replaceScene don't changes the screen

After AppDelegate I can create the first scene and them I do replaceScene for second, but when I try back to the first using replaceScene again it don’t change the pictures at all, but background sound and fps seems ok. Some help ?

void GameScene::backMainMenuCallback(cocos2d::CCObject* pSender) {
    CCScene *s = MenuScene::scene();
    CCDirector::sharedDirector()->replaceScene(CCTransitionFade::create(0.5, s));
}

I need more info …

Does it work OK if you don’t use the transition effect?

I just figured out what is happening, I just puted last scene on pause, when did replace for new one this, was in black, thanks for your answers.