Hi,
its a it difficult to diagnose that issue, based on only a few infos.
Can you provide a wiring diagram?
It seems strange that the 180 Ohm resistor did not lower the voltage to approx 2.2 volts as it should.
Another question is, are you sure not to confused the both sides of the TR9608?
Are you aware of the wiring diagram on thingiverse ("Shield proposal")?
Regards Stefan
Yes, I used your diagram to make my shield and I have the TR9608 the right way.
I'm attaching photos of my shield and me testing. All the the resistor photos we're done with out using the shield with the resistor from the same package the ones used. The results are the same and testing directly shield.
Photo 1: OHM testing in the resistor.
Photo 2: The voltage with the same in line.
Photo 3: Same as above but no resistor at all.
Photo 4&5: My shield (not use an above photos what it results the same when I tried it)
Photo 6: My TR9608
Update:I pulled the Pro micro (TR9608) and pit it on my bread board. I tested a new 180 ohm and a 200 ohm resister. I even put them in one after the other for a total of 380 ohms resistance and I still burley detected a voltage drop. Could it be my new meter?