The F4 has an internal regulator which we try to bypass by feeding in 1.2V into the CAP pins. The CW313 doesn’t have an adjustable regulator included like the CW308, but you can try feeding in a slightly higher voltage (I’d recommend somewhere between 1.2V and 1.3V) by disconnecting the jumper on JP1 and connecting your power supply to pin 1 of JP1 (the one closer to the 5V test point) to see if that improves things.