Predictive* digital music synthesizer (Pandora's Box #2)

Step 10 ORIGINAL PANDORA'S BOX CIRCUIT

This one has been struck twice by anomalies, and now is in an unbelievable condition.
One difference: I used a 1.842000 crystal.

UPDATE: ***It has just been found that there is an error in this schematic,
and pins 9 and 10 (upper right pair) are reverse connected on both 4040's. ***

Comments

[VIRON]

Check to see that the pin 11 resets (gray wires) on 4040's are to "ground". If not then they will stop and glitch randomly and intermittently. It also sounds like time to try putting bypass capacitors (0.1uF) on V+ and ground of the chips. When they roll over 1111 to 0000 that is when they are most needed since they may glitch then. Also, make sure the "blue wire" on pin 1 of the right 4040 is clocking pin 10 of the left 4040. We found an error in the schematic of the uC-less pbox before you reversed pins 9 and 10 on 4040's so that should be already fixed now. Also, using the amp or piezo or an LED, look for pure tones and ticking noises and blinking on 4040 pins that have diodes. (Some will be unhearable, so just make sure that some are making constant tones or ticking sounds. These get mixed in all combinations by the diodes to make the melody but they should be steady and stable coming out of the 4040s)

[VIRON]

First try reversing pins 9 and 10 connections on both 4040's. (the two upper right ones). Don't worry about the capacitors; tell me if this made a difference.

[gregor]

WAHOU :-)) IT work...ed.! just about one minute, and after a beautiful pitch down, silence... I changed the battery, checked the diodes i just resoldered... Counting backwards?

[VIRON]

It only goes forwards. As a fractal, it may seem repetitive. There should be a neverending melody that even includes inaudible ultrasonic tones but it should not go silent, it should keep a beat indefinitely. The battery should last days or weeks.

[gregor]

hi, i read that you ommited ('bypass' ??) the capacitors on the 4040... does it matter here ? Or should I , as every one tells, add a 100 uf on each chip, in parallel with power pins? -I'm trying to make it work but can't find what's wrong in my board...