Muff's Modules & More

Matrix12x · Posted: Thu Jun 21, 2012 6:38 pm Post subject: Oakley VCO rev 4

Hi all,
I recently built a rev 4 of the oakley VCO and everything works except for the Pulse output. All other outputs work great. Any ideas on where to start my search? The schematic shows a connection called "source"that feeds the pulse circuit. Where does this start from? If I understand correctly does this come from the switch and that chooses the tri or saw as the source for the pulse?

Thanks for any help. And for your patience.

decaying.sine · Posted: Thu Jun 21, 2012 7:05 pm Post subject:

Did you check the solder on the signal and ground for the pulse out? That's a good place to start. A cold joint could explain why you get the other waveforms and not the pulse.

If you can snap a really high res pic of the pcb and wiring, some folks might be able to help you troubleshoot. Also Paul and Tony will probably see this before long.

decaying.sine · Posted: Thu Jun 21, 2012 7:08 pm Post subject:

You may consider asking a mod to move this to Music Tech DIY for better troubleshooting visibility. If you need to get Tony or Paul's help you can PM the thread link.

Try PM'ing Luka if you prefer to move the thread.

Synthbuilder · Posted: Fri Jun 22, 2012 2:28 am Post subject:

Please don't PM me. PMs are not really to be used for any commercial communications - and personally I don't like them very much. Yeah, I know, call me old fashioned. E-mail if you have to but I prefer to see building support questions on this forum. This is generally the first port of call for most Oakley builders.

Source is the wiper of the switch that chooses which source the pulse comparator circuit gets its reference from. So the wiper of the switch (the middle pin) should have either a triangle or a sawtooth wave on it. If you have no switch connected, or no signal on the switch wiper, then you're not going to get any pulse output at all.

The source signal comes from pin 1 of the MAIN-2 header. It's shown on page 1 of the schematics. If you want to quickly test the board without fitting a switch you can simply use a thin piece of solid core wire to link out pin 1 and pin 3 of MAIN-2.

Tony

Matrix12x · Posted: Sun Jun 24, 2012 7:06 am Post subject:

Thanks for the replies. I checked the switch and it has signal on all 3 contacts. When probing the switch, When I switch it, the signal switches from triangle to saw when looking at the other pin on the switch. Solder is good on the Pulse output jack.

I am going to probe the header that supplies the pulse out to the jack.

John

Matrix12x · Posted: Tue Jun 26, 2012 10:08 pm Post subject:

Found it. broken trace on back of pcb. I must of broken it while clipping leads.

Thanks for the help. Gave me some good things to look for.

decaying.sine · Posted: Tue Jun 26, 2012 10:28 pm Post subject:

I'm celebrating with you! I love finding the bugs and fixing them! Such a good feeling. Glad you figured it out.