Moar IC voltages pins 4 and 8 swapped

[sangster]

Hi all! The title says it all... Noob question here. Just put the Moar together and am reading the IC voltage at pins 4 and 8 as 9.41 (@ pin four) and around 0 (@ pin eight). This is the opposite of what it should be. Any ideas on why this is the case?

Thanks!

[Ralfg]

Check to see if either the IC is in backwards or you have the ground and +9 volt wire in reverse.

[sangster]

Checked both. They should be correct...

[Ralfg]

Next thing to check is make sure your power supply is center negative. You can do that by putting the negative of your volt meter leads into the barrel and placing the other on the outside. Make sure it reads +9. Also how are you connecting it to your wires for testing?

[sangster]

I'm using a onespot (center neg) plugged into a typical jack. The image I've attached doesn't show the jack because I snipped it off to test flipping it around...

[madbean]

That's an unusual looking IC. Where is it from?

[sangster]

http://www.smallbear-electronics.mybigcommerce.com/ic-mc1458p-ti/

"IC MC1458P (TI)
Product Description
Dual bipolar op-amp used in many classic distortions and ODs
Replacing LM1458 (obsolete)"

[sangster]

I am using a Schottky 1N5817G in place of a regular 1N5817 at D9. Would that make a difference?

[madbean]

I am using a Schottky 1N5817G in place of a regular 1N5817 at D9. Would that make a difference?

None at all. What are your voltage readings on both sides of the 1N5817?

[sangster]

9.41 on the inline side and 9.27 on the other.

[madbean]

Well it's a bit baffling how you could have 9v on the 1n5817 and not on pin8 of the IC since they are directly connected. Are you sure you haven't confused pins 4 and 8? If you look at the trace diagram in the build doc, pin8 is the one connected by the fat red trace and pin4 is the one that appears to have no connection (it's actually connected to the ground plane).

[sangster]

So I messed around with it more last night and I think my problem was a short in the circuit. I can't see where it's happened, but after physically manipulating the thing, it's seemed to go away. Sorry for the rookie mistake... ugg... and thank you for your help!!

[Ralfg]

Glad you figured it out. Should have suggested reflowing everything.