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x0xi0 IO & Overdrive - Install & Troubleshooting
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by kroutshev on Sun Mar 15, 2009 8:55 pm

Hi Brian,
Thanks for your quick answer.

1. Sound output is low:
How quite is it? is it about 3dB quiter than normal or is much lower? it's very much lower !!
What is value R155? it's 100 K like in manual.
In this post
Phono had same problem and spoken about "J7" but where is "J7" ?

2. Distortion doesn't work. i've made a mistake when type is down i have sound but type up no sound ... it's overdrive which is failed ....
After remove far left L-bracket i've got the same problem, i've checked pcb and circuit isn't cut.

1) The signal is coming in good at pad B =>
i have 0V and on mainboard J7 pin 1 = 0 V. Pin 2 and 3 = 0 V
On J4 it's ok 5.33 V and 12 V.

3. Headphone output is mono.
Yes you're right i have installed Accent out circuit.

Thanks.
kroutshev
 
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by bcbox on Sun Mar 15, 2009 9:32 pm

1. You may have a bad solder joint somewhere along the way. Here's what to do to find out what section has gone bad...
a) take the signal from the VCO Out jack and send it straight to your mixer. This is the output of the VCO. Chances are it's good good and loud.
b) take the signal from the VCF Out jack and send it straight to your mixer. See if the output is still good level.
c) If it still sounds good and loud then the problem is after the VCA. If you have an oscilloscope check the signal at pin 3 of the volume pot. With the volume turned all the way up it should be greater than 2V peak to peak.
d) If you think all is good up to this point the problem could be a bad conection from J7 pin1 on the x0xb0x mainbard to Pad B on the x0xi0 board, or from Pad A on the x0xi0 board to J7 pin 1 on the x0xb0x I/O board.

I noticed in your comments you mentioned the signal is good at pad B on teh x0xi0 board but 0V at J7 pin 1 o the x0xb0 mainboard? The signal from J7 pin 1 on teh x0xb0x mainboard goes to Pad B so something is not right there. Make sure thsoe connections are correct.

2. Overdrive doesn't work. You may have seen the comments already but I'm pasting these from Alex's post from a few months earlier..
a) The signal is coming in good at pad B (since distortion works). Check it there and see what you get. With x0xb0x volume turned mostly up it should be greater than 2V peak to peak. If you're just using earbuds to test you'll hear it.
b) Test it again at pin 1 of SW302. This is before distortion so should sound same as 1). If OK go to step 3)
c) Test it again at IC301 pin 1. It should now be distorted depending on setting of Amount pot. If ok,
d) Test it again at IC301 pin 7. It should sound nice and overdriven, adn quite loud. If ok,
e) Test at SW302 pin 4

see at what point you lose signal.
bcbox
 
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by kroutshev on Mon Mar 16, 2009 4:50 am

Sorry Brian, i'm not very clear, i think i've lost my brain into x0x pcb ...

The main problem is there's no signal on J7 on mainboard. I have copy previous Alex's post and that's why you see "1) The signal is coming in good at pad B =>" but it's not true in my case.
I have begun to make these tests and i have 0V on J7 of the mainboard Pin1, Pin2 and 3.
That's why it's normal that overdrive doesn't work there's no sgnal to PadB obviously. I think it's not a problem from x0xio board but into my mainboard and near J7. Because in troubleshooting post Phono had same problem with low output and problem with J7. I think that i have the same problem between low output and overdrive failed.
I'll try with VCO and VCF jack out tonight !!
Thanks.
kroutshev
 
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by kroutshev on Mon Mar 16, 2009 5:31 pm

Ok Brian about mix out, from vco jack out i've got good level but vcf jack out is wrong, volume is very low.
kroutshev
 
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by bcbox on Mon Mar 16, 2009 7:59 pm

ok, I see, you just built the whole x0xb0x with the mod so you don't know exactly where it's gone bad.
Since you have the VCO up and running I would test the VCF next. Do the tests as shown in the x0xb0x build manual and see if you get the correct waveforms (do you have an oscilloscope?). When doing these tests you won't apply 3V to R90 because your x0xb0x is already asembled. Instead you simply put the x0xb0x in keyboard mode and play the high C note.

There are some posts in the Making x0x forum that tell you what the voltages are at various points in the VCF section. This helps tremendously in finding problems. See if you can find those posts, then you can just use your multimeter and probe around. It seems to me you probably have a bad connection somewhere.
bcbox
 
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by kroutshev on Tue Mar 17, 2009 4:12 am

Yes you're right i already built x0x and mod, i'll test vcf section tonight.
Thanks.
kroutshev
 
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by bcbox on Tue Mar 17, 2009 4:29 pm

here's the thread I was referring to for testing the VCF...
viewtopic.php?t=3619
bcbox
 
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by kroutshev on Tue Mar 17, 2009 8:51 pm

Ok Brian i have measured vcf section and try to see where is the problem.
Q21 seems to doesn't have right measure, i have cheked resistors values and they are good ! Do you see others things which could be wrong ?

R62
6.64+6.58

C27
2.45+11.37

R111
1.89v +11.90v

Q21
2.45v+1.89v+1.83v+1.89v+2.45v

R110
1.90v +11.91v

R113
2.45 +3.73

R112
2.40v +3.73

R109
2.40+0

Q20
1.75+ 1.83 +2.40

R108
1.76v + 0

C25
11.37+2.45

R114
3.73+2.45

C29
3.73+0

Q19
1.31+11.90+1.90

R96
0v+1.31v

R116
3.74+5.34v

R97
5.33+5.33

C23
5.33 +4.34

Q18
4.34+11.92+4.87

R94
0+4.34

R99
4.87+5.10

C22
5.10+0

R66
5.34+5.10

Q10
3932+3.32+3.30

R68
5.34+5.33

R72
3.30 +3.27

Q12
5.33+9.61+4.75+9.60+5.33

Q22
11.38+11.92+11.90+11.93+11.38

R62
6.64+6.58

Thanks.
ps : i havn't got oscilloscope ...
kroutshev
 
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by kroutshev on Wed Mar 18, 2009 7:01 am

i've opened a new post in making x0xb0x section about my vcf problem. After resolve this do you think that distorsion will work better ?
Thanks.
kroutshev
 
Posts: 146
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by bcbox on Thu Mar 19, 2009 3:14 am

I see your post in the other section. Good idea because Guest is great at helping debug the x0x. Be patient and take it section by section and you will get to the bottom of it. Once you get the VCF working properly then you can verify the VCA is working. Then once you know everything is working up to the point where the signal is sent to the x0xi0 distortion you'll be able to test it. You probably just have one or two minor problems.
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by kroutshev on Thu Mar 19, 2009 4:21 am

Yes Brian i think too.
Thanks for your help.
kroutshev
 
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by kroutshev on Tue Mar 24, 2009 8:57 pm

Hi Brian,
i have resolved my low volume problem. It was R109 and R112 which had bad values, i have changed them for resonnance boosting but not as given in manual.
I have soldered 10 K resistors and my x0x have good volume now.

But overdrive still doesn't work. I have checked J7 and no signal ...
I will check schematics that you have sent me !

Thanks.
kroutshev
 
Posts: 146
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by bcbox on Wed Mar 25, 2009 3:10 am

I'm glad you're making progress, it takes a lot of patience.
Let me know what you find when you probe the overdrive circuit.
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by kroutshev on Thu Mar 26, 2009 2:44 am

The thing that i don't understand that if there's no signal on J7, overdrive can't work ? the problem is before x0xi0 ? i have to look before J7 mainboard, isn't it ?
Thank you Brian.
kroutshev
 
Posts: 146
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by bcbox on Thu Mar 26, 2009 4:15 am

if you don't have signal at pin 1 of J7 then you shouldn't have sound at the main output of the x0xbox. Whether or not the overdrive/distotion circuit is working at this point is irrelevant.
For piece of mind you could do a quick test by hooking up J7 back to stock x0xb0x specs. Simply hook the wires from the x0xb0x mainboard to the x0xb0x I/O board as shown in teh x0xb0x build manual when buildinga stock box. This effectively bypasses the x0xi0 distortion/overdrive circuit. See if you have output.
bcbox
 
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Please be positive and constructive with your questions and comments.