Looks like a L21-30 plug mount in rear of computer.
----- Original Message -----
From: "Sridhar Ayengar" <ploopster at gmail.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Monday, June 04, 2007 2:39 PM
Subject: Re: Got a LISP Machine on Sunday
  Keys wrote:
  Had a Symbolics 3640 dropped off on Sunday
evening along with a Symbolics
 model OP36-DISP display. Missing are the keyboard, FD, and all the needed
 cables (power cord also). I opened the front door and saw two hard drives
 mounted inside. Will also be looking for manuals and some software.
 Anyone would information please email me. 
 Is the power cord that non-standard?  I would understand that they might
 need something beefier than an IEC C13/C14 for how much power something
 like that pulls.  Is it a C19/C20, maybe?  That's what my DEC GIGAswitch
 uses.
 Peace...  Sridhar