There are some burnt carbon resistors beyond recognition on a peavey tnt bass combo.so I need the schematic diagram

Try these schematics:

http://elektrotanya.com/peavey_tnt115s_sch.pdf/download.html

http://elektrotanya.com/peavey_tnt_100_1974.pdf/download.html

Scroll down to "Get Manual" at the web page and click on it to download.

Please note that on the first schematic above, the power amp schematic is way down beyond the parts list and layout of the preamp section... keep scrolling. ALSO the powoer amp shows a real WIERD connection where the output transistors drive against ground and the center tap of the power supply transformer for the power amp portion then bounces around with the audio output... that is a wierd connection but it is possible.