PDP-5000EX
83
5678
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7
8
C
D
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A
B
E
5.2.3 HOW TO IDENTIFY THE CAUSE OF A POWER-DOWN THAT IS INDICATED BY TWICE
FLASHING OF THE RED LED
A power-down caused by the power supply and one caused by a damaged drive part are both indicated by twice flashing of
the LED. The cause of a power-down that is indicated by twice flashing of the red LED can be identified by performing the
steps 1 and 2 below:
1 Tester check with the power off
2 Checks with the power on
1 Tester check with the power off
• Tester check between Vsus and SUSGND
Disconnect all cables from the X and Y DRIVE Assys and check if there is short-circuiting between Vsus and SUSGND
in the X and Y DRIVE Assys.
• How to check if there is short-circuiting on the X DRIVE Assy:
Check between VSUS and SUSGND on the MSK_MOD with the tester. If they are short-circuited, the MSK_Mod (SUS-
B/G) is damaged.
Check between the SUSOUT and PSUS connectors on the MSK_MOD with the tester. If they are short-circuited, the
MSK_Mod (MSK) is damaged.
Check other elements to see if they are short-circuited.
• How to check if there is short-circuiting on the Y DRIVE Assy:
Check between VSUS and SUSGND in the MSK_MOD with the tester. If they are short-circuited, the MSK_Mod (SUS-
B/G) is damaged.
Check between the SUSOUT and MSK-S connectors on the MSK_MOD with the tester. If they are short-circuited, the
MSK_Mod (MSK-R) is damaged.
Check other elements to see if they are short-circuited.
• Check for short-circuiting in the power supply.
Note that at the beginning of measuring with a tester, charging of an electrolytic capacitor may cause a phenomenon like
short-circuiting. However, the resistance will soon rise if there is no short-circuiting.
2 Check immediately after the unit is turned on before a power-down occurs.
If the Vsus voltage does not increase, the power supply is in failure.
3 Check the PD detection circuit.
If no problem is detected in Steps 1 and 2, a power-down occurs even though the voltage is normal.
Therefore, the PD detection circuit may be in failure.
By following the above procedures, the real cause of a power-down can be judged.
How to identify the cause of a power-down that is indicated by twice flashing of the
red LED
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