CMoy reverse voltages
Jul 1, 2007 at 12:07 AM Thread Starter Post #1 of 4

CAvanessia

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Hi all,

I'm on my second CMoy, and I have no idea why the voltages are reversed when I tested them.

I'm at the first major section of Tangent's tutorial. I've hooked up the capacitors in the right direction (stripes are going the right way), battery clip, hookup wires (V+ and V-), and jumpers.

If I orient the battery location as up, then I shouldddd have all the positive power and led on the left and negative power and led on the right.

When I check with my multimeter, the voltage from V+ to the ground is coming up negative.

The tutorial said this is fine as long as I solder swap the V+/V- to the appropriate points on the DIP socket.

So if everything was working, I would have the V+ wire going in a straight line down to the DIP socket and same with V-.

My question is: Is this all I need? I can leave the V+/V- configuration now and just solder these wires to the opposite places on the dip socket? As in on the back of the board, these wires will form an X?

Sorry I'm in a rush to leave the house if this question is not as clear as it should. I basically don't mind them getting reverse voltages as long as the end result is right.
 
Jul 1, 2007 at 3:31 AM Post #2 of 4
Most likely you're just confused about how to do the measurement. Can you take a picture of the board with your probes on it, and say what polarity you think you're measuring in the pic?
 
Jul 1, 2007 at 3:45 AM Post #3 of 4
Technically, yeah you can do that. Crossing will give you the right voltages.

However...

The fact is, you may have some subtle fluke right now that's reversing the voltages, and once everything's finished, or you replace the batteries the first time, the voltages could go back to teh correct way frying your amp chip.

Definitely take a second look.
 
Jul 1, 2007 at 4:19 AM Post #4 of 4
As Tangent says, the more likely situation is that you have your probes hooked up wrong. The DMM has no way of telling which battery lead is positive or negative. It relies on you to tell it that. The common black lead, if you have the leads hooked up right, is supposed to be put on the negative terminal for the correct reading to show up. If the voltages are reversed then my suggestion is to swap the battery around which is probably the case for incorrect voltages. If you are reading it wrong and have it hooked up correctly without realizing it, crossing the power rails will give it mixed voltages and you will more than likely blow up your amp.
 

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