weird pot situtation.

[MRE]

"Huston, we officially have a WTF?!?! situation up here.."

[thetimboroni]

:-\ not too glad to hear that.  bummer.

[thetimboroni]

hello again.  i know it's been a couple weeks but i've been out of town and working at the Master's Tournament.

I finally got a chance to try out Smash's "touch test" today and here's the results:

....all 8 function as they should.  Meaning - grounded = no random events.  open = random events ("jitters" as Smash says)

edit: i also checked the ground from the gameport to the core.  Change in voltage is .001 so that doesn't seem to be the problem either.

[stryd_one]

Everything seems fine then... If you solder the pots on one-by-one and test them, while leaving all the other inputs grounded, you should find that all is well.

[MRE]

Test after eachpot.  You will find "the wall" where it all goes kaput (IF it goes).

[dj3nk]

where it all goes kaput /quote] Sounds pretty german ? ^^

[thetimboroni]

Test after eachpot.  You will find "the wall" where it all goes kaput (IF it goes).

"Test" what? for what?

As of now I'm still only able to use A5 and A6 but all 8 of them work (as in...all the A5's and all the A6's work fine... but nothing else)

[stryd_one]

OK so:

No pots = Everything is OK

Add one pot, leave all other AINs grounded.

Turn on the box.

Test that there is still no jitter, and that the pot works as expected

Repeat until it doesn't work

Tell us when that is :)

[thetimboroni]

let the tedious project begin!

[MRE]

Based on Timboronies experiences, I have narrowed down the laws governing MIDIbox construction to one of two possible maxims:

1: Being that thetimboroni is a nexus for MIDIbox gremlens, for his own good, he should be barred from building any future MIDIBoxes  :'(

              pooor pooor tim

2: Being that thetimboroni is a nexus for MIDIbox gremlens, for OUR own good, he should be made to build at least 4 MIDIboxes a year, containing all gremlens within his own box, and thus assuring all other MIDIbox builders will have a troublefree and joyous construction.  ???

              pooor pooor tim

[DavidBanner]

MRE you are cruel!!

Cruel, but very funny!

Hang in the there Timboroni you'll get there son!!

[thetimboroni]

http://despair.com/problems.html

haha.  at least my troubles are helping someone right?

[thetimboroni]

well i've tried all the pots now... still can't get anything but A5 and A6 to work.  this really doesn't make any sense.  it's boggling my mind.

[stryd_one]

Sorry... fixed my post because you already answered that.

Basically, all of MRE's advice still applies. One thing that I would try, is swapping around two of the ABC lines between the PIC and AIN boards... That will give us a hint.

[thetimboroni]

Stryd - nothing happens when I switch the ABC lines.

However, after rewiring the whole thing I now have A0, A3, A5, and A6 working.  If you recall, earlier I had A1, A2, A5, and A6 working.... so while the same number of pots work... this indeed progress in that I have something new responding!

[stryd_one]

Nothing happens? How do you mean?

This is becoming clear that it's a wiring issue....

[MRE]

yah..  Id like to see the results of an ohm test between a common ground or 5 volt point and each pot input pin on the chips.  Do this with power off and the chips out.

you need to divide and conquer.  test at each pot input pin on the chip socket and sweep the pot.  You should get a nice 0-10K ohm (or whatever rated pot you have) sweep for each one.

Alternatively you can do it with power on, with the chips out. In such a case, measure between the chip input for the pot and ground, and measure VOLTS.. not ohms.. it should respond to the pot from 0-5 volts.