[QUOTE=RetroHacker] I don't have a K731, if I did I'd measure it for you. It looks like that radio is covered in Sam's 653-12. Try to see if your local library has it, or maybe someone here has it and can send you scan. Having the schematic is really useful.

Very good pointer and i fully agree. I promise if i find the specs first i'll post it here for anybody who wants to do more for their hobby.

Please dont get me wrong, i'm really having fun doing this. I think i got used to my other hobbies; building/ flying model helicopters, which requires so much challenge and precision (and i like it). Now that i've got this old radio from a neighbor which was humming so badly, my instinc kicked in,..not expecting that i will be real crazy hearing the sound after doing the mod plus the real satisfaction of doing it.. Well i always thought old things are always inferior especially with electronics, but boy, was i wrong. Then, i asked myself what if i do more and who knows?
So excuse me for my obsession guys, but i can't stop the "too much fun" now. .. Looking for that B+ is getting more exciting and challenging for me ( and i like it)!!

Ps. Planning to start a thread pertaining to models that sounded better than k731.