What is happening
You are called to a signal repeater that keeps burning out its driver.
The driver burns out unless the loop presents 320 Ω. One fixed resistor gives 180 Ω, and the second is set wrong.
Series circuitsRunning
Loop resistance
450Ω
Safe resistance
320Ω
Current splitter. Second resistor at 270 Ω. Loop resistance 450 Ω, Safe resistance 320 Ω. Currently loop resistance is over by 130 Ω.
What has to balance