U1 Pin 8

[Nu-tra]

I'm not getting anything on pin 8. I have -18 on pin 4 but all I get is 3.76v on pin 8 on U1-3. I plugged the c84 in to listen to it and it was really noisy with a slide whistling sound. Weird

NU-TRA

[Nu-tra]

Just double checked everything and all looks good. Cant figure out why i'm having this problem

Thanks

[tpryan]

Check the polarity of the tantalum caps connected to B+. Are any of them getting warm or changing color?

[Nu-tra]

B+? Ok will check

[Nu-tra]

Yup c34 was backwards

[oshearer]

checked both tantalum caps, both are installed the right way around, or at least I believe so. The stripe on the cap is on the positive side, right? Is there anything else that could be the problem. I've reflowed all the joints that look like they might be creating a problem. I'm stumped.

[dkatz42]

checked both tantalum caps, both are installed the right way around, or at least I believe so. The stripe on the cap is on the positive side, right?

There is always (at least in my experience) an explicit "+" or "-" on polarized caps. Is the stripe you see really a minus sign? That would explain it. My modules are 800 miles away so I can't look myself...