pwn on pin 9/10 not working depending on sketches

Using Arduino Programming Questions
1

Hi everybody

I am working on arduino since 2 years, and i am quite familiar/advanced with it, but i got today a really strange problem with pwm on arduino uno

pwm on pin 9, 10,11 are working great using "fade" exemple, indeed the problem is not "electrical".

When i am using my sketch, the pwm is not working with pin 9 or 10, only digital output, but it is working replacing word by word 9/10 to 11.
Pinmode is correctly configured in the setup.

In other words :

NOT working ( leds are OFF )
analogWrite(9, 57);
analogWrite(10, 125);

WORKING ( less are ON )
analogWrite(9, 255 );
analogWrite(10,255);
analogWrite(11, 125 );
analogWrite(11, 57 );

I was thinking about "dependencies", but i only use , and libraries, and no shield.

Do you have an idea ?

2

coco3d:
I was thinking about "dependencies", but i only use , and libraries, and no shield.

Your thinking is right. As per the Servo Library Reference page:

On boards other than the Mega, use of the library disables analogWrite() (PWM) functionality on pins 9 and 10, whether or not there is a Servo on those pins.

The servo library makes use of the timer hardware that would normally be used to drive pins 9 and 10. You can't use the hardware for two different functions at one time.