Home › Forums › Altura Theremin MIDI Controller Forum › Altura FAQ & Support › Articulation control not working
Tagged: altura, articulation
- This topic has 10 replies, 2 voices, and was last updated 4 years, 5 months ago by zdlAdmin.
I finally complete the assembly of my Altura! Everything seems ok but the trimmer potentiometer VR8 seems that doesn’t work, I mean..as written at page 45 of the assembly manual, I tried to set the articulation value to 45 but while I screw (or unscrew) the little trim pot, the display doesn’t show any value changing…I checked the installation and it is ok .. any idea? Thanks.
Are you following the “Easter Egg” instruction? Turn unit off, turn all knobs full left, turn back on. First you should see three digits: what are they? After a few seconds the display should change to a number divisible by 15: what is it?
I’m following the “Altura Assembly Manual.pdf” I downloaded from your website.
I switch on the unit, then:
– numbers spinning;
See also the video at this link
The spinning numbers indicate you are in Play mode, not Articulation mode. The “1. 8” indicates the positron of the last two knobs, Octave Near and Octave Far. The 8 tells us that the last knob, Octave Far, is turned to the right, not the left. All knobs must be full left when powered on to enter Articulation Mode.
If you tell me “But the last knob IS full left!”, then I will say “Extraordinary! It is behaving backwards! Turn it until the display shows ‘1. 1’, then power of then on. Now at last you should be in Articulation Mode. “
Well, my Altura seems to be really extraordinary!
In fact, the octave far potentiometer set full left shows 8 .. while full right..8 again!
If I set it at 1 (which it is, of course, in a middle position between full left and full right) then I switch off and on the unit, it doesn’t run in articulation mode 🙁
Aha! You do have an extraordinary unit! That pot is probably bad, or the microcontroller may be poorly seated.
1. Re-seat the microcontroller. Carefully pop it out and seat it back into the socket.
2. Turn on the unit. Gently but firmly press down on the shaft of that fussy pot, and sweep it through its full range. You should see the numbers 1-8 appear smoothly. Your video reveals that the pot does not seem to behave as it should. Another way to verify is this: set Function to 6, X-Y mode. Now the last pot is used to set the MIDI value, 1-127, transmitted when the right sensor senses your hand at the far limit of its range. Turn the knob smoothly without pressing. Do you get a jumble of jerky 1274numbers? Do you get something other than at full left and 127 at full right? Try again while pressing down. The numbers should scroll smoothly across the range.
If these tests are positive, then the pot is bad and must be replaced and we will send you a new one.
Please run the test and let us know!
I re-seated the microcontroller (ATMEGA.. etc…).
Then I switched on the unit.
Nothing has changed..I have to say that pressing the pot does not have a positive effect on the same (see the video).
Well..I am at your disposal for any other test even if it seems the problem is in that pot..let me know!
Ooooops! Hey guys, I finally checked again the soldering of that pot and made it again .. now it works!
Nevertheless..since my Altura is a very special one, it seems to me I can’t get into the articulation mode!
It seems to me “key” pot is not working (check the video) .. any suggestion to test it? Of course I’ve already soldered it again 🙂
Thanks for any suggestion and help!
Hmmm, sneaky. Your KEY pot behaves like it is not connected somewhere. The microcontroller polls the eight knobs and reads their voltage, so many times per second. It maps the voltage onto a table to decide what value is desired. If it reads 0 volts, as when a pot is disconected, it will always display the first value in the table, in this case C. So since the pot seems completely unresponsive, we think there is a broken connection somewhere. Here’s how to check.
1. With the unit off, measure the resistance between the two outer pins of the pot. If it IS properly connected into the circuit, you should read 1.9kOhms. If the pot is NOT properly connected, you will read something higher.
2. If that’s the case, check all the solder connections associated with this pot, including its corresponding pin on the multiplexer.
3. Look also for solder bridges. This is an unintended connection causing a short. A bridge can consist of even a tiny whisp of solder touching two pads together that are not meant to touch. Tiny bridges can be popped off with a little gentle scraping. Larger bridges may require melting and removing the excess solder.
Hey guuuuuuys! I made it!
Finally, I realized I missed some soldering point .. now it works!
Thanks again for the fast and precious support you gave me! I look forward to test the Altura and .. to face the next challenge with a Zeppelin Lab kit!
Congrats! We always believed in you. Moral of the story: check your solder joints veeeeeeeeeeeeeeeeeery carefully.