Foxx Tone Machine build on breadboard. Something popped, but what?

[Hemmel]

Can you locate the point(s) with low supply voltage on 1^st post schematic..??

I have removed the circuit from the breadboard so I can't do that (don't remember).

However, I have tried other circuits and the behavior stays the same.
Here's basically what I built for my breadboard:
http://beavisaudio.com/beavisboard/img/BB_Main_600.jpg

If I probe the voltage on the "gnd" and "V+" on the Hammond enclosure, I get 9,7V from my power supply. But as soon as I put anything on the breadboard, for example 2 10k resistors to create a voltage divider, then the same probes at the same place show 1,8V !
I don't understand where the voltage goes...

[antonis]

I don't understand where the voltage goes...

Usually where current goes..

More seriously: What's the kind of power supply used (battery, wall-wart or whatever..)??

[Hemmel]

Wall-wart. I could try with a battery, see if the behavior is the same...

[antonis]

Wall-wart. I could try with a battery, see if the behavior is the same...

As long as wall-wart supply is rated at 100mA (or higher), you don't have to try a battery..

Could you apply a 1k (or so) resistor directly across supply (+) and (-), without any other load, and measure the voltage..??

[Hemmel]

Could you apply a 1k (or so) resistor directly across supply (+) and (-), without any other load, and measure the voltage..??

I'll try that this weekend.
Everything is weird since that pop with the Foxx Tone Machine build.

[duck_arse]

please to post a photo or two of your breadboard setup - board, and all wires jack pots switches hanging off it.

[Hemmel]

please to post a photo or two of your breadboard setup - board, and all wires jack pots switches hanging off it.

I will.

[Hemmel]

So.
I totally forgot to take pictures this weekend.
But I thought the issue has solved itself, apparently not.

When there's nothing on the breadboard, it's fine, I get about 9.8 Volts on the V+ and gnd contacts off the Hammond enclosure.
But as soon as I put anything on the breadboard that connects 9+ and gnd, the power supply goes down to about 1.3V.

For example, if I put a NE5532, and connect pin 8 to 9+ and pin 4 to gnd, then the power supply goes down to 1.3V. Removing either pin makes the power supply go back up to 9.8 Volts.
Same with a voltage divider, if I put a 10K from 9+ to a point, and from that point another 10K to gnd, then the power supply goes back down to 1.3V.

The only thing that does not seem to affect the power supply is a cap. I have a 0.1uF cap connected between 9+ and gnd, supply is still 9.8V.

[antonis]

The only thing that does not seem to affect the power supply is a cap. I have a 0.1uF cap connected between 9+ and gnd, supply is still 9.8V.

Thank God..

[Hemmel]

The only thing that does not seem to affect the power supply is a cap. I have a 0.1uF cap connected between 9+ and gnd, supply is still 9.8V.

Thank God..

I know, right?
But unfortunately I don't want to make circuits out of only caps. I'd like to find the reason why my power supply goes down to 1.3V whenever I plug anything like resistors or ICs...

[antonis]

We've discuss about it formerly, didn't we..?? 

There is ONLY ONE reason for a power supply to kneel down its output voltage and it's TOO  MUCH current..

Taking into account the fact that a less than 400μA current (9 - 1.3 / 20k) does that, I'd suggest you to search for any possible short on breadboard connections..


P.S.
It isn't only duck_arse waiting for breadboard wiring pictures, you know..

[PRR]

....I'd like to find the reason why my power supply goes down to 1.3V whenever I plug anything like resistors or ICs...

ALL resistors? ANY resistor? Or only small ones like 100 Ohms, not large ones like 1Meg?

[Hemmel]

....I'd like to find the reason why my power supply goes down to 1.3V whenever I plug anything like resistors or ICs...

ALL resistors? ANY resistor? Or only small ones like 100 Ohms, not large ones like 1Meg?

Yes, ALL resistors. As soon as it connects 9+ to ground. I've tried from 1K to 1M, different values.

[Hemmel]

Well, I'm sorry I forgot to take pictures again.
But I found the problem: the Voltage Sag pot. It was burnt.

Replaced it, everything's A-OK now.

Thanks to all who have replied.

[antonis]

But I found the problem: the Voltage Sag pot. It was burnt.
Replaced it, everything's A-OK now.

Voltage sag pot can't be burnt by mistakenly placing D3 to +9V instead of GND..

What is the resistance and power rating value of your pot..??

[Hemmel]

B10K, unsure of the power rating.
I'm using a 9V 500mA wall adaptor.

[antonis]

If so, pot must been set at about 2% to be burnt..

Anyway, could you plz post a schematic of your particular pot wiring..??

[duck_arse]

if that clipping diode you connected to supply instead of some audio point didn't burn out, it might well have pulled enough current throo your sag pot to burn it - if it had been on a low resistance setting at the time. that's my theory and I'm sticking to it.

[antonis]

OP clearly stated:

But when it came time to plug in D3, I mistakenly plugged it into +9V instead of ground.

I can't see any DC path to GND when D3 is connected to +9V, dispite its orientation..



What I'm trying to do is to draw OP attention for some other cause of voltage sag pot burnt out..

[duck_arse]

OP clearly stated:

But when it came time to plug in D3, I mistakenly plugged it into +9V instead of ground.

I think the key word here is mistakenly. if one end was already plugged to ground, and the "instead of ground" was replaced with "instead of that string of DC isolated parts in front the tone control", then when that diode was other end plugged to a sag-potted supply it would be a valid pot-fritzing DC path maker. but you know me, I never argue.