Apple Macintosh 6500 - Manual (Page 219)

Note: If your computer will not start after you’ve installed an expansion card,
DRAM, or the High Performance Module, you may need to press the reset
button on the main logic board. See the instructions listed under the problem
“The computer does not start and you have just installed DIMMs, a High
Performance Module, or expansion cards” in “Solutions to Common Problems
With Your Computer” in Chapter 9 of this manual.
WARNING To ensure reliable and safe operation of your system, never
turn on your computer unless all of its internal and external parts are
in place.
219 Installing Expansion Cards or Additional Memory