Unlocking the Navigarion System MFD Radio in a 2001 VW T4 - Methods and Steps

Hello. A few days ago I bought a vw t4 2001. In the car is the original Navigarion System MFD radio, I have a four-digit code for the radio. But unfortunately I can not write it, because the panel does not react, I turn the knob and nothing. I disconnected the battery for 24 hours and nothing. I also tried to leave the radio on for one hour with the ignition but it also did not help ... maybe someone knows how to unlock it. The wife of the owner of this car had previously entered the wrong code twice and blocked it. Previously, he had this problem but managed to solve it by disconnecting the battery for 24 hours. This time it did not help. Maybe you need to press some two buttons that unlock the radio? I am asking for help, greetings.

Turn on the radio on the ignition and wait for the block to release, it may take longer than one hour.

Thanks! Everything works correctly. The first time after an hour, nothing helped, I repeated the operations, it was less than an hour on the ignition and showed up 1000 later I entered the code and everything is ok! Greetings...