x0xi0 IO & Overdrive - Install & Troubleshooting

[charlie_says]

Thanks BC.
Another quick question: I'm presuming that the 100 trimpot is the one labeled p101 and the 20k trimpot is the one labeled p203?

[bcbox]

yes.

[kartoshka]

hi Brian and other fella xoxers!

i am having problems with overdrive circuit.
everything else seems working (i did not test it throroughtly 3.5 jacks), main switches/pots/buttons work and f.

when type switch activated up, i'm having no sound at all.
when switch is down, distortion works smoothly and sounds sa-ha-weet!
i hear sound both in headphones and main out, unprocessed and processed respectively as explained earlier.
Overdrive outputs silence.

rechecked it triple-twice to watch for soldering faults, bad joints, etc. none found.
pls help!

[bcbox]

I think I have the schematic here on my mac... I'm still on vacation. I'll reply again when I have a chance to take a look and give you some things to test. In the meantime, do you have the schematics for the kit?

[kartoshka]

Ah, didn't know you're on vacation!
will keep silence until you return.

regarding schematics, i have only the install/use manuals.
i see the artwork layer is there but no schematics.
hmmm.... and i coudn't find it available on http://www.alphazone1.com/x0xi0/ site, for that matter.

[bcbox]

send me a pm with your email address and I'll email the schematics to you.

This is the order to check things..

1. Make sure you are getting power to right places...
IC303 Pin1 = ~12V
IC303 Pin3 = ~6V (make sure IC303 is in correct orientation)
IC301 Pin8 = ~12V
SW303 Pin2 (SW303/C304) = ~6V

2. Check that you have signal at SW302 Pin1 (SW302/C301)
3. Check for signal at IC301 Pin1
4. Check for signal at IC301 Pin7
5. Check for signal at SW302 Pin4 (SW302/R325)

With the x0xb0x volume all the way up the signal should be greater than 2V peak to peak (regardless of the setting of the overdrive amount control). If you don't have an oscilloscope try using earbuds as described in the x0xb0x build manual.

[kartoshka]

pm sent

[kartoshka]

Ok,
i (hopefully) identified the prob.

it's in the amount pot.
it's somewhat failing (it didn't work before, i did not touch soldering iron at all - it just began to function, absolutely spontaneously).

Listen to test-recorded file.
http://believe.mytinydream.com/x0xIO-38/overdrive-amount-pot-failing.mp3

first i play the sequence with xoxio on, type (up on) overdrive, tone and amount all the way down.
then i turn tone up, full way up.
then, i touch amount and turn it all the way up too, later playing with it.
then both of the controls go down - to their initial state.

second, i switch the type (down to) distortion, and execute same procedural cycle.
tone to full on, then amount up to full and playing with both.
then, both controls go back down again.

third, i turn xoxio module off and hear xoxbox naked.
no xoxbox controls were touched during the recording.

So, amount pot needs to be replaced.
I can't find it locally (local ratshack refuses to stock ANY dual pots, been in this story before - with effects pedals for synths)

thanks for the schematics, any case,
email sent again.

[bcbox]

The pots are dual gang and the overdrive and distortion circuits are completely independent. One section of each pot is for the overdrive circuit and other section is for the distortion circuit, so it's possible for the distortion circuit to work and the overdrive to be faulty as you describe.

[kartoshka]

first i play the sequence with xoxio on, type (up on) overdrive, tone and amount all the way down.
then i turn tone up, full way up.
then, i touch amount and turn it all the way up too, later playing with it.
then both of the controls go down - to their initial state.

second, i switch the type (down to) distortion, and execute same procedural cycle.
tone to full on, then amount up to full and playing with both.
then, both controls go back down again.

third, i turn xoxio module off and hear xoxbox naked.
no xoxbox controls were touched during the recording.

fixed!
http://believe.mytinydream.com/x0xIO-38/amount-pot-fixed.mp3
recorded from cheap mic, otherwise same cycle, same pattern, same bpm.

thank you for prompt help, BC.

[bcbox]

very good news, I'm glad the new pot made it in good shape, I packed it well.
I will update the thread for this issue and call it closed.
Hoewever if yo have any additional questions you can find me hear just about every day.

[alex_dubinsky]

I'm having the following problem: the distortion works fine (type switch down), but the overdrive output is extremely quiet and without the overdrive effect.

[bcbox]

I would first pinpoint where the signal goes bad.

refer to the schematic.
1) 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.
2) Test it again at pin 1 of SW302. This is before distortion so should sound same as 1). If OK go to step 3)
3) Test it again at IC301 pin 1. It should now be distorted depending on setting of Amount pot. If ok,
4) Test it again at IC301 pin 7. It should sound nice and overdriven, adn quite loud. If ok,
5) Test at SW302 pin 4

see at what point you lose signal and go from there.

[kroutshev]

Hi Brian,
i've got some problems after x0xi0 build ... The volume of main output is very low, distorsion doesn't work, no sound and phone output is mono and not stereo.
Overdrive is ok and filter too.
What i have to test please ?
Thanks.

[bcbox]

Hi Bruno,

1. Sound output is low:
How quite is it? is it about 3dB quiter than normal or is much lower?
What is value R155?

2. Distortion doesn't work.
First thing to check is to make sure the L-bracket on the far left is not shorting out the circuit.
If you look at the bottom of the x0xi0 PCB you will see that the screw for the third L-bracket
goes over a PCB trace. This is a design flaw I didn't catch. If the screw is tightened too much it may cut through the soldermask and short out the circuit since the L-bracket is connected to the rear panel, and the rear panel is grounded. Unscrew it and see if this is the case. If so you can insulate it first by adding a plastic or fiber washer underneath the screw, or by putting a piece of electrical tape between teh L-bracket and the rear panel.

3. Headphone output is mono.
Did you install the optional Accent Out circuit? See page 22 of the Install manual for details.
If you did install Accent out it uses the Ring of the headphone output so you'll only get output on the right side of your headphones. The headphone output is mono but the same signal is fed to both sides. If you install the accent out circuit and also want the headphone output to both ears you'll need to make an adapter that feeds the Tip of the headphone jack to both left and right sides of the headphones.