After Carlos enters the Photo Booth, the following shot is when it's the start of the Sentai footage as you can see in the following pics.    

After Silvy discovers that Carlos is the Black Ranger, it goes to commercial break and when it returns from break, it starts off in new footage and here's 1 of those shots that would be new.
As soon as you see this shot of Datascammer, it goes back to Sentai footage.
The Sentai footage ends once you see the interior of the Dark Fortress.
The first scene you see of the Black Ranger riding his Galaxy Glider is new footage.
Here's new footage of Datascammer due to being in the same shot as Silvy.
However once you see this close-up shot of Datascammer, it's back to Sentai footage.
This shot of Datascammer is Sentai footage but it's been flipped.
The shot of Datascammer being in the same phone as the phone booth is Sentai footage however when you see the black phone drop, it's new footage. In Sentai footage, the phone is green.
This close-up shot of Datascammer's feet and leg is when it's the start of new footage again.
The next close-up shot of Datascammer is Sentai footage however it's been flipped again, for whatever reason.
Here's the start of new footage.
Here's another new shot of the 5 Rangers.
Once you see the next close-up shot of Datascammer, it's back to Sentai footage again.
The shot of Datascammer growing is Sentai footage, they just added the Satellasers into the shot.
All Giant footage is Sentai footage. All footage of Psycho Red is new if he's in the same shot as Silvy.
All footage of the Space Rangers after they leave the cockpit of the Mega Voyager is Sentai footage unless they're seen in the same shot as Silvy.
This shot of Psycho Red is still new footage of him.
Once you see the shot of Psycho Red with his Sword, it's back to Sentai footage for him.
This shot of Pscyhos Red and Black is the start of new footage.
This shot of Psycho Black and Psycho Red looks to be when it goes back to Sentai footage however the shot has been flipped.
These shots is when it goes back to new footage.  
All of the remaining footage of the Space Rangers as well as Psychos Red and Black is new footage.
Here's new footage of the Black Galaxy Glider.
All footage of the Black Galaxy Glider is new.

To check on the extra Sentai footage that Datascammer comes from, please go to Mega 39