MiTAC 7521 PLUS/N service manual 116

7521Plus / N N/B MAINTENANCE

8.5 MEMORY TEST ERROR

Either on board or extend SDRAM is failure or system hangs up.

MEMORY TEST ERROR

1.Check if on board SDRAM chips are no cold solder.

2.Check the extend SDRAM module is installed properly. ( J6)

3.Confirm the SDRAM socket is ok, no band pins.

YES

Test	Correct it.
OK?
	NO

Board-level

Troubleshooting for

Memory test error.

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:

Try another known good SDRAM modules.

NO

Test

OK?

YES

Replace mother board or into board level Troubleshooting.

U24, U15	MDR[0~63]	CSA#[0:3]
U18, U22	MD[0~63]	CKE[0:3]
U25, U29	MAB#[0~9]	SDRAMCLK[0:3]
U19, U23	MAB[10,13]	SMBDATA
U26, U30	MAB#[11,12]	SMBCLK
RP20, RP22	SCASA#,
RP23, RP25	SRASA#
RP41, RP44	WEA#
RP54, RP53	DQMA#[0:7]
RP40, J6
R588, U508

END

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