So far as I can find out the 10 blinks of the power light is Kickstart 3.x thing. Have you got KS3.x installed?
Apparently it's to give you a chance to get a debug dump from the serial port.
I don't therefore think the number of blinks on the power light really means anything here.
I've also found an indication that a black screen means no CPU detected. I didn't find anything pointing to RAM.
edit to add:
You may find this link useful. Seems to suggest the black screen could also be CIA chip related.
http://www.lemonamiga.com/forum/viewtopic.php?t=13978