Compaq 386 manual U13 Even

Maintenance and Service Guide 8-5

Table 8-3. System Board (assy. no. 000558) Switch Settings

Switch	Switch
Position Number	Positions	Function
1	ON	Reserved
2	ON	Coprocessor installed
	OFF	Coprocessor not installed (default)
3	ON	80287-3 or -6 coprocessor speed 4 MHz
	OFF	80286-8 coprocessor speed 8 MHz (default)
4	ON	CPU boot speed 16 MHz except when
		accessing diskette drive; then 8 MHz
		(default)
	OFF	CPU boot speed 16 MHz always
5	OFF	Reserved
6	ON	COMPAQ VDU, COMPAQ ECG, compatible EGA,
		RGBI, or VGC (default)
	OFF	Third-party monochrome
7	ON	80287-3, -6, or -8 coprocessor or no
		coprocessor installed (default)
	OFF	80387-16 coprocessor
8	ON	Reserved

Table 8-4. Locations for the Processor, Coprocessor, and System ROM on the System Board (assy. no. 000558)

Location	Description
U13 EVEN	System ROM
U15 ODD	System ROM
U42	Coprocessor (80287-3, -6, or -8)
U60	Coprocessor (80387-16)
U76	Processor (80386-16)