129 is assembled..needs some serious troubleshooting

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Fallenstar
 
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Joined: Wed Nov 09, 2005 3:07 am

129 is assembled..needs some serious troubleshooting

Post by Fallenstar »

Well I get no sound. I get stuff happening on headphones when I listen at the waveform switch. It is almost like circuit bending though as I can get different tones based on where I ground the headphones.
I also have a problem with the note keys. The top row of notes (Sharps) do not light up or change the state of any light on the lower part of the keyboard. All the other buttons seem to work. Also when i cycle through the steps in the sequencer when I hit step 8 it stays dark, when I move it to 9 it gets very very bright and the 9 never lights all others work properly. Any help is very appreciated. I thought I did a careful job assembling, the only thing I messed up was switching two pots, but I fixed that.
Thanks for any advice.

Jonnay
 
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Post by Jonnay »

Sounds like a problem with the LEDs. My guess is that some of the resistors are shorting out. Especially Number 8 and 9.

Fallenstar
 
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Joined: Wed Nov 09, 2005 3:07 am

Post by Fallenstar »

Thanks I found the 2 resistors contacting problem. As for the other issues, I am getting no sound yet. The sharps keys still do not do anything in any mode. In random only the tempo led lights up, and no other led seems to switch on when buttons are pressed, is this normal? Also what is the machine supposed to do in user mode? All mine does is dimly flash the tempo led. I am trying to get this little box working, and I am rapidly getting frustrated. Any help is very much appreciated.
Bobby

Jonnay
 
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Post by Jonnay »

User mode doesn't do anything unless you download or compile your own firmware.

Given that you had problems with the LED resistors in the sequencer section, the first thing I would do is check out the resistors in the VCO (R74-R90). Make sure there are no shorts there, it gets pretty tight.

Test the VCO again, just so you are sure it works. After that, I think the next thing to do is to start testing the following: Your VCF, the gate, and the VCA... probably in that order. Testing the VCF with headphones is similar to testing at the waveform switch, you're just probing a different connection. Just put the thing in keyboard mode, and keep hitting C.

There are all kinds of directions on how to test the envelope and the gate signal on the board. Just browse the last 10 threads or so. (one day I'll go back and post those directions to the wiki...)

djarago
 
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Joined: Sun Jul 10, 2005 1:45 am

Post by djarago »

sounds similar to what's happening on my system. I recall if you hold down chain or r/b or some key other than a note key while pressing a # key the light will come on. i also suspect that the mcu pin controlling my gate is bad.

I initially thought something with my LEDs were bad, but considering the lights turn on if you do this funky thing I just think that it's a problem with the firmware.

jelle
 

Post by jelle »

hey,

did any of you solve this problem? i'm testing my vco and it's not stable, but like circuit bending indeed. changing pitch all the time, although if i come close to the board it's starts to really freak out. I can modify the pitch using vr/tm5(/tm4)

any tips are welcome

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subatomic
 
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Post by subatomic »

jelle wrote:hey,

did any of you solve this problem? i'm testing my vco and it's not stable, but like circuit bending indeed. changing pitch all the time, although if i come close to the board it's starts to really freak out. I can modify the pitch using vr/tm5(/tm4)

any tips are welcome
Is your x0x finished, or still building? If you haven't started the digital section yet, there's a floating (unknown voltage affected by the air and static elec) voltage controlling the VCO pitch. If you put a voltage to the VCO's pitch input (i.e. 2V or 3V) as described in the fab manual, then that will "clamp" the pitch down and keep it there.

wires
 
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Joined: Wed Nov 30, 2005 1:22 am

Post by wires »

hi, sorry (i thought i send a message, because:) I figured out what was wrong, indeed, a floating voltage. I didn't connect the ground of my 2.0v PSU to the ground of the x0xb0x psu; that seemed to be the problem.

thanks a lot!

Fallenstar
 
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Joined: Wed Nov 09, 2005 3:07 am

Post by Fallenstar »

I fixed mine. The defective chip was the cause.

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