Circuitbenders Forum
Circuitbenders Forum => BENDING TIPS => Circuitbending discussion => Repair advice & questions. => Topic started by: nochtanseenspecht on September 16, 2009, 01:06:45 PM
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just got one broken.. it is a v1.0
knobs don't work, previous owner said it had to do with with the power supply.
i have another powersupply wich is good.
on the regulators i messure 4,8V, so that should be fine. i allready changed the caps at the power inlet.
the midi to dinsync works, so thats nice, and also i can trigger the notes with my keyboard.
only cant edit them. could it be a software problem ? i noticed the little window on 1 of the eeproms wasn't
completely covered.. would that matter ? any help would be apreciated !! ;D
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Are you sure that the power supply is correct? It may need to be an *AC* supply for the internal power supply to work properly. Get a pic of the board around the power socket and regulators, and I'll see if I can work out what's what.
Other than that, you'll probably find the knobs are selected by... a 4051 multiplexer. Guess what? It's probably dead.
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thanks Gordon !
i will take a look at it + pics later on, i just closed it up again.it hangs between its new friends and does its job for now :)
exept for the knobs, everything works fine, even the switches for conga, toms etc function..
i'm about to test how it respond to cc's.. if i can shape the sounds that way i can live with it i guess..
at least it's a very cheap midi-sync converter so far. and the 808/909 sounds are tasty..
but if i open her up again i will check for the 4051 multiplexer.. just hope it is not smd, like the rest :(
could i just swap it for a new one you think ?i see it's a very cheap component :D
anyway thanks a lot for your help ! i have now an idea where to search for the problem
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well, all parameters respond to midi cc, so that's nice.. think i go play with it for a while before i open it up again
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Did you get the unit working ok?
Just curious as I am having a problem with my power supply (different unit altogether) but am interested in voltage regulators and power rails (seems the first step to check in any unit!).
8)
Cheers,
Nate
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no, but for me it is ok.
i remember i checked for a 4051, wich wasn't there
their factory psu are known to be weak, first try another adapter with more mA
if that doesn't help, measure the regulator output
good luck !
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ok she broke again >:(
seems to be a faulty smd condensator or either one of the regulators.. but thats ok
anyway i checked what ICs are inside, and apart from the opamps and DA converters
i found :
HC138 (2x)
HC574 (5x)
ADSP2181 (1x big square IC)
i hope Gordon reads this :) ; could any of these ICs have something to do with the problem mentioned in the first post ?
Cheers David
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Check the rails derived from the power supply, and see if the outputs from the pots seem sane. Any chance of a couple of decently high-res pics of the board?
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hey thanks Gordon, i fixed it some time ago, the non functioning knob problem still exist,
but all works fine over midi. i guess i just live with it, it is not my main drummachine anyway