xoxshop.de no sound (UPDATE)

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acidbuzz123
 
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xoxshop.de no sound (UPDATE)

Post by acidbuzz123 »

hy,
i made a short video to show you the knob behavior of my xoxbox.
https://www.youtube.com/watch?v=-eQ3tad ... e=youtu.be
i wrote also this topic: http://forums.adafruit.com/viewtopic.php?f=12&t=53421
i have checkt again the wiring of my xoxbox and then i got sound. but the sequenzer and the led´s are still not working.
hopefully anybody can help me!!!
greez
Last edited by acidbuzz123 on Sat Jul 26, 2014 12:28 pm, edited 3 times in total.

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antto
 
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Re: xoxshop.de strange sound no less

Post by antto »

it's a little bit hard to tell, but... the sinewave that is audible - that's the filter self-oscillating (which shouldn't be happening unless you modified it explicitly)

does the sinewave go away when you bring the resonance all the way down?

as for the firmware.. check if the cpu (the big 40-leg IC) is oriented properly

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antto
 
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Re: xoxshop.de strange sound no less

Post by antto »

and check if it has 5V on pin40 (that's the corner pin, near C101)

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acidbuzz123
 
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Re: xoxshop.de strange sound no less

Post by acidbuzz123 »

hy thx for your reply!
yes the sine wave goes away when i bring down the resonance. that also happens when i bring down the accent.
sorry for my noob question, but how i measure the 5v on pin40? between wich legs? the corner pin to ground?
yes ic3 looks good (the ic is oriented like its printed on the board)

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acidbuzz123
 
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Re: xoxshop.de strange sound no less

Post by acidbuzz123 »

is it possible that a damaged 74AC595 ic chip (ic 8) is responsible for my problem?
i ordered one of this chips separately from the xoxshop.de because the forgot one chip (ic4-8) at my kit, but the post crushed the letter that all legs of the ic chip were a damaged. the legs weren't broken so i put them back in shape.

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antto
 
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Re: xoxshop.de strange sound no less

Post by antto »

the ground on the multimeter should go to a ground point on the x0x, for example at the top metal part of the 5V regulator (where the heatsink is) that's usually easy place to put the probe
the other probe goes to wherever you're measuring (thus pin40 on the cpu)
set the multimeter to VDC mode

as for IC8... that chip is responsible for controling 8 of the LEDs
it's connected to those 8 LEDs, and also to the cpu and to ground/5V
so it could be affecting the other stuff (or not) depending on how much it's "damaged"
if it just "doesn't work" then it wouldn't stop the cpu from working, only those 8 LEDs won't function properly

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acidbuzz123
 
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Re: xoxshop.de strange sound no less

Post by acidbuzz123 »

ah ok i see. i just checked the 5v on pin 40 but i don't get any voltages. :(

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acidbuzz123
 
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Re: xoxshop.de strange sound no less

Post by acidbuzz123 »

a pic how i measure pin 40 to ground
Attachments
DSC_0174.JPG
DSC_0174.JPG (783.71 KiB) Viewed 2454 times

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antto
 
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Re: xoxshop.de strange sound no less

Post by antto »

to make sure the measurement itself is good - check the voltages at J4 (on the side towards the mainboard) and see if you can properly measure 12V and 5.333V on the two sides
if you can, then you're measuring properly

and back to the 5V issue:
measure at the 5V regulator (at the pin which connects with C6) if you get proper 5V there

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acidbuzz123
 
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Re: xoxshop.de strange sound no less

Post by acidbuzz123 »

yes i get 11,85V and 5,31V at J4. but i don't get voltage between ground and pin 40 on the cpu.
when i measure between the 3 voltage regulator pins i get only 0,08V between leg 1(near c6) and 3 and 2 and 3.

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antto
 
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Re: xoxshop.de strange sound no less

Post by antto »

ooh, that's not right then
i also had trouble with the 5V regulator from the kit, it was getting hot and not outputing proper voltage, so i had to remove it and buy a new one (easy to find in local electronic components shop)

so hm...
try doing the tests/measurements that are shown in the build manual http://ladyada.net/make/x0xb0x/fab/powersupply.html
those specifically after the 4 diodes and two capacitors are soldered (C3 and C5)
see if you get "sane" voltages there

if i were you, i'd probably desolder the 5V regulator and test it with a 9V battery whether it gives 5V then (mine didn't)

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mmm
 
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Re: xoxshop.de strange sound no less

Post by mmm »

There's also the chance that there's a short on the IOboard (possibly a problem with the USB chip).

If you're getting the correct voltages at J4 the unregulated side of the power supply probably works. You could also check if you get +6V at J5.

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acidbuzz123
 
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Re: xoxshop.de strange sound no less

Post by acidbuzz123 »

hey guys!
i don't think that there are shorts on the usb chip, because it was soldered in when i got the kit.
i checked j5 and got 5,97 V and 3,50 V.
i did the measurement on the PSU (from manual) and got these voltages:
c3,c5 - 12,7 V and 13,05 V
5v voltage regulator - 12,54V
c1 - 5,97 V
ic 23 - 5,04 V (poti is fully opened)

is there a problem with the poti because the manual says the voltages should be trimmed to 5,33 V ?
should i buy a new 5v voltage regulator?

big thx for your help!!!

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acidbuzz123
 
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Re: xoxshop.de no sound, sequenzer not working, pls help!!!

Post by acidbuzz123 »

i changed the 7805 voltage regulator and now the led`s work!! the voltages of the psu seems right.
its possible to switch the modes of xoxbox but i still have no sound. i can't hear any sound in keyboard mode and when i press start in random mode, the led`s don`t start running.

can anybody tell me what i should do next?

thx for the help
cheers!

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antto
 
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Re: xoxshop.de no sound (UPDATE)

Post by antto »

so, sequencer works? leds blink, buttons respond, start/stop responds?

to test why there's no sound, the usual procedure is:
follow the audio signal from the oscillator, thru the filter, to the vca and mixer, to the output, see where it vanishes
ideally this is done with a scope, but if you don't have one - you can use the "inexpensive headphones" method described in the build manual

so, start by probing at the vco, the waveform switch is a good place to probe, you can see if you got saw and square there

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