Help me debug Big Muff Pi Clone, pedal works but enclosure shocks me? Weird.

[Se7en_Costanza]

Hey guys need some help debugging a Big Muff Pi clone a friend gave to me to fix.

It had a few problems with it, like dry solder joints. Ive fixed everything up to how its meant to be visually, but for some reason, the pedals enclosure shocks you when you touch it, all the knobs crackle when you turn them, and there is a faint high pitch oscillation that can be heard when the pedal is on. With a multimeter the Positive and Negative terminals on the power jack are saying that they are connected together like a dead short, but the pedal still works and plays? weird..

Any idea on what to look for here, its an exact big muff clone, so the big muff pi schematic is the one to go off.
and its the generalguitargadgets.com BMP pcb.

Any help is appreciated

[EBK]

This sounds SO much like one of these types of problems:

[EBK]

Could you post some pics (of the board, jacks, and wiring)?

[Se7en_Costanza]

Kind of stumped, on what to do, also all the voltages on the transistors are all about 3 volts higher than they should be.

[EBK]

Have you measured your power supply?

Could you list your transistor voltages?

[GGBB]

With a multimeter the Positive and Negative terminals on the power jack are saying that they are connected together like a dead short

Multimeters don't usually lie.

[EBK]

With a multimeter the Positive and Negative terminals on the power jack are saying that they are connected together like a dead short

Multimeters don't usually lie.

Unless their batteries are dying.

[EBK]

I'm inclined to think that the problem is faulty grounding in the amplifier or power supply (the electrical shock thing can't be caused by this circuit, can it?).

[italianguy63]

I'm inclined to think that the problem is faulty grounding in the amplifier or power supply (the electrical shock thing can't be caused by this circuit, can it?).

I would certainly think not.  Should not feel 9V unless you put your tongue on it.

I'm with you--- must be coming in on the signal cord.

MC

[Govmnt_Lacky]

The crackling and shocking are definite indicators that you are shorting DC power and ground together. The easiest way to TS this would be to disconnect the PWR and GND wires from the PCB and check if the power jack is shorted. If not, then check resistance between power and GND on the PCB. You should get some resistance but nothing less than about 100 or 150 ohms.

Are you only getting the crackling and shocking when the box is closed up? It looks like the PCB might be resting on the indicator LED.

If not, then you definitely need to find out where the DC and GND are shorted. I would not recommend powering it on again until you fix the issue.

[Se7en_Costanza]

Hey guys so it was my power supply being shitty! with a battery across the dc jack terminals its fine, thanks for your help, i thought it was weird i could feel 9v shocking me, doesnt make sense. anyway i got it sorted thank you all for your help

[antonis]

it was my power supply being shitty!
i thought it was weird i could feel 9v shocking me, doesnt make sense.

Include "leaky" to "shitty..