VFD with Copper Bus Bar Will Not Power On

Hi all! It's been about 6 months since we ordered these VFDs, but we're only now finishing the wiring and final assembly.
We ordered two VFDs in total. The first one was ordered on August 31, 2023. The second unit was ordered by me last July. The older VFD (on the left) powers up and works fine. It has red jumper wires on the primary power input bus bar.
The second VFD (on the right) uses a solid copper bus bar, and it has never powered up. We've verified that 120V AC input power is present on both units (marked in red in the photo). My question: Are there any known issues or differences with the copper-bus-bar version that could explain why it won't power up?

Laura wrote:Laura, if you're getting 120V AC into the drive but no signs of life, I'd first check whether the DC bus is charging. Sometimes the rectifier or pre-charge circuit can fail, especially if the unit has sat unused for a long time. Measuring P+ and P− should immediately indicate whether the input stage is functioning properly.

Laura wrote:I've seen VFDs shipped with different internal bus bar designs depending on production batch. The copper bar itself shouldn't be a problem, but loose internal connections or shipping damage could be. Also, make sure the control power supply is coming up—no 24V usually means the drive won't boot at all.

Laura wrote:Hi Laura, we see you purchased our GK3000-SP1S1-1d5.
After this VFD is powered on, please measure whether there is DC voltage at the main circuit terminals P+ and P− and provide us with a picture of the measured value.
Please measure whether there is voltage at the control terminals 24V and COM and provide us with pictures of the measured values.
When the VFD output is connected to a single-phase motor, it needs to be connected to the U and V terminals instead of the U and W terminals.

Thanks! I'll start by measuring the P+ / P− DC bus voltage and the 24V–COM control supply on the copper-bus unit. I'll also double-check the motor wiring to make sure it's on U and V, not U and W.