First x0x, doesn't start up after completing build.

[sackley]

Thread Synopsis: When powering up the kit after completing the build, and having passed all the tests done during the assembly, the LEDs would usually be unlit with the occasional few coming on and remaining static. No sound, no response in any mode, but clearly getting some kind of power.

Solution: The J3 Molex header was on backwards (pin 1 soldered in at the pin 12 position) on the I/O Board.

Thanks again to MMM (aka The x0x Don, aka Sanity Saver)

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Hello all,

First, I just want to say I'm really impressed with the wealth of knowledge and helpful people in these parts - it's extremely refreshing.

So, I built my first x0xb0x (bought the Willzyx kit), but am having trouble after completing the control board. The analog section seems to work fine (I did all the tests during the build, and all worked fine). I soldered FT232 myself (should have paid the $25!) and miraculously it was recognized when plugged into my computer. But, after completing the rest of the kit it doesn't power up as expected.

I get a problem similar to the one here -> http://forums.adafruit.com/viewtopic.php?f=12&t=21219, but my voltages are all over the place! Usually no LEDs are on, but occasionally I'll get a few that stay solid, regardless of what mode the machine is in.

IC3 DC using pin 20 as ground
Pin 9 = -0.14 v
Pin 18, 19 & 40 = 0 v

BA6110 checks out except
pin 6 & 7 = 5.03 v (not 5.3)

I've checked polar component orientation, resistor values, reheated joints, checked for solder bridges, etc... I'm certain there's something I'm not seeing though...
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I'm at a loss, but will not give up! I don't have a lot of electronics knowledge (built a few synthrotek kits and a shruthi-1) but I'm ready to learn and would like to understand why this kit isn't working and how to fix it.

Any help is greatly appreciated! I need a direct dose of acid to my ears ASAP, haha!

[MMM]

Hello all,

IC3 DC using pin 20 as ground
Pin 9 = -0.14 v
Pin 18, 19 & 40 = 0 v

0v on pin 40 means the required 5v for the digital side of the xoxbox are missing, probably completely - or the digital ground connection could be missing. Since you wrote that the computer "sees" the FT232 this means the "digital" 5v are generated (on the IOboard) because this is powered from the same supply rail.
This gives us a bit material to work with. Separate the mainboard from the IOboard. Then measure the voltage on J3 between pin 3 (or 4) and pin 7 (or . You should get the "digital" 5v there. If that works we move on and connect the mainboard and IOboard with the ribbon cable only. Then measure the voltage again - first on the IOboard (same pins) and then on the mainboard (J3, same pins).

[sackley]

Thanks for the reply MMM.

That all checks out (assuming pins 7 & 8 are ground here), both with and without the mainboard connected (just j3, none of the other molex cables connected). 4.9 v all around.

Just to be thorough I did 3-7, 4-7, 3-8 and 4-8 on every test.

Thanks for the help, you're making my day!

[MMM]

Ok, this is looking good.

Doublecheck again if you don't get 5v between pin 20 and 40 of IC3. If you don't get those 5v please check continuity between pin 40 and J3 pin 3/4 and between pin 20 and J3 pin 7/8.

[sackley]

Wow, thanks for the quick reply!

Still 0 v between pin 20 and 40.

There IS continuity between pin 20 and J3 7 and 8.
There IS NOT continuity between pin 40 and J3 3 and 4.

So the +5v is not moving down the pathway (sorry for my novice vocab)? Thank you so much for your help!

Edit: This is also WITHOUT IC3 seated, just the DIP Socket.... is this not the right way to be testing? I was worried about damaging the chip...

[MMM]

So the +5v is not moving down the pathway (sorry for my novice vocab)? Thank you so much for your help!

Edit: This is also WITHOUT IC3 seated, just the DIP Socket.... is this not the right way to be testing? I was worried about damaging the chip...

Yes, it's a good idea to test this without IC3 (although the results should be identical.

So let's trace the 5v rail from J3 and see where there's a break. A magnifying glass is occasionally helpful here.
If you look at the component side of the mainboard you'll notice that the two 5v pins of J3 are bridged together and that the trace then goes from those pins to C102 (on the component side). Check this first - do you have continuity between the two pins on the "+" side of C102?
If you actually have continuity there turn over the mainboard so you look at the soldering side. The 5v are carried through this side along the leg/hole of "+" side of C102. It's actually quite easy to see - it's a thick trace that connects C102, C103, pin 40 of IC3, pin 8 of IC2, S19 and some more. Check if there is continuity between the component side and the soldering side; and if you still don't have continuity between J3 and pin 40 check out this particular trace.

[sackley]

Argh, I realized I was making a newb mistake - reading the DIP pin numbers incorrectly (inverted the right side...).

So, actually IC3 pin 40 = -0.43 v (yes, negative, black probe on pin 20).

I tested for continuity as much as I could, but can't figure out the issue - but there is definitely no continuity between J3 +5 v (points 5 & 6) and IC3 pin 40 (top right )

I worked my way through the path as far as I can figure out; all of the LEDs and their resistors are receiving power, but none of the switches seem to pass the continuity test. I reheated all the pads, but still no dice.

Been probing for the last 1 1/2 hours, trying to find the break in the pathway....

Thanks MMM!! I know this will work out!

[MMM]

Since I don't know if this is just a typing mistake or something else:

but there is definitely no continuity between J3 +5 v (points 5 & 6) and IC3 pin 40 (top right )

5v is not at point 5/6; it's at 3/4... And I'm not sure if I follow the "top right" description; this depends on the orientation of the PCB.

I worked my way through the path as far as I can figure out; all of the LEDs and their resistors are receiving power, but none of the switches seem to pass the continuity test.

OK, let's do this one step at a time. Clip your black probe to the metal tab of the 7805 on the IOboard. We're measuring on the component side of the mainboard. Put it so that the processor (or its socket) is in the right lower corner. Now check the voltages at

- positive side of C102
- IC2 pin 8 (that's the one closest to C102
- IC3 pin 40 (that's the one closest to C102 and C101)

Just to be on the safe side: Turn off xoxbox, put meter into continuity mode and check IC3, pin 20 (that's the one closest to XTL1); the black probe should still be connected to the metal tab of the 7805.

[sackley]

"Top right" with respect to the IC itself - according to the DIP Chip Wiki page... Sorry for the mistake!

This is really challenging me, I thought I had a clue, but now I'm just confused, hah. I'm just going to give the readings I got...

C102 = 4.42v
IC2 Pin 8 = 4.41v
IC3 pin 40 = 4.41v (!)

And the continuity test between the 7805 and IC3 pin 20 Failed!

Just wanted to double check the following on IC3
9 = 4.4v (!) (was - 0.14v previously)
18 & 19 = 0v

Ok, so now I see why I got such crazy voltages when testing with IC3 pin 20 as ground.... as it's not actually GROUNDED! (At least I'm pretty sure... )

So, I checked continuity as you instructed previously (before I understood how to count ) and there IS continuity between J3 3/4 and IC3 Pin 40 (I was testing pin 21 mistakenly).

I also tested continuity between 7805 and J3, and it passes only on 5 & 6. This will all click for me eventually... I'm starting to make some sense of it, but will wait until later to try to explain my thoughts on the matter...

I thoroughly appreciate this help. Seriously, MMM, you're a BOSS!

[MMM]

Just a very quick check:

Is the cable between IOboard and mainboard "twisted"? I'm mainly asking because of this:

I also tested continuity between 7805 and J3, and it passes only on 5 & 6.

Either you're counting this wrong or the cable is twisted (and hence probably one of the headers mounted 180 degrees).

On the mainboard pin 1 of J3 is on the "inner" side, pin 12 is closest to XTL1 (or the corner of the PCB). On the IOboard it's more or less the same - pin 1 points inward and pin 12 is closest to the corner. The connection must be straight from pin 1 to pin 1 and so on.

I'm stressing this because pin 5 and 6 carry the MIDI signal and certainly should NOT have continuity to the metal tab of the 7805 (which is ground). On the other hand, if one somehow thinks pin 12 is actually pin 1 it would make sense (because then the alleged pins 5 and 6 would be actually 7 and 8 - which ARE ground). But unfortunately the same would also happen if the cable was twisted...

[sackley]

About how I feel right now. Had J3 header on the I/O backwards! Will try to desolder and flip it around.

[sackley]

It works!

I just had the J3 molex header turned around the wrong direction on the I/O Board.

Thank you so much MMM! Serious respect.

Edit: How do you send PMs here? If you're in NYC ever MMM get at me and I'll buy you a round!

[MMM]

Very cool! I'm glad that it works now.

If I'm not mistaken it is not possible to send PMs right now (I believe adafruit wanted to make an upgrade to the board system so they turned off PM functionality temporarily).