Problem with 10 step sequencer

Ohmu · Joined: Jul 30, 2009 Posts: 11 Location: France

Hi! I have just finished my 10 step sequencer from mfos, but i have a little problem with the explanation : how to do 12v ou 15v with one or more 9v battery. On mfos website nothing explain how to power the sequencer. Does anyone can help me? Thank !

skylab76 · Joined: Dec 30, 2007 Posts: 38 Location: Austin

Hi Ohmu ,

Take a look at :

http://electro-music.com/forum/viewtopic.php?highlight=battery&t=33836

It mentions how to set up +/- 9V from 2 9V batteries based on a suggested configuration from soundlab.

OR you can wire 2 of these the same way using AA batteries to make +/- 12V. I did that for a while until I got 12 V PSU.

I hope this helps.

Regards

spitfire · Joined: Jan 06, 2011 Posts: 18 Location: Lithuania

Hi everyone. First message for me in this forum. I happy to be a new user here, I think there's about two people in my country doing analog things, so this forum is heaven Smile

I made MFOS 10step sequencer, everything works fine, accept little problem with third step, it doesn't work at all, giving nothing at CV output. I checked many times, don't see that wires are not connected or smth. I also changed the tranzistor 2N3904, still doesn't work. I connected it as a first step and LED flashes, and I can control CV output with trimmer.

Can it be that CD4017 chip broke at only one pinout inside ? I don't think so.

I hope I wrote clear.

Thanks.

-minus- · Joined: Oct 26, 2008 Posts: 782 Audio files: 13

You might want to swap that 4017 for a new one. Did you use IC sockets? Makes it easier when chips need replacing. If you still have the same problem you need to look at the wiring coming from the step 3 pin which is PIN 7 on the 4017 I believe.

If the transistor will function with a different step activating it, then there is a problem with Pin 7. If you used a socket you might want to check that the legs are all in the socket correctly and pin 7 is not bent (easy to have this happen). Reheat the solder on pin 7 just incase you have a cold solder joint there.

You must be close to having this working. I just looked at that sequencer. It's got a few components! Are you building it on one of the MFOS boards?

Good luck!