[Mullet]

I'm at the point where I had to put my CMOY project down for a minute to take a deep breath.

I'm at the phase of the project where you test out voltage of your power supply. This is right before you begin putting together the signal section. When I do my voltage test I get around -9 volts. on the negative side of the amp. From Tangents tutorial, I surmised that I have a solder bridge somewhere in my signal flow. My guess would be that the bridge is on the positive side being that I get no voltage reading. I'm attaching a picture that sort of shows where I think the problem lies.

I've tried to desolder the whole area, but I'm having trouble. My solder wick doesn't seem to be picking up any solder. I've used Tangent's desolder tutorial but it's just not happening the way he describes it. Do I need to turn up the heat on my hakko? I guess I could try using my flux pen to see if that helps.

I think the root of this whole problem is I'm probably applying too much solder to my joints. Again I surmise this is due to being a newbie at soldering and electronics.

I'm hoping I can remove C1, the LED, and the 9v battery holder on the positive side without ruining them. If I do have a solder bridge across the 3 holes of the copper pad is that ok? If I have it cross between two pads is that ok? I'm not sure where I'm going wrong here and I want to do this project to almost perfection.

Thanks,
Mullet

 

[nikongod]

Unfortunately the bridge could be in any number of places, but you are right to start at the PS.

Do you have a good strong magnifying lens? I'd go around the board and check out every joint.

 

[nullstring]

EDIT: it should look like this:
http://tangentsoft.net/audio/cmoy-tu...-underside.jpg

protip: you can bridge anything thats already connected by wires or copper
but you can't bridge something thats connected by a capacitor or resistor or chip (or anything but a wire)

 

[ROBSCIX]

I would start with he power input and verify you have power there and keep moving through the circuit verifying power at each step. When you hit a point without power you are at the right place. Trouble shooting circuits can be tedious work but it is good to learn.

 

[Mullet]

Quote:

Originally Posted by nullstring /img/forum/go_quote.gif protip: you can bridge anything thats already connected by wires or copper but you can't bridge something thats connected by a capacitor or resistor or chip (or anything but a wire)

Unfortunately, my work in progress is at work so I can't take a 2nd look until tomorrow. However, my guess is that the the bridge is between the first and second copper pads on the positive side of the circuit.

Quote:

Originally Posted by nikongod /img/forum/go_quote.gif Do you have a good strong magnifying lens? I'd go around the board and check out every joint.

I just have the magnifying lens that comes with my helping hands. I'll probably have to get a loupe of some sort to rectify the situation.

Quote:

Originally Posted by ROBSCIX /img/forum/go_quote.gif I would start with he power input and verify you have power there and keep moving through the circuit verifying power at each step. When you hit a point without power you are at the right place. Trouble shooting circuits can be tedious work but it is good to learn.

I do have power indeed. I have my LED hooked up and when plugging in a 9V battery the light lights up. I'm still pretty sure that I have a bridge somewhere because of the multimeter voltage reading I got. Tomorrow I'll have another go and we'll see what happens.

~Mullet

 

[Pars]

With the black lead of the meter on the virtual ground (the two strips down the center of the board), when you measure V- with the red lead you get -9V? What do you get for V+?

 

[Mullet]

Quote:

Originally Posted by Pars /img/forum/go_quote.gif With the black lead of the meter on the virtual ground (the two strips down the center of the board), when you measure V- with the red lead you get -9V? What do you get for V+?

For V+ I don't get any reading at all. Looking at the board today confirmed that there is definitely a solder bridge to take care of.

 

[Mullet]

With a soldering pump, flux, and some soldering wick I was able to remove the bridge from the positive side of the circuit. Now on to the signal phase of this project.