Harman Kardon avr525

I would like to get comments on my personal findings on the Hk 525 that I recently purchased used. First of all I would like to say that I also got a HK 146 which I have been using for a couple of years and I love it but it lacks power for my polk speakers( Rti10's) so I was looking out for a more powerful Hk amp and found the HK525 used. The first thing I noticed is a lag in audio feed from digital input from my hd cablebox. When I switch channels there is always a lag to bring in the signal whether it be 2ch. or 5.1ch depending on the program. The second thing I noticed is everytime I turned off the unit(525) it makes a click or snap sound from my speakers. These two issues are new, since my avr146 never had these issues. The third thing I noticed is that after having it on for a while in my cabinet with 3" clearance on top and the door open it get very warm, then when I turned it up to around -5 it shutdown. I turned it back on and it did the same thing only when the volume got up there again. I tried this the next day when the amp was cold and it did not shutdown. HK says that this model has a fan but there is no way to test if it is working at home and it only comes on at higher temp. when it is at higher volumes and you won't hear it then. My only question is should I stick with my avr146 or avr525. Or another option. I would also like info on the settings people are using with the avr525.
Thanks in advance for any comments.
After some further testing and checking my connections I realized the click or snap noise only comes out of center channel.