Black Screen when Speed/Duration playback

[JotitaBlanco]

Hi everyone, im new to the forum.

I have read you quite some times, but this time im not finding a helpful answer to my error.

I'm editing small 25 second clip (24:11 actually).

Since the music has like a lot of  "in and outs" (Bruno Mars - Talking to the moon - Sickick remix) im editing it at 25% speed in one tab.

For testing, i use another tab with 400% speed.

When using this tab, if i set up the speed to 200%, i see half the video more or less

if i set it up to %300, a little bit less, and at 400% completely none.

400%

300%

200%

As you can see, the playback bar is red and it goes up when i lower the speed.

If i set it to 100%, the bar is full but yellow. (first part is blank)

Sorry to bother you all, but i would love if someone could give me a hand with this.

And sorry if english it's not all clear 

[JotitaBlanco]

Should have added that i tried changing the rendering method on sequence options.

Also i have tried forcing rendering, but still full black screen (with audio) at 400% playback 

[JotitaBlanco]

Sorry to pump this, i don't have a clue to what else to try.

Thanks