Audio Systems: another sony protect mode problem, output transistors, electrolytic capacitors

Question
i am in college and brought my dads old Sony str-d365 2 channel amplifier with me i have two huge old Tannoy speakers that have absolutely fantastic sound plugged in it has recently been going into protect mode in less than 2-3 minutes into turning on. i do not have the vents blocked as i am playing an iPod through an RCA jack. i read somewhere that the gauge of the speaker wire can cause an issue (i am running 16 gauge Monster Cable) and also that the impedance of the speakers is the most likely problem. i was running the speakers through a different amp but one of the channels didn't always work so i brought this one with me to school as i knew it worked. i understand electronics a little and have a friend that is an electrical engineer so if you can help me please be specific and i can probably fix it.

thanks,
       Chris  
(i don't know if i get an email notification or not so my email is )

Answer
The most common cause when a unit is hooked up to a new set of speakers is:

-  The impedance of the speakers donot match to the amplifier
-  The speaker wires are touching at the terminals causing a short condition to the amp
-  The new speaker has a shorted voice coil or internal short

Those are the first things to check.

If everything looks okey then it could be an internal electrical problem inside the amp.   With volume control turned down, turn off the amp and disconnect the speakers at the back of the amp.  Then turn on the amp and if it goes into protection mode then the problem is internal. It will require testing or troubleshooting of the amp.  Most common failures are:

-  Blown output transistors
-  Shorted electrolytic capacitors in the power supply section.

So, let's see if that gets you  started on the pathway for a solution.  Let me know more if you need.