LED #1 and LED#2 ON but not chime

Hi.

I have got a 2008 iMac 20” with Intel 2.66 Processor.

When I turn ON the imac LED #1 and #2 turn ON, but I have not chime and fans do not turn on. I’m trying without LCD and HDD.

I was thinking that Graphic Card was broken but In that case the fans must turn on, right?

I tried an ebay graphics card, which theoretically works.

Does anyone know what's wrong?

Thanks so much.