MiTAC 7521 PLUS/N - Manual (Page 117)

116
7521 7521 Plus / N N/B MAINTENANCE Plus / 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.
Test
OK?
YES
NO
Try another known good
SDRAM modules.
Correct it.
END
YES
NO Replace mother
board or into
board level
Troubleshooting.
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:
U24, U15
U18, U22
U25, U29
U19, U23
U26, U30
RP20, RP22
RP23, RP25
RP41, RP44
RP54, RP53
RP40, J6
R588, U508
Signals:
MDR[0~63]
MD[0~63]
MAB#[0~9]
MAB[10,13]
MAB#[11,12]
SCASA#,
SRASA#
WEA#
DQMA#[0:7] CSA#[0:3]
CKE[0:3]
SDRAMCLK[0:3]
SMBDATA
SMBCLK
Test
OK?