MiTAC 7521 PLUS/N service manual 118

7521Plus / N N/B MAINTENANCE

8.6 KEYBOARD(K/B) TOUCH-PAD(T/P) , ESB TEST ERROR

Error message of keyboard or touch pad failure is shown or any key doesn’t work.

KEYBOARD TEST ERROR

Check if K/B or T/P cable installed

properly.

Board-level

Troubleshooting for

K/B or T/P test error.

Check if U14, J5, J515 and J502 are cold solder or not.

	YES
Test	Correct it then
OK?	end.
	NO

YES

Test

OK?

NO

Replace or Re-solder U14, J5, J515 and J502

Try another known good K/B or
T/P (Internal or external).
	YES
	Test	Replace the faulty
	OK?
		K/B or T/P then end.
	NO
	Replace M/B or
	into board-level
	Troubleshooting

Check the following parts for cold solder or one of the following parts on the mother-board may be defective, use an oscilloscope to check the following signal or replace the parts one at a time and test after each replacement.

Parts:		Signals:
U14, U31	CHARGE BD	KI[0:7]	IOW#
R520, RP18	SWITCH BD	KO[0:15]	IOR#
FA5, L3		H8/T_DATA	IRQ1
F1, L53		H8/T_CLK	IRQ12
L54, RP7		H8_KBCS#	SD[0:7]
U11, L55
C262, J3
J501

118