VREF is way too high

[mark2]

I have a voltage divider (between 8.9V and GND) and expect the VREF to be ~4.5V, but it's reading 8.3V.

I'm wondering if anyone can give this a second set of eyes and tell me if you see anything boneheaded I did that would pull it up that high.

Edit: 1. Ignore the clip/RIN mixup, that's not on the real board.  2. And I've done a variation of this circuit quite a few times without problems, so it's possibly an assembly problem but boy I'm pulling my hair out on this one.

[antonis]

R9 wrong (very high) value or "open"..??
(in case of "open", your DMM impedance sets the voltage divider lower part resistance..)

[Rob Strand]

One odd thing about your schematic is there's ground symbols with and without "GND".
Are you sure the two grounds are connected together on the PCB?

[mark2]

R8 and R9 are correct, that's the first thing I checked

The GND inconsistencies in the schematic didn't make their way to the PCB.

HOWEVER... in checking out the latter I realized I may have reversed my opamp. So I'll go fix that first and check. Given that the opamp is one of very few things connected to VREF I think we may have found a winner.

Thanks! I'll report back.

Edit: by the way, I couldn't find any orientation markings on this TL074CDT at all. No dot, no half moon. I'm just relying on the orientation of the text printed on it.

[Phoenix]

Edit: by the way, I couldn't find any orientation markings on this TL074CDT at all. No dot, no half moon. I'm just relying on the orientation of the text printed on it.

CDT, that's a SOIC package, the side with pin 1 is bevelled.

[mark2]

I hadn't noticed the bevel marking before; good to know!
And fixing the orientation of the opamp fixed this issue.  On to the next.

Thanks everyone!