[j-nsp] Dead M40- troubleshooting?

[billp]

Ok... so we had a working M40 in our lab, and we decided to
attempt to add additional memory.  Bought what we thought
was matching memory, added it, plugged it in.  RE was a
RE-xxx-256 (old RE.)

LCD reads: Boot ROM, Starting routing engine.
Serial console has no output at all.
VGA (tried it on a lark) has no output either (probably shouldn't,
but anyway....)

Power down, take out new memory, power up.  Same thing.

Dead RE?

I also attempted inserting an RE-333-768 -- same result,
although i'm not sure if this RE is compatible with the
M40 chassis.  Is it?  If so, did something in the chassis
go south?

Any additional troubleshooting tips anyone can offer?

Anyone seen this before?

No, calling JTAC is not a luxury I have on this router,
being it is a lab router... :-\   

bill