x0xi0 Full Kit - Install & Troubleshooting

[bcbox]

ok, so CV looks good but no VCO2 waveform (VR405).

Does VCO2 work (tested at VR406)?

1) Check the VCO1 saw output on the x0xb0x mainboard. This would be the junction of R105/R35/C10/Q28. If ok go to next step.
2) Check the VCO1 square output on the x0xb0x mainboard? This would be Q8/R36. If ok go to next step.
3) Check the VCO1 saw output at Pad 3 on the x0xi0 Top PCB.
4) Check the VCO1 square output again at Pad 2 on the x0xi0 Top PCB.
5) Put SW401 (VCO1 waveform) in the up position to select saw. Check the resistance between Pad 3 on the x0xi0 Top PCB and Pin 3 of VR405. It should be 0 ohms, since with the switch in the up position the saw waveform coming in at Pad 3 goes directly to VR405.

[tupinamba]

1) Check the VCO1 saw output on the x0xb0x mainboard. This would be the junction of R105/R35/C10/Q28.

NOTHING unless xmod knob is up.

2) Check the VCO1 square output on the x0xb0x mainboard? This would be Q8/R36.

Same thing

3) Check the VCO1 saw output at Pad 3 on the x0xi0 Top PCB.

Same thing

4) Check the VCO1 square output again at Pad 2 on the x0xi0 Top PCB.

Same thing

5) Put SW401 (VCO1 waveform) in the up position to select saw. Check the resistance between Pad 3 on the x0xi0 Top PCB and Pin 3 of VR405. It should be 0 ohms, since with the switch in the up position the saw waveform coming in at Pad 3 goes directly to VR405.

OK : no resistance between pad 3 and right leg of VR405.

And still : cannot play tunes on the keyboard : I only get something when in pattern mode. What I get (with xmode on) is kinda weird but, hey, that must be xmod...

I'm as lost as before : why nothing on the original board unless I turn xmod up on the new board ?...

[bcbox]

1) ok, the fact that Xmod gives output makes me think that VCO2 works.
This makes sense as the (bad) signal from VCO1 can still be modulated by VCO2 when using Xmod.
Does the saw and square both work for VCO2? This is important, since it will eliminate a lot of testing if VCO2 works.

2) Keyboard mode not working is strange, did it ever work? Aside from replacing or reprogramming the microcontroller you can double check all the connections and component values from the microcontroller to S3 & S4. This includes D3-D10, S3, S4 connections, R254, R255, & Q5. Double check values of the resistors, orientation of the diodes, and continuity of the traces between all parts.

3) There's something going on with VCO1.
a) Double check the CV at Pad 13 on the x0xi0 Top PCB. It should be 2V when playing back note C1.
b) Make sure D402 on the x0xi0 Top PCB is placed in the correct direction.
c) Make sure TM4 is a 50K trimpot and TM5 is a 5K trimpot (these are on the x0xi0 Top PCB - the row of four trimpots..)
d) Check 12V supply voltages local to to VCO1.
- IC11 pin8
- R103
- Q27 emitter
- Q28 drain
- R45

use the pic in this thread showing reference voltages, this will help determine which is the correct side/pin of each component to test:
http://imageshack.us/f/836/mainboardwithanaloguevo.png/

e) Check 5.33V supply voltages local to VCO1.
- IC11 pin3
- Q26 pin1
- R101
- R36
- R100/R101

f) if everything is ok so far there may be a bad component somewhere. Use the reference voltages in the pic linked above to check every node in the VCO1 circuit.

[tupinamba]

Thanks for your answer Brian, lots of testings to do tomorrow !
For now, the only thing I can tell you is this : Keyboard mode used to work great before I started the mod so I guess I did something wrong... More important : I switched to SOKKOS and installed the microcontroller you sent me and this does not change the keyboard mode issue.
I can still program bass lines in pattern mode, which means that keys are responding...
I'll tell you more tomorrow. Now it's bed time here in Paris

[tupinamba]

[UPDATED 2011-01-21]

Tests performed :

First of all, one good news : I found what was going on with keyboard mode. There was a small piece of lead shortcuting on the mode selector. Keyboard mode works fine now !

1) I don't know if VCO2 works... I get something on VR406 (VCO2 level) only when XMOD switch is on "1-2". And I only get sound on VR405 (VCO1 level) when XMOD switch is on "2-1" (and of course when XMOD volume is up a bit, in both cases. When XMOD to minimum, no sound at all, neither on VR405 & 406, nor on the x0xb0x mainboards you asked me to test earlier for VCO1).
Saw and Square switch (VCO1) makes a difference in sound on VR405 (still with XMOD switch on "2-1" and level up). Same for the VCO2 waveform switch with VR406.

2) I did not change any component in this area I guess, and it used to work fine... Diodes orientation is fine, traces seem to be OK.

3) When C1 is played...

a) Voltage is RIGHT on pad 13 now... as I adjusted TM404 . The note produced changes when I turn the XMOD knob (I guess this makes sense : the further clockwise, the higher in pitch)

b) OK : all diodes are right on the x0xI0 Top PCB, including D402. D404 is not filled.

c) TM5 seems to be 5k (reads 4.7k when completely on one side). Hard to test TM4 as I think other components are interfering. I get a 6K when power is down, but I guess this isn't relevant. However TM4 and 5 do change the tuning when I play with them.

d) OK : all those voltages (IC11 pin8, R103, Q27 emitter, Q28 drain, R45) are 11.88V

e) OK : all those voltages (IC11 pin3, Q26 pin1, R101, R36, R100A & B) are 5.33V

f) I found out that I removed C51 on the x0xb0x mainboard whereas it seems to be meant to stay... Could this be the source of my trouble ?...

Here are two pictures of the x0xb0xI0 board and the x0xb0x mainboard, just in case something obvious wound catch your eye...

http://lostchild.free.fr/img/x0xb0xI0-board-1.jpg


http://lostchild.free.fr/img/x0xb0xI0-board-2.jpg

[tupinamba]

So...
I decided to go back a little and remove the x0xI0 top PCB and try it with only the I0 and Mixer boards.

--> I put missing components back (not the ones that have to be removed for I0 and Mixer boards) and remade missing connections (IC12 pin 4)

--> I put back C51 that I think I removed by mistake because I just saw it missing on the guide's picture.

--> I realized there was a confusion about wires for the mixer PCB power supply and switched the red and yellow wires so as to get 5.33v on pad 6 and 12v on pad 9 of the Mixer board instead of the contrary (I noticed by looking at the mixer PCB install guide instead of the Complete kit install guide v2.0).

At this stage, I still didn't get anything through the rear outputs...

... But I got LFO1 right when probing the LFO section of the mainboard...

[EDIT 2011-01-22]
I get the signal right up to R62... But as R62 and C17 have been removed, what next?... No signal on the other side of the removed resistor... If the distortion circuit on the I/O board is supposed to send something, it doesn't, although I rechecked all connections from I/O board to x0xb0x mainboard.

[EDIT 2011-01-23]
I put back R62 and C17 and my x0xb0x came back to life... This means that the mixer PCB is correctly wired and that's a great thing. This also means that there's something wrong with the distortion circuit.

Is there something missing in the manual? I double checked all the wires between x0xb0x mainboard and x0xI0 I/O board before trying to but R32 and C17 back on the board...

What I really don't get is how the sound signal is supposed to get out of the VCO section despite the removed R62-C17, as nothing is sent from R62 to the IO board... So LFO1 doesn't go anywhere, and it makes sense I was unable to get it on the x0xI0 top PCB...

Here is an image of the x0xI0 I/O board, there may be something obvious to an expert eye...
(as for the pictures above, you can click on the link to get a bigger picture).

http://lostchild.free.fr/img/x0xi0-IO.jpg

[tupinamba]

OK, we're getting closer...

I removed R62 and C17, connected pad S of x0xi0 IO board to C17 (-) and pad T of x0xi0 IO board to R62, and it seems that it works pretty good : nice sound through Phone output and Line output, and the Filter and Distortion sections of the IO work great.
I had the hint about connecting pad T to R62 by reading Altitude's post :
http://forums.adafruit.com/viewtopic.php?f=13&t=7224&p=65058&hilit=tips+x0xI0#p65058

So :
1) Is there something missing in the IO install guide ? Because it says to connect pad T of IO PCB to pad T of Top PCB... But people who get the IO kit alone do not have a Top PCB to connect it to!
2) If I reinstall the Top PCB and connect pad T of IO PCB to pad T of Top PCB, what do I connect to R62 so as my VCO1 doesn't go nowhere ?

[Blackout1234]

man looking at your I/O board up close it is full of probs with your soldering.

as i mentioned in my points in the other thread, the I/O board is a double-sided board with separate tracks on each side, doing different circuits. Actually its one of the most brilliant circuit board designs by Brian ...its a beautiful thing. But you basicially dont have enough solder on a lot of your components, eg R345. you can see in the pic clearly the ends of the resistors are going in through the holes and not even touching the pad point on the component side.

i experienced this with the distortion switches not getting enough solder on either side at their terminals and basically i heard nothing out of my whole kit. until i poured solder down along all the switch legs down onto the pads on the component side as well as soldering from the base side. Then my x0xi0 came to life

maybe you were soldering the board too quick or with the wrong temp and not letting the solder properly draw through along component legs until they hit the other side...but i would do a complete re-touch of solder points with some more lead if i was you for starters. i think this is your big prob.....

cheers,
Blackout

[tupinamba]

Hi,
Thanks Blackout!
I checked the solder joints on the component side and apparently it was OK (testing continuity between the leg of component and terminal). However, I put more solder on a few ones, just to be shure.
I'm now resoldering the x0xI0 top PCB to the other boards. I figured out how VCO1 ges to the x0xI0 top PCB : pads 2 and 3, connected to S1 (waveform from VCO1, just before R62 on the mainboard tracks!)
I'll post later to tell how things went... Fingers crossed!

[tupinamba]

Back to NOWHERE...
1) I removed the components that I had soldered back on the board (S1, R61 _ jumpered _ , D35, R123)
2) I remade connections from IO PCB and Mainboard to Top PCB.
3) We're back to where we were before I removed the Top PCB :

With XMOD to min., playing a pattern :
--> Nothing on VR405 or 406
--> Nothing on pads 2 & 3 (connected to former S1 switch pad 1 & 3)
--> Nothing on VCO section on the mainboard (tested at Q26, R36, R105)

With XMOD a bit up, playing a pattern... Well, I get sound everywhere, but it sounds like XMOD : a bit weird and cheesy, with the pitch depending on how much I turn the XMOD knob.

I'm starting to feel a bit depressed. I've spent days on my free time trying to troubleshoot and I'm still stuck where I was 3 weeks ago...
I'm thinking of leaving the Top PCB aside and just using the IO board, which yet offers great possibilities.

Here are, just in case, last hope, two large pictures of the board, on both sides. I tried to tidy the wires the best I could for the board to be as clear as possible. (the 2 wires disconnected from the main jumper on x0xb0x original IO board where connected when I tested the board...)

http://lostchild.free.fr/img/x0xi0-top-view.jpg

http://lostchild.free.fr/img/x0xb0x-rear-view.jpg

[tupinamba]

This is a sad day for s0xb0xing...

I removed the Top PCB, replaced components needed like the first time... Except that this time not a single sound comes out of the s0xb0x. Nothing on R105 or R36. Nothing on ANY transistor of the VCO section, despite a digital section that works fine and 2-3v OK on R107.

I think that's the end for me. I quit. Too much time, too much trouble, too much disappointment.

I thought that after building a s0xb0x, a Midibox MB6582, a Midibox MB-SEQ and several smaller projects I could handle this. That's the proof that I can't. I even managed to destroy it completely.

This is a sad day for s0xb0xing...

[tupinamba]

Well...
Two days after this really bluesy mood things are a little better. I figured out why I had no sound at all (forgot to reconnect IC12 pin 8 to pad Z of the x0xi0 IO board).
But still I'm feeling completely discouraged about the x0xi0 Top PCB and I think I'll leave it this way, with just the IO board.

One last thing that bugs me a bit is the noisy attack that seems stronger than it used to be. Something like a clipping noise...

[tupinamba]

The x0xb0x works fine with the IO kit installed, back in its case. I used it live a week ago and everything ran smoothly. I'm really happy with the distortion mod, really powerful. I still have to experiment with the ins and outs though...
Still feeling "a bit" frustrated with the Top PCB not working but I'll get over it eventually!

[Blackout1234]

my suggestion is to order another X0xi0 mod kit and build. then once its working then go back to this troublesome board and start comaparing piece by piece until you find the problem.

[xjn]

Hi all,

I'm having trouble with my full kit install. I have everything completed but all I'm getting out of the outputs are clicky thumpy sounds like a gate opening and closing. The leds for hi-res and hi-range flash along with the white led when those switches are activated (which I don't remember happening the last time I built one of these) I've double checked all the flying wires and IC, transistor, and diode placements and found a couple errors (one soldered to wrong leg of resistor, one error switching pad 9 and 6 on the mixer PCB, ouch) but the problem seems to be that there is no 12v coming from IO board to power the top PCB on line D. I double checked everything I could around that area, nothing stands out. The IC measures around ~25v on the input and ~1.6v on the output. I have a couple extra lm317s around I could swap in there and that's all I can think to do now..

Any ideas?

I'm also missing the gate pushbutton momentary DPDT switch, does anybody have an extra I can buy off them?

Thanks!