SamyGO

Hello', I'm new on this forum and I have started reading posts about mods on Samsung TV.
I have UE32J5200AKXZT, I will try to enter on the service menu and my main interest would be to enable PVR functions, if possible.
Is there any list of which tv it can be enabled?

First of all you should start by disabling updates and blocking them on router ASAP. Without it NO GO

Yes, on my tv OTN is now OFF and updates blocked on my Fritzbox router.
For PVR on my menu' I only see Numb or PVR records set to 0.
I didn't see a page for PVR enabling yet. Thank you

You need EXTENDED service menu for enabling PVR. Also you might need rooting

Thanks. I found the menu enabling the EXTENDED service menu and PVR is ON but even after reboot I don't see any change in the GUI and software in order to use PVR. I have attached an external HDD in the USB port as first point.

As long as you don't change TV model or possibly local_set, PVR values are restored after reboot. Try to only exit service menu using FACTORY key after setting values, without rebooting, then check PVR.
Know that you can easily brick your TV if ever you decide to try changing TV model.
Changing localset is much safest. Maybe a clue there: viewtopic.php?f=90&t=9921&p=82428#p82428

As I have a J5200 which model type I should set to avoid issues, i.e. J5500? Of course I don't want to brick the tv and I hope with your help in this forum I can get success!

No idea, there's no rule, otherwise there wouldn't be any risk
You tried localset trick? And exiting service menu?

In my case I tried already to reboot the TV and the settings are saved. PVR function is still ON but I don't see changes in the menu' or way to start recording. My RCU does not have a recording key but only for play/pause, rewind, stop, so I suppose that, if it's possible to implement recording, there should be some new menu.

If you found a way to send FACTORY key, you must be able to find REC key as well