I build something similar with switching between USB B and USB A (Host). How do you connect your USB module to the core?
  12. Wow, thank you! Great work! Does it work with all kind of Launchpads? Is it correct that the code will run on a raspberry pi? Any raspberry pi? It would be really nice if you could write a little beginner guidance, how to set up the raspberry pi, sometime in the future.
  13. OLED displays

    A voltage regulator like the 7805 needs an input voltage that is higher than the regulated output voltage. The 7805 needs an input voltage between 7V and 25V to output 5V.
  14. OLED displays

    The problems with the OLEDs is most likely a power related problem. The 3.3V Regulator (LD3985M33R) on the STM32F4 Discovery board only provides 3.0V (because of a BAT60 diode in series to the output) and can deliver only 150mA of current. And it has to power the whole STM32F4 board. So there are only <100mA left for external components like the OLEDs. The Raystar datasheet mentions 60mA for 50% check board (whatever this means). With 2 OLEDs your are already at 120mA. There might be conditions where this will work. But it will not be very reliable! Other OLEDs (especially white on black ones) probably need much more current then the tiny onboard regulator can deliver. This is only a problem for OLEDs which need 3.3V to work. 5V OLEDs should not have a problem as long as your external power supply can deliver enough current.