My old ipad is not turning on. It is fully charged, tried pressing home button and on/off button together. No logo comes. What to do?

If the iPad will not power-on, how do you know that the iPad is fully charged? There is no external means by which the state of the iPad battery charge can be determined.

You should start by substituting a known good Power Adapter and cable. More information about charging issues can be found here:

If your iPad won't charge – Apple Support

When your iPad is connected to the Power Adapter, if charged but shut-down, the iPad will reboot automatically.

After substituting your Power Adapter and cable, connect them to your iPad and allow to charge for at least an hour. Then, whilst still connected to the Power Adapter:

• On an iPad with a Home button: Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.
• On other iPad models: Press and quickly release the volume up button, press and quickly release the volume down button, then press and hold the top button. When the Apple logo appears, release the button.

If iPad still doesn’t turn on, or if it gets stuck during start up, see the Apple Support article If your iPhone, iPad, or iPod touch won’t turn on or is frozen.