In my emulator (RockNES), the game
Ghostbusters has a weird problem with the noise channel. First loading is fine. Now, if I load any other game, then reload the Ghostbusters, the noise channel becomes active after the title screen, like a quick continuous noise ticking sound.
No matter a soft/hard reset, the problem remains there. Any hints?
I'm in the proccess of hacking this game. I noticed that it was supposed to have a noise channel for the music, the pointer is there and all, but it seems to contain empty data. I haven't had time to figure out the sound data format yet. There is also a problem with the sfx for when you shoot the staypuft marshmallow man in the boss fight. That sfx is a noise channel effect, and it sometimes gets into an infinite loop. I changed some bytes semi-randomly and it fixed the bug, although now that sfx uses some of the next sfx for data, so it's not ideal but it's working for now...
From my notes:
0x4F3D: music channel pointers
0x4F46-5BBF: music
0x5C09: changed from $40 to $14 to "fix" the puft sfx
About your emulator, the looping is just occurring more frequently than it does on other emulators. If you open the game on fceux or mesen for example, the noise channel is still looped, but on a much coarser time frame, taking about 5 seconds to loop instead of that machine gun like sound on yours. Maybe that's a hint in the right direction.
Found the problem. For some reason, the last value on $400C was unchanged on reset/power up. So, I had to force a $400C:$00 write on reset/power up. Problem solved.