Not properly grounding the three digital ports

[Rimbaldo]

Hi! I wired as indicated, but used another power source to get 5V and higher current (MCU kept resetting when using it to provide the 5v), but grounds are all common and checked. I’m using an Attiny167 (Digispark Pro), and when I send the digital out to LOW at any of the three pads, it gets from the voltage on the voltage divider on the PAD to 0.15V, but never grounds it. In none of the three ports I can ground it properly (0V) from the Attiny to control the volume, tracks. bit connections seem proper, grounds are all checked, and wires from the ports also.

Do you know why this could be happening? Should a transistor as a switch be used instead on each pad?

Thanks!