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sequenser stops by it self
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sequenser stops by it self

by aminoacid on Mon Oct 25, 2010 7:29 pm

my adafruit xox has been acting bad lately.

i run it as midi slave to my mpc1000.

the sequenser sometimes stops from just tweaking a knob, pushing a button or just taping the panel.

sometimes this accurs more or less...


i recently changed the resistor near the opto isolator to 130ohm thinking that it might been the problem...


it may be some silly lose wire or solder issue. but if anyone recognize the problem i would like to hear. tired of opening this machine all the time and i ve got a gig coming up next month.
my machines kills fascists!
aminoacid
 
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Re: sequenser stops by it self

by Brassteacher on Mon Oct 25, 2010 8:38 pm

aminoacid wrote:my adafruit xox has been acting bad lately.

it may be some silly lose wire or solder issue. but if anyone recognize the problem i would like to hear. tired of opening this machine all the time and i ve got a gig coming up next month.


It is quite likely something loose, or a bad solder joint, or both. The big clue is that you say you're opening it all the time. When you open it, are you tweaking things, adjusting things, etc? If so, check near anything you regularly adjust. Ribbon cable connections often fail at the joints/plugs/header, even when the ribbon is soldered to the board. I just finished rebuilding an old Roland SH-09, and the keyboard cable connector drove me nuts. Every time it was tested with the case open, it tested just fine. Close the case and tap on the faceplate, and it would either go crazy or stop playing all together. I finally had to ditch the connector and solder the cable directly to the board.

When you put it back together, does the case go back together easily? If there's some resistance, check all the solder joints in the area of the machine where the most resistance is felt. Big question: Does it happen all the time, or only after the machine warms up a bit? If it doesn't do it when cold, check everything near the heatsink. If that's all good, check for a logic chip that is a lot hotter than all the others. If you find one, swap it with another if possible. If a different chip in that same spot also starts getting hot, you'll need to check everything going into and out of that chip.

Alternately, if one of the buttons is rubbing against the case in such a away that it is partially held down, that could cause the behavior as well.

Another thing to check, watch the inside of the case carefully as you close it up, and see if there is a possibility that two things are making contact, or almost making contact with the case closed. The way the resistors fit on the board, assuming you used 1/4 Watt resistors this is a real possibility. Also make sure nothing such as a resistor lead, or any bare metal inside the case is making contact with the bare metal on the very top of an electrolytic capacitor. On most capacitors, that metal shell is connected to the negative lead (That's why they're shrink-wrapped). On anything I work on/build that has tight spaces near the top on an electrolytic cap, I always cut a small square of electrical tape to cover the exposed spot.
Don Taylor, a.k.a. Brassteacher
"Jack of all trades, master of none, proficient at even fewer..."
Brassteacher
 
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Re: sequenser stops by it self

by aminoacid on Tue Oct 26, 2010 7:05 am

i think your in the right area.

ill try replacing all home made flats with better once.

thanks for the help!
my machines kills fascists!
aminoacid
 
Posts: 341
Joined: Tue Jun 20, 2006 5:27 am
Location: acidburg