What aouut the Setup screen?  I see from my proto
archive
(all I have of a GiGi) that it has one.  More common mode
changes are typically made there. 
Yes, it does have a setup mode... I don't have my manuals
immediately available (they're all in storage), but if
you go into setup mode and select 'BA', that allows you to
set the BASIC mode.  Try digits like 0 and 1 to disable
and enable it.  You might also need to set 'LL' (local)
mode.
                                        Megan Gentry
                                        Former RT-11 Developer
+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL   | email: mbg at 
world.std.com         |
|                                |                                     |
| "this space                    |             (s/ at /@/)             |
|  unavoidably left blank"       | URL:     
http://world.std.com/~mbg/ |
|                                | "pdp-11 programmer - some assembler |
|                  (DEC '77-'98) |  required." - mbg            KB1FCA |
+--------------------------------+-------------------------------------+