#2000 Megadrone

That’s because it uses a white PCB with black silkscreen, so everything is reversed…

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At JLCPCB two of the options are black solder mask
ardumuse
and white solder mask
ardumuse2

You see the problem. The - side is the “filled” side, but whether that’s black or white depends on the solder mask and silkscreen colors, and it’s easy to get it wrong if you’re going by the “white”/“black” section and not paying enough attention.

There’s a + sign here which is unambiguous. Go by that. Also the + solder pad is square, but that could vary between footprint designs. (And as discussed here not too long ago, for LEDs the standard KiCad footprint has the square pad for the - side, confusingly.)

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Oh, duh! I didn’t even clock that. Thank you. I was too focussed on the caps. That makes sense.

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This makes sense. Thank you! Though now I am going to have to go and double check my LEDs as well…

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My first build is the Megadrone and I’ve got some problems…

Powering via 12v power supply. When I power up I’m only getting sound from one of the oscillators, the rest aren’t making any noise. Only about half of the led’s light up ( yes all in the right way ).

Any suggestions where to start troubleshooting ? Suggestions gratefully received :slight_smile:

Welcome aboard!

Two quick things to try first - the wiki for ‘general troubleshooting’ (link below) and also your power supply; what are you using?

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Hi, thanks for the reply.

I’m using a 12 volt power supply via barrel jack and not euro. I’ve reflowed any obvious cold joints.
Bizarrely I’ve discovered if I bridge the legs of R37 all leds light up, and it seems to work, except for the master volume ???

OK… but this is a regulated/smoothed power supply as opposed to one directly from a ‘Wall Wart’ type DC adaptor? Just wanted to check, as if it’s not then fluctuations in the DC may cause weird issues.

Yes it’s a wall wart supply. I’ll have to get hold of a euro power of some kind and try it with that.

I’ve just finished building the mega drone and I have done some troubleshooting. I’m using a variable output power supply with +/- 12v, there are no dry joints and the components are all correct. I can get all the leds to light up and I can hear the output on a small speaker, but it’s very quiet. All the controls do what they are supposed to do.
When I plug the module into my case with a eurorack power source everything still lights up but I don’t hear any sound.
Any suggestions to what might be causing this?

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Baws. Everything was going so smoothly too. I had socketed the MOSFETs, but turns out the sockets were too thin for the legs. I couldn’t cut them down reliably, so ended up removing the sockets and soldering the MOSFETs on directly. However, in doing so, I managed to lift a pad on one of them. I’ve soldered some wires from the other side of the PCB and fed them through the whole which I’ll connect to the MOSFET… but now I have a horrible suspicion something will go wrong later. Ah well, at least I’ll know where to begin troubleshooting.

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odd! is the wire that connects from the board to the jack the right way roundhabve you tried swapping the wires?

but not low enough to be inaudible so it may still be an issue I think

good luck! you never know sometimes there is a pleasant surprise haha

try swapping the mosfet!I had a whole batch that were not working, so yeah this is a mosfet problem did you solve it?

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not yet, but yeah it’s probably the mosfet…

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Finished mine last weekend and finally plugged it in and took a video last night. I used blue LEDs and added 10 rotary switches so each oscillator can be set to one of 6 capacitor values: 47uf, 22uf, 10if, 4.7uf, 2.2uf, or 1uf.

Here’s a video! It’s too dark to see the extra switches (because I make spooky music I am only allowed to jam in darkness) but I assure you they are just to the right of the Megadrone.

Here’s a picture of the capacitor selectors! These switches are cheap garbage, don’t use them, two of them broke just putting the knobs on.

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Nice drone ! welcome in the forum

btw it’s LMNC not LMNK :wink:

The switches look like the ones Tayda sells, they don’t inspire a lot of confidence but I haven’t actually broken one yet.

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