x0xb0x no sound except clicking noise

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tanta
 
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Joined: Sun Jun 20, 2010 9:27 am

x0xb0x no sound except clicking noise

Post by tanta »

I've builded a x0xb0x and all I can hear is clicking noise in all mode. I have search relate topics in this forum. Most likely it is the VCO problem. I've done some testing in the VCO part.
1./ I get 5.33V and 11.9V on J4, so the power is ok.
2./ I have checked all caps and resistor value is correct in the VCO part.
3./ I have re-touch every joint with the soldering iron make sure they have good contact.
4./ I have check some DC votage , I get DC 2V and 3V on IC11 pin 7 when I press the middle C and C1 ( I guess this is correct?)
5./ I have check the DC voltage around the VCO area, I don't have correct reading around D25 (junction point on D25 and Q27, junction point of D25 and Q24 Q25). Correct value should be something around 5.7v to 5.88V, but I have 0V on both junction point.
6./ I have replace all D25 , Q27 Q24 Q25 2SC1583, 74HC174 and 4066 with new parts, the problem is still there.
I have no idea what is causing the problem. Please help. Thanks

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mmm
 
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Re: x0xb0x no sound except clicking noise

Post by mmm »

Check if those two junction points have possibly an (unwanted) short to ground. Just measure if there is continuity between them to ground.

tanta
 
Posts: 42
Joined: Sun Jun 20, 2010 9:27 am

Re: x0xb0x no sound except clicking noise

Post by tanta »

No, they are not short to ground. Is there any particular point I should check the DC voltage?
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mmm
 
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Joined: Tue Apr 24, 2012 1:51 am

Re: x0xb0x no sound except clicking noise

Post by mmm »

I'm not home right now and hence can't make any comparisons (so this would have to wait a few days); however you might want to remove Q25 to see if there is any change around D25.

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x-11
 
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Joined: Mon Jan 05, 2009 9:39 pm

Re: x0xb0x no sound except clicking noise

Post by x-11 »

Hi Tanta,

is q22 a 2sc2291
and q21,q12,q26 are 2sc1583
maybe you swapped one accidentialy.
this causes clicking sound and no waveform.

u get saw on headphone test?(see building guide)

greetS

shawnsick
 
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Joined: Sun Mar 09, 2014 5:49 pm

Re: x0xb0x no sound except clicking noise

Post by shawnsick »

Did this problem ever get solved?

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DrHouse
 
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Joined: Sat Dec 30, 2017 1:43 pm

Re: x0xb0x no sound except clicking noise

Post by DrHouse »

This exact same problem with xoxshop kit is driving me crazy, 0v on D25, Q27 junction. Other voltages seems to be quite ok, DC Bias however is 10v and it should be around 8.5v according to build manual, I am using 2x 1.5volt batteries to give me around 3.2v cv.
I have so far only done power, which is ok 11.78v and 5.33v and soldered only VCO parts. Can't heard anything, not even clicking with pair of Sennheiser PX100 (impedance 32 ohm).
I also changed Q27, Q24, Q25 and D25, no change and there seems to be no shorts.
I do not have scope, only multimeter, any suggestion what to check next?

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DrHouse
 
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Re: x0xb0x no sound except clicking noise

Post by DrHouse »

And it works!
I didn't have 2SC1583 but PMP4201 based replacement part and another of it transistors was dead, or SMD part is not correctly soldered (have to check that still).
So if it does not work, it is always fake 2SC1583 or faulty replacement part :P

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