SG90 180 degree servos only turning 90 degrees

Hi folks

Just had a set of SG90 servos delivered and having trouble with the servo module.

The example here: http://www.espruino.com/Servo+Motors#line=13,25,26 shows it moving from 0 to 1, which is actually only 90 degrees, not 180 as these servos support.

If you use:

analogWrite(pin, 0.04, {freq:50});

It goes to -90 ... and

analogWrite(pin, 0.15, {freq:50});

It goes to +90, demonstrating the full 180 degrees of motion... but the servo module doesn't seem to support it. They require either 1 (-90), 1.5 (0 or middle) or 2ms (+90) pulses at 50Hz

Any help would be appreciated.