Marantz SR-4002 AV receiver Sound Problem (?)

[Comp_Sci_hater]

Hi everyone

I just got my hands on a Marantz SR-4002 AV receiver, it stood in my living room for the past 12 years. The complaint from my parents is that the sound is very quiet even on the highest possible volume, furthermore the receiver wasnt redirecting the hdmi input from our PS4 to the TV. The other thing that i am not sure is an issue with the receiver or with me, is that i couldnt get all the channels to work (surround left, front left, center, front right,  surround right). I connected the audio to the AUX port on the front and the only channels playing sound were Front left and right, i couldnt figure out how to make all of them work for 4 hours. After that i noticed the surround channels and the front channel were outputing sound, the sound was just so quiet that even with my ear on the speaker i could barely hear them.

Does anybody own this receiver or even the newer/older version and could give me some tips how to set this thing up to work on all channels? The quiet sound is probably something messed up in the circuit, same with the HDMI, but the problem with only front channels playing reasonable sound is strange, because even in the multi channel stereo preset they were quiet.
Thanks in advance for all the responses.