If it's for the 64, it could be a cartridge like Action Replay or
whatever was made for the 64. It usually has a pass-through on the
expansion bus and a button to activate the cart. These carts were used
to *freeze* the computer and allow you access to all the current memory
to examine, change, or save entire blocks to disk. The logic chips were
probably used to transfer control electrically from the Kernel to the
code stored in the EPROM upon the push of the button.
Jeff Salzman
It's a white plastic cartridge with a 44-pin male card-edge connector and a
light blue plastic female passthru for the same type of connector. It has a
square black plastic button on top. It is (was) glued shut. Inside there is
an 24-pin EEPROM (88251A+ MM2716Q) with a Mitsubish Electric sticker
covering the window, a 14-pin IC (P234 DM7400N), and another 14-pin IC (EL
SALVADOR 1820-0328 7936 <Texas Instruments Logo> SN7402N). And two small
resistors and capacitors. On the circuitboard it says "NAVARONE (C)" and
next to the contacts where the little carbon pad on the underside of the
button makes contact, it says "TOP".