MOTM

I just finished a 490 last night. Fired it up today to do the trimming and found the resonance pot has no detectable effect.
It passes audio and the Freq controls all function. I pulled one end of the iABC resistor (R29) and measured current - approx 0.2mA with a 68K resistor. Replaced with a 39K resistor and I got around 0.3mA.
Double and triple checked all parts, IC, diode and cap orientations, etc. Everything checks out. I also traced nearly the whole circuit with the DMM and that checked out OK, too. 
This leads me to believe I have a bunk 5517 (this was sent to me with the pcb so I don't know its source. ON semi chip).

I'm hoping this is a problem that has come up before and the mystery can be solved.
Any suggestions, areas to re-probe, etc would be greatly appreciated.
Just wanted to throw this out there for suggestions before I pull and replace the 5517.

Thanks,
Phil