Casio privia px-750 how to do a factory reset?

It is a known issue on this model.

https://www.google.com/search?q=%22casio+privia+px-100%22+pedal+not+working

Reset....but

https://www.fixya.com/support/t21517149-reset_privia_px_110_back_factory_setting

https://www.google.com/search?q=%22casio+privia+px-100%22+reset

..

ask casio directly or GOOGLE it

You don't need to reset factory.
You just need to change the setting of LOCAL CONTROL.
Lets start :::
While holding TONE / SETTING button,press key D#7 at 7th octave (highest octave on the right hand). Then release. That's all.
Then the sound must be heard..

http://www.circuit-encyclopedia.com/listinfo-67-111.html
Download Service Manual for PX-410R as PX-410R is the same model as PX-575r.

Casio don't supply PX330 drivers for IPAD.
Get a Windows 8.1 tablet or connect PX330 to a desktop PC and use IPAD to Remote control that PC.

TRY this;-
1. Turn off the digital piano
2. While holding down both the (TONE) and (FUNCTION) buttons, press the (POWER) button

You can download the service manual for free from manualslib.com

Try this
1. Turn off the digital piano
2. While holding down both the (TONE) and (FUNCTION) buttons, press the (POWER) button

Turn the Keyboard off the press and while holding down the [TONE] AND [FUNCTION] buttons power on the keyboard. Wait until all reset is done.

The problem you're encountering is actually a feature, called stretch tuning. While real pianos are tuned in this way it's meant to sympathise with their natural 'organics' and might sound wrong on a digital instrument. The solution is to turn stretch tuning off. The manual should be able to tell you how.