finished! - and beginning troubleshooting

loopcycle · Joined: Nov 06, 2006 Posts: 101 Location: California

im only in the first stage of testing.

1. pattern A leds dont light up whatsoever.
(i will swap cd4034s to determine if this is the cause.)

2. pattern switches and led behavior work opposite as expected (stage 9-16). all leds on 9-16 are LIT when pattern switches are OFF and i manually load.

3. stage 14 led stays constantly lit. (the switch is fine.)

loopcycle · Joined: Nov 06, 2006 Posts: 101 Location: California

answer=1. swapping cd4034s show one does not work. will replace.

answer=2. i assumed (NEVER ASSUME!) that the switch in "closed" position meant bit high. nope--the docs show closed being bit low. stupid me. ah well, at least i didnt label my panel yet Laughing

loopcycle · Joined: Nov 06, 2006 Posts: 101 Location: California

4. have to troubleshoot the glide on channel A (a+b works fine).

5. range not working whatsoever. im a little stumped by this.
i tested the switch before soldering.
im stuck on an augmented fourth (diminished fifth?) interval for any range setting.

State Machine · Posted: Mon Apr 21, 2008 3:54 am Post subject:

Scott Stites · Posted: Mon Apr 21, 2008 7:13 am Post subject:

Hey Loopcycle,

Sorry about the delay - I was gone all weekend camping in the wilds of Eastern Kansas.

Good to see you got a number of your problems solved.

For the Glide problem - does your A+B voltage come through, it's just not gliding? How about your B output - does it glide?

For the range problem: First of all, see if your switch voltages are getting to the CD4051 (U7). The switch voltages go to pins 9, 10, and 11.

With your range switch at the lowest range setting, pins 9, 10, and 11 should all be low (0V or so). That would be an easy enough test right there, actually.

If you want to test all of the ranges, the voltages would go as follows (0 being 0V and 1 being close to the positive rail):

Range Pin 9 (C) Pin 10 (B) Pin 11 (A)

1 0 0 0
2 0 0 1
3 0 1 0
4 0 1 1
5 1 0 0
6 1 0 1
7 1 1 0
8 1 1 1

Now, if these ranges aren't switching, the problem could be either the switch or a bad/reversed diode (IE, one of the switch diodes, D1 through D12). To check to see if it is the switch, you can disconnect the switch from J9 (if you used plugs) and test the switch positions one by one with with a volt meter. You could also visually eye your switch diodes to make sure they all have the cathode in the right spot, and also you could test the diodes themselves.

If things look like they're switching OK at U7, then make sure you have the trimmed voltages going to the inputs of U7 - pins 1, 2, 4, 5, 12, 13, 14, and 15 are the inputs - they should each have a different voltage on them coming from the trimposts. If *that* looks OK (you have different voltage levels on the input pins, and the control pins are switching), you should see the level changing on the ouput of U7, which is pin 3. If that is changing OK, then U7 and your switch and diodes are working correctly, if not, and the levels and switch voltages are OK, you may have a bad CD4051.

Pin 3, the output of U7 CD4051 feeds pin 3 of U6, a TL072 configured as a unity gain buffer. If the input pin 3 of U6 is changing, but the output (pin 1 of U6) is railed or unchanging, the problem would lie there.

In the meantime, try out the above measurements and tell me what you find.

Good luck and take care,
Scott

State Machine · Posted: Mon Apr 21, 2008 7:08 pm Post subject:

loopcycle · Joined: Nov 06, 2006 Posts: 101 Location: California

State Machine · Posted: Wed Apr 23, 2008 7:12 pm Post subject:

loopcycle · Joined: Nov 06, 2006 Posts: 101 Location: California

loopcycle · Joined: Nov 06, 2006 Posts: 101 Location: California

i made a couple videos over here.

http://loopcycle.blogspot.com

(i cant link to the actual post, since the url-title includes the terms "electro-music" and the forums auto-format these terms and break the link. Laughing

)

Sound · Joined: Jun 06, 2006 Posts: 842 Audio files: 1

I like very much the klee-firstImpression2 video! Very Happy

Scott Stites · Posted: Fri Apr 25, 2008 12:58 pm Post subject:

loopcycle · Joined: Nov 06, 2006 Posts: 101 Location: California

Scott Stites · Posted: Sat Jul 26, 2008 12:58 pm Post subject:

OK. Make sure U5 (the 10V regulator) is supplying 10V to the tops of the divider resistors. I suppose checking any of these resistors (R26 through R32) would tell you that right away.

If that looks like it's OK, remove the CD4051 and check the input pins at the socket - if that makes the voltages work, then your CD4051 needs replaced.

If that doesn't work, make sure the bottom of each trimpot is connected to ground.

If all so far fails to provide an answer, let me know what voltage all the inputs to the CD4051 are fixed at.

Good luck!
Scott

loopcycle · Joined: Nov 06, 2006 Posts: 101 Location: California

blue hell · Posted: Sat Jul 26, 2008 5:27 pm Post subject:

Scott Stites · Posted: Sat Jul 26, 2008 6:13 pm Post subject:

Well, don't fret...I'd be lying if I told you I'd never reversed an IC. As many ICs as are in this project just increases the odds of that happening Very Happy

12.78 Volts at ranges 5 and 7 - if you simply turned the CD4051 around, that might still be a bit suspect - it could have taken a hit from its reversal that's making it act oddly.

I suppose, check the output of the CD4051 then trace it through the circuit at those range settings - I bet you'll figure it out.

Take care,
Scott

loopcycle · Joined: Nov 06, 2006 Posts: 101 Location: California

yep, i done blowed up my 4051 by putting it in backwards.
with a new 4051 its working lovely. thanks for all your help scott Very Happy