Build Your Own Clone Message Board

sorry if the topic is too much, but the 47ohm resistor glow a bit and then smoke came out straight away....

before that i just had it build 2 days ago and it didnt work and i dont have time to post the pictures to the forum. until this morning i check that again, and the MN3007 chips was not in the slot properly so i push it in a bit and try again. this time the LED led up but not blinking (i used 470 ohm instead of the 4.7k. then the smoke and followed...

should i just replace the 47ohm resistor or is there anything else gone wrong in my pedal? please help.........

sounds like a short somewhere, we're really going to need pics. i definitely wouldn't just put a new resistor in because odds are it'd happen again.

do u need the back of the back as well?

The front looks pretty good. I'm color blind though so I can't tell if all the resistors are in the right places.

What does the under side of the PCB look like? If there's a short on the PCB that's most likely where you'll find it.

_________________
"It’s your soldering."

thanks guys!!!

Your soldering looks a bit suspect. You should have solder joints that look sort of like tiny Hershey kisses. The chip socket's solder joints have a concave look to them like there isn't enough solder. The wires at the bottom edge of the PCB don't look right either. You shouldn't be able to see down into the hole the wire goes into like that.

Take a wire brush to the bottom of the PCB to clean off the solder spatter. In the upper right corner (and a few other spots) I see what looks like a ball of solder on one of the traces.

Lets have a look at the soldering to the jacks and pots too.

_________________
"It’s your soldering."

depth knob


rate knob

about the wire, maybe i used lighter gauge wire than those provided with the kit, so should i put more solder to cover the hole or use the original wire?

sorry this is just my 2nd build, please bear with my silly questions, what is a wire brush? spatter is the shinny thing on the PCB? do u mean the legs need to be shorten?

mate really appreciate for your help!!

The soldering of the pots doesn't look very good either. You should never have blobs of solder like I'm seeing here. Take a look at this photo. There are no stray strands of wire sticking out anywhere or blob of solder on the solder lug. You might want to take a look at my Tips Thread in the DIY Discussion forum to learn more about wire tinning and dressing



The wire gage shouldn't make any difference if the soldering is done well.

A wire brush is just that. A brush with wire bristles. The spatter is the little balls of solder like the one I mentioned above. If you have any excess lead sticking thru the solder joints they need to be cut off down to the solder joint. Leaving the leads sticking thru the PCB is a short circuit risk.

_________________
"It’s your soldering."

Finally have time to get back to my chorus..

i wanna get the 47ohm resister, but how many watts should i get??

From your description, it sounds like there's something seriously wrong with your power supply, did you use a battery or an adapter when this happened? I would go over and redo all the wiring of the power jack and battery.

The 47 ohm resistor is the first thing your power supply sees, if it actually glowed and smoked this probably means you have a serious short from 9V to ground. But it could also mean you've used a power supply with the wrong polarity or voltage.

A 1/4W resistor is what you want here, but you'll have to find and fix the issue before you replace it and power it up... otherwise it will just happen again. And the bad news is, you may have accidentally fried other components too.

K

i was using adapter when it happened.. i had used the same adapter when i tested my shredder and it worked so i think the adpater is fine..

is there any way i can check where the problem is?