The 4 number code for the remote for the technics sa-dx940

SOURCE: Technics SA-DX940

Ratnesh, I have this same receiver and the fan only comes on at certain volume levels. Unfortunately I now live in an apartment and can very rarely listen to it that loud. I had the same problem for a little while until I thought about moving the receiver to the lowest shelf with nothing on top of it. This seems to have worked so far although it does still get quite warm. Good luck!

SOURCE: EUR647132 code list

http://service.us.panasonic.com/OPERMANPDF/SADX940.PDF
This is a pdf that has everything for the remote and reciever

SOURCE: F70 on my reciever

Most likley it is in need of repair. I suspect the output IC. Check for bad solder connections on the IC and voltage regulators.
Remove the speakers and see if it still happens (it probably will).

SOURCE: SA-DX940 recently stopped recognizing digital formats

Make sure you are using a digital connection, optical or coaxle cables must be connected, setting on receiver must match cable being used

SOURCE: Technics Receiver SA-DX940 subwoofer

I think this unit requires a powered sub-woofer.