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About jaytee

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    MIDIbox Tweaker

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  1. Starting MB6582 build

    Before you order a new regulator, run some tests, find it if your current regulator is drooping, measure current draw with and without LEDs, etc.
  2. Starting MB6582 build

    I forget exactly what I put in there, probably a 10uF. It’s probably not even necessary tbh. Otoh, I don’t think the capacitor is your problem, especially if you only put in a 10uF. Something related to current draw seems likely though, since it seems like your main deviation from a typical build are those LEDs. Did you socket your current limiting resistors? You could try pulling those and seeing if you get a consistent good boot up. If you didn’t socket them, you could cut/desolder the board connections that go with the LEDs, or if you wanted to try bigger resistors anyway, just clip them.
  3. Starting MB6582 build

    My bad, it was too big of a capacitor on the output of the sVreg, coupled with too much current draw on start-up.
  4. Starting MB6582 build

    The second video looks more or less correct. Hard to tell exactly because of the bright LEDs and otherwise dark video, but it should definitely start up with a quick light show on the matrix. IIRC, the boot-up lightshow has two stages, one with the LEDs in a more-or-less randomly flashing pattern, and one where the LEDs alternate a checkerboard pattern—I forget which comes first. You have the new Step E power circuit, right, with the sVreg? I had a little trouble with excess power draw on start-up causing issues with my boot up, but it was solved IIRC by changing to a smaller cap on the input of the sVreg. Might be a similar issue if your fancy LEDs draw too much current? It doesn’t seem like the shift registers are the problem, as least from what little I’ve seen in those videos.
  5. Starting MB6582 build

    Congrats! I remember that moment when I finally got a legible message on my screen ;) all downhill from here.
  6. Starting MB6582 build

    You may be able to get contrast working with a jumper wire from pin 15 to the contrast trimmer (and cutting a trace on the board), or it might work as-is with the ideal setting all the way to one end of the trimmer’s range instead of somewhere in the middle, but tbh if it were me, I would certainly be tempted to just get a different LCD.
  7. Starting MB6582 build

    I’m pretty sure you want to leave Pin 15 disconnected. Seems like a bad idea to be injecting negative voltages into your MIDIbox. But I’m not sure that having it connected would be enough to keep your backlight from turning on, as that seems to rely solely on proper voltage at Pin 1 and Pin 16, which you should have. So I would disconnect the LCD entirely and double check that all your voltages are still correct (ie double checking that nothing went wonky from applying -5V to pin 4 of J15). If that looks good, snip the wire attached to Pin 15 and see if anything changes. Disclaimer: We’re already a bit beyond my full understanding, so consider these comments as rough guesses rather than truth. Still, this is more or less what I would be doing to troubleshoot.
  8. Starting MB6582 build

    Okay, double-reading the data sheet and I don’t think it needs negative voltage for the backlight. But pin 15 seems to be used for something other than powering the backlight, which is odd. According to the data sheet, it supplies negative voltage as part of an external contrast adjustment circuit. The backlight seems to run on normal +5V running into A (+) and K (gnd)...but I can’t figure out where pin A is supposed to be from the pinout in the datasheet. I’m guessing the LCD itself doesn’t have any more helpful labels or anything, just pins 1 and 16 marked probably?   edit: I think the backlight power is connected internally somewhere, as opposed to needing a separate supply.
  9. Starting MB6582 build

    My issue was that the entire cable was connected backwards at the LCD end. I still got some functionality because both sides (pins 1&2 and 15&16) are power (one side for the actual LCD and one side for the backlight) so everything was in fact receiving power, but nothing else was connected correctly. I am pretty sure this isn’t your issue. Looking over your display’s data sheet (specifically the pinout), it seems like maybe your display needs a negative voltage reference for the backlight to function? This issue is described in the LCD troubleshooting document (http://www.midibox.org/dokuwiki/doku.php?id=troubleshooting_lcd_displays) but unfortunately the solution is not described there: it only gives a dead link. :/
  10. Starting MB6582 build

    Hm, I vaguely recall being confused by the pin numbering as well. In any case, the guide you linked to should be correct, as J15 has the same pinout on MB6582 as it does on a normal core (where the pins aren’t labeled, fwiw).
  11. Starting MB6582 build

    I think the backlight should turn on even without a PIC. Is everything else on the board populated? (Thinking specifically about the display trimmers.) The LCD wiring is confusing and was one of my more troublesome spots. I managed to wire it up backwards (or upside down...or something) even after double- and triple-checking my work. Can you do me a favor and post a picture of your wiring and links to whatever documentation you’re working off of? I’m trying to figure out what you mean with the pin numbering (and the more general issue of it not working, of course).
  12. AOUT_NG Eurorack format

    What was the reason for changing to the MAX525?
  13. AOUT_NG Eurorack format

    Did anything ever come of this? I couldn’t find anything else searching... @latigid on?
  14. I made a small batch of custom MB-6582 panels a couple years back. They’re black with white print, have a little “MB•6582” logo on them, and have a trippy graphic behind the mod matrix. I sent out four sets of panels to forum members for their own builds. Just curious if anyone ever got theirs put together. I want to see my babies out in the wild ;)
  15. Starting MB6582 build

    Also: Pictures are working now, looks good! Those filter caps are a little hilariously big, lol. And I love the rainbow knobs on the other synth! Reminds me of the original C64 marketing logos. I wanted to do something similar, but it’s relegated to just the feedback knobs around back.