Aion Electronics Nimbus - no effect

[Marcos - Munky]

The continuity mode is the one with a diode symbol. It'll probably beep when you touch the probes together, and show a value like 0001. It's useful to test if things are shorting together, and we already have symptoms of +9V and gnd being shorted somewhere. The voltage dropping a lot and the battery getting hot shows that's happening.

The 20K indicator means you can measure resistors up to 20K within that range. If you have a 22K resistor, you won't be able to measure it, the multimeter will probably just show a 1 or something like that, and you have to move to 200K range to measure the resistor. You can do the test to check by yourself. Also, why don't just use the 2M range to measure let's say a 1K resistor? The difference is the resolution you'll have. On 2M range, it'll just measure 1K (0.001M). On the 2K range, you'll get a more precise value, useful for circuits that you need a very precise resistor (don't worry on that for guitar circuits).

Looking at your photos again, I can notice something. Your +9V wire is soldered in a ugly and exposed way. You should correct it to be as the other 4 wires near the switch side of the board. I mean, the wire should go thru the hole, and the insulation should be touching the board. I can't be more clear than that, since english is not my main language. It may not be related to the issue (or may be), while you correct it, do another test: disconnect the wire from the board, power the circuit and measure the voltage directly to this wire. Red probe to the wire, black probe to ground (which can be any ground point, like the ground connection of the switch, the nut of the jack or any point of the enclosure itself.

[ajhuff]

Ahh. I thought that setting was for measuring diodes. Gotcha!

I will fix that wire so it isn't sticking up high. But make sure I understand, remove the wire connecting the DC jack to the board at +9V. Then put the red test lead on the wire end and the black test lead on GND? So the jack will not be connected to the board at 9V? Correct?

[Marcos - Munky]

This setting does measure diodes, but also measures continuity between two points (very helpful to check if two thinks are connected together and to find unwanted shorts) and way low resistence (some circuits uses resistors like 0.1r or even smaller than that).

And yes. Remove the wire from the board. Then do the usual procedure to be sure the dc jack isn't touching the enclosure, power the circuit and measure the voltage with the red probe on the wire and the black probe on gnd. It may be a shot in the dark, but by doing this we can check if the short is on the board or on the wiring.

Also, I have something else on mind, that may be related to this last test. Could you take a photo that shows how you're wiring the dc jack?

[ajhuff]

Thanks for teaching me.

Here's the jack that I soldered back up outside of the case so it doesn't touch. The battery is a little spent now, 8.28 volts. With the red test lead of the red wire and touching black to GND I get 8.28 volts. Actually -8.28.volts. I don't know if the negative is important.

[Marcos - Munky]

Well...

Actually -8.28.volts. I don't know if the negative is important.

That's what I was suspecting on the last post! You wired the dc jack the wrong way, with positive connected to the center instead of negative. Even with the dc jack not touching the enclosure, you're shorting the battery wires. D3 is wired as a reverse polarity protection. If you use the correct polarity, it won't conduct, and the current will flow to the circuit. If you reverse the polarity (what is happening), it will conduct and send the current to ground, so it doesn't damage the circuit.

So let's fix your build. Reverse those two wires, with ground (the green one) soldered to the center. Remember you're still using a metal jack, so it can't touch the enclosure. Remove all the ICs again. Power the circuit, measure voltage between +9V and gnd pads. It should be +9V (I will just round up the number).

If it's +9V, turn off the power, put IC3 back, power it on again. With black probe on gnd, measure pins 4 and 8 of any other IC socket. It should be -9V and +9V. If yes, turn off the power again, put the ICs on their sockets, plug your guitar, turn power on again, and hopefully you'll have a working pedal to play with.

[ajhuff]

I had no idea! That was another instruction I had to guess on.

Now I get +9 volts between +9V and GND!!!

But on socket pins number 4 and 8 on both of the empty sockets for IC1 and IC2 I get +4.8V and -4.8V

[ajhuff]

Specifically, negative voltage on 4 and positive voltage on 8 on both sockets. I am numbering them like this.

1 • 8
2   7
3   6
4   5

I googled that. Hope it's right.

[Marcos - Munky]

Ok, so we solved part of the problem. Good news.

On the voltage, yes, negative voltage on pin 4 and positive on pin 8. Your pinout is correct. But there should be 9V, not 4.8. While it will work with those voltages, let's check what's happening.

Check the voltages on both sides of D4 and D5. Also, check the voltage where R20 and R21 are connected together. You've already used that point to check resistence.

[ajhuff]

I'm sorry for being so basic, but when you say check the voltage on both sides of the diode, where do I put my test leads? From the +9V to each side of the diode? Or from the diode to the GND? Or a test lead on each side of the diode?

-AJ

[Marcos - Munky]

Black probe on gnd. You'll often see people posting voltages or asking for them, they're almost always with the black probe connected to gnd.

[ajhuff]

For D4 the voltage is 4.85 on the the non-stripe side, 4.3 on the stripe side.
For D5 the voltage is -4.1 on the non-stripe side, -4.3 on the stripe side.
For R20/R21 the voltage is 2.4.

-AJ

[Marcos - Munky]

Your voltages are technically right. Taking D4 voltage as the "main voltage", voltage on D5 should be around the same but negative, while voltage on R20/R21 should be about half.

The strange thing is the non-stripe side of D4 is directly connected to the +9V pad, so you coudn't have different voltages on those places.

Check those 3 voltages again, just to be sure: voltage for +9V pad, voltage for non-stripe side of D4 and voltage for the battery measured directly at the battery, unplugged from the circuit. They should be the same.

[ajhuff]

Fresh battery for best case. Battery voltage is 9.26.
From +9V to GND is 9.25 volts.
Form non-stripe side of D4 to GND is 5.42 volts.

-AJ

[Marcos - Munky]

That's really strange. Maybe something is wrong in the documentation?

Let's try another two things:
-First, check continuity between +9V pad and the non-stripe side of D4. You don't need power for this one. If there's no continuity, reflow the solder joint (melt the solder joing again and add just a little bit of solder), then test it again.
-Then, if you got continuity, remove IC3, power the circuit and check the voltage on the non-stripe side of D4.

[ajhuff]

The meter reads 1.74 between +9V pad and the non-stripe side of D4. Does that mean continuity?

[Marcos - Munky]

Does it beep when you do this test? Does it beep if you touch the probes together? We should figure out how your multimeter reacts to continuity first, before doing the test. My bad on that.

After you figure how your multimeter reacts when both probes are touching, check for continuity between +9V pad and those stuff: non strip side of D4, strip side of D3, the other terminal of R20 (not the one you used before, that's connected to R21). You don't need power to check them. It may looks like a few random tests, but that's how I can try to find out what's happening on the power input part of your board without having it on hands.

[ajhuff]

I got it! Yes it beeps. I was  not on the +9V pad. So I have continuity to D4, D3, and R20. With IC3 out I have 9.25 volts at D4! I may have been on the LED pad next to the +9V pad before. Sorry. 

[Marcos - Munky]

Don't worry, it happens. Then, if it beeps, everything seems to be fine with the board.

So we isolated the problem to the voltage inverter (IC3) part of the circuit. Check again if C16 and C17 are correctly oriented. I've checked the other ones.

Power the pedal without the ICs. Measure voltage on +9V pad and both sides of the diode. They should be very similar. Then turn off the power, put IC3 back (just IC3) and measure those same voltages again.

If there's a big difference between those voltages, and the caps are correctly oriented, then there is something wrong happening when you're putting the IC. So, if that happens, turn off the power, then check the continuity between every pin of IC3 with it on the board. With one probe on pin 1, put the probe on each other pins. Then move the fixed probe to pin 2 and test all the other pins. Let me know which pair beeps (1 and 8 should beep).

[ajhuff]

Oh, I forgot. I went back and tested the 4 and 8 pins on the empty sockets like you asked up above, now I get full voltage!

-AJ

[ajhuff]

I'm getting close to full voltage on the diodes with IC3 plugged in.