No sound/oscillation at VCO

Discuss x0x construction and related issues

Moderators: altitude, adafruit_support_bill, adafruit, phono, hamburgers

Please be positive and constructive with your questions and comments.
Locked
JunkSoulBrother
 
Posts: 1
Joined: Tue Dec 17, 2013 9:53 am

No sound/oscillation at VCO

Post by JunkSoulBrother »

Hi guys,

I've been reading throught the forum and i've hit a problem that i can't get passed.

So i got a xoxbox from xoxshop.de, im following the ladyada instructions and i've hit a problem at the VCO testing stage. i was hoping someone might be able to shed a bit of light on where i should go from here.

I'm only getting a straight line on the O-scope, that jumps up and down when i touch it off r105.
Now i only have a small bit of experiance using the scope but i have a rough idea how it works and i've tried changing every setting i could think of. When tested with a MM im getting 9.59v which is higher than the 8.5 shown on the instructions.

I've tried testing it with ear buds and i get no sound from r62 with a 3v control voltage at r90.

When tested with the control voltage i get 3v at pin 7 on IC11

I've tried swaping out q24, q25 and q27.

My voltages at IC11 without the control voltage are:

1=3.23--- 5=11.81
2=5.33--- 6=10.42
3=5.33--- 7=10.40
4=0 --- 8=0.02

Can anyone give any suggestion as to what might be going wrong?

Thanks for reading.

XeroX
 
Posts: 1
Joined: Wed Sep 16, 2009 4:29 pm

Re: No sound/oscillation at VCO

Post by XeroX »

Hi guys,
I have the same problem like JunkSoulBrother !
So i got a xoxbox from xoxshop.de, im following the ladyada instructions and i've hit a problem at the VCO testing stage. i was hoping someone might be able to shed a bit of light on where i should go from here.
The same for me !
Now i only have a small bit of experiance using the scope but i have a rough idea how it works and i've tried changing every setting i could think of. When tested with a MM im getting 9.59v which is higher than the 8.5 shown on the instructions.
When tested with a MM I'm getting 5,57 V
I've tried testing it with ear buds and i get no sound from r62 with a 3v control voltage at r90.
The same !
When tested with the control voltage i get 3v at pin 7 on IC11
The same !

My voltages at IC11 without the control voltage are:

1=4.55--- 5=1.18
2=5.33--- 6=10.46
3=5.33--- 7=10.46
4 = 0 --- 8=11.80

My voltages at IC11 WITH the control voltage are:

1=4.66--- 5=2.99
2=5.33--- 6=2.99
3=5.33--- 7=2.99
4 = 0 --- 8=11.80

I hope someone has a good advice ;)

User avatar
antto
 
Posts: 1636
Joined: Thu Apr 15, 2010 3:21 pm

Re: No sound/oscillation at VCO

Post by antto »

try the "headphone probe" test (mentioned in the build manual) and see if you can hear the vco tone then
other than that, check all components for proper values and orientation

Locked
Please be positive and constructive with your questions and comments.

Return to “Making x0x”