PWM Duty Cycle discrepancy when monitor not plugged in

[geel9]

Hello,

I am controlling multiple Talon SR motor controllers using PWM outputs.

The frequency is 50 hz and the duty cycle for a "neutral" signal is 0.075. To go full backward, 0.050 and full forward, 0.10

When an HDMI monitor is plugged in to my Raspberry Pi Rev. 1 B+, setting a GPIO pin to 0.075 does just that -- it works.

However, if an HDMI monitor is NOT plugged in, the duty cycle seems to be scaled up. In order to get an ACTUAL duty cycle of 0.075, I need to instruct pi-blaster to set a duty cycle of 0.066 -- a 1.1364 multiplier.

[YemSalat]

Are you sure you're not over-volting / 'over-currenting' your Pi?