Texas Instruments Extensa 660 Series Maintenance Manual page 92

Figure 5-17 External Keyboard Function Troubleshooting Diagram
Check Mouse Data
Check Mouse Clock
Check IRQ Signal
Figure 5-18 PS/2 External Mouse Function Troubleshooting Diagram
5-32 Troubleshooting Procedures
System Boots:
External Keyboard Checks
16
Check Keyboard Data
Yes
Check Keyboard Clock
Yes
Check IRQ Signal
Yes
END
System Boots:
PS/2 External Mouse Interface Check
17
Check U8(38813)
No
Pin12 EXT2DATA
Yes
Check U8(38813)
No
Pin13 EXT2CLK
Yes
Check U8(38813)
No
Yes
END
Check U8(38813)
Pin17 EXT1DATA
No
Signal
Check U8(38813)
No
Pin16 EXT1CLK
Check U8(38813)
PIN15 IRQ1
PIN14 IRQ12