Is my Ultra5 dead?

Hi all and sorry for my poor english!
One week ago I bought a Sun Ultra 5 on Ebay.
Yesterday it arrived but because of my monitor (it can handle 1024x768x75
and below resolution(s)) I can't see anything, so I spent yesterday evening
searching for informations in this newsgroup and on some forums.
Today morning I built two Null-Modem Cables (following instructions at
http://www.sunhelp.org/unix-serial-port-resources/serial-pin
outs/#nmdb9.link) and tried the serial connection from my linux box! Here
is an example of what I got with both cables:

$ cu -l /dev/ttyS1 -s 9600
Connected.
????333bÍæg3Æ????
à Ã8< ???> xðøðøðàÀààÀààÀ??àÀ??ÀÀÀàààààðð ððøøøø|ø|øü| <>< ç<
Ï ??????Æ?ÎÇÆç;çwsss3³³33»³??ÛÍÙmÛ%I ím­-?­­­¥µµõµõ×UþUUÿúÿÿúÿªªú«êjk{Z?
?ZÖÒ¶¶Ö¶¶6fìfîÌÌÜ?9yR! øcu: Got hangup signal

Disconnected.
$

(Got hangup signal = I forced power off with the switch on the power supply)

Obviously the keyboard is disconnected when I try to get the serial
connection.

More details:
When I turn up my U5 by the switch on the power supply, I can see that HD,
fans, cdrom are workin and keyboard leds flashing (sometimes I hear also a
beep, sometimes not) but if I press the power button on the keyboard or on
the frontside I don't see any activities and the power led is constantly
off.
I can hold down the Stop and N keys for five minutes, but nothing happens
(POST doesn't start, no led blinking on the keyboard).
The video card is the one on-board (PGX24).
I checked if hw components were right plugged in their slot...OK
Tried with cu and minicom on the linux side...
Tried with hyperterm and teraterm on the windows side... (with different pc
too)
Tried with different baud rates and parameters...
Tried with another ATX supply (even if the one shipped in appears to be good
(I can open the cdrom tray, for example))...

NOTHING!

A very strange thing: I can get the "strange characters" output even if the
keyboard is connected to the U5! This sound very very strange to me!

Another thing that I want to point out: Power LED is ALWAYS off and, when I
turn on the system with keyboard plugged in, I DON'T HEAR the beep (I've
read in many articles on the net that the beep means "hey, I'm booting
well").


So... is my Ultra5 dead?

Bye/Antonio
Milan/Italy
.