Question on older amp: Sony TA-N330ES Ohm load Questions

I just picked this amp up to run additional speakers and I have a question about the output if anybody might be able to help. 

I would like to run one side A with full range speakers, and the other B as a bridged mono connection for a subwoofer.  I would run A speakers at 8 ohms and the subwoffer at 8 ohms as well (at least I think it would be 8 ohms, it is a car speaker with two 4 ohm voice coils that I would run in series if that gives an 8 ohm load)  The main thing that I don't know is if I could run two speakers in stereo mode while running the Sub in mono.  I might just have to get two subwoofers and run them in stereo, or just stick with 4 full range speakers.  The amp shows me these set up modes:

Speakers A, B:  4-16 ohms

Speakers A & B; 8-16 ohms

Speakers A, B Mono:  8-16 ohms

Speakers A & B Mono:  16 ohms

I also don't know if it is possible to get a low pass for the sub at speaker level.  This amp only has one set of inputs so I can't low pass it before the amp. 

Here are the specs from another chat a few years ago.  This is an early to mid 90's amp but I believe that it is still good quality even by today's standards...  Plus it was only $125 at a yard sale.

Oh, no :(  I just found out that the amp is not working.  I am trying to get ahold of the seller, but it might not be possible.  I looked over all of the circuits and found that the piece that is burnt out is a Sanken Transistor  http://www.mcmelectronics.com/product/SANKEN-SANKEN-/2SC2921   The protect light is lit up on the amp and nothing is working so I am hoping that this is the only burnt out part.  All of the caps look perfect and there is nothing else on any of the boards that I can see any damage to.  If anybody here knows if this part would fail by itself please let me know, I just don't want to replace it and find out that it is common for many other parts to fry at the same time.

Bad luck for me, but hopefully I can either get it up and running or get a refund.

Thanks, Neil