[SunRescue] 4/330 Serial Console woes

[rescue at sunhelp.org]

I just had to use the word 'woes' in the subject.  :)

I have an SS 4/330, with PROM rev. 3.3.0.  I have tried:

Booting w/o kbd.
Booting w/o framebuffer card inserted.
Booting w/ diag switch ON.

I have also tried the combinations thereof (no kbd, diag ON) etc.

I cannot get any i/o on serial A (db25 on proc card).  I have tried
multiple known good cables and terminals (win/hypterterm,
linux/minicom).  When the diag rocker is set to ON, I get NOTHING on
screen or serial, just the diag LEDs come on (proc card).  I have searched
and searched and I can't seem to find a message with the same issues that
I am having.

I have also tried booting up with kbd and video attached (which works fine
btw.), and hitting stop-a to get to monitor.  From here, I have messed
around with the 'u' command, as such:

u ai
u ao

Attempting to set input to port A.  Do I have my syntax wrong on this ?
Whenever I use the 'u' command, the machine seems to lock (no output
ANYWHERE, and no more input accepted from the kbd).  I have also tried
setting the i/o to serial B.

Any and all help would be greatly appreciated.  Thanks in advance.