I have HP Pavilion a6200 (GN556AAR#ABA), The power supply seems to be dead. Power supply model # ATX-250-12Z rev D6r. I was trying to buy the same unite, however I can not find it. All what I found is ATX-250-12Z rev D7r. I would be very thankful if someone can confirm, that I could get rev D7r to replace D6r. Thank you and Happy Holiday!