PIONEER DEH-P9650MP
Manual de Servicio

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How to identify the cause of a power-down that is indicated by 2-times flashing of the red LED
The cause of a power-down that is indicated by 2-times flashing of the red LED can be identified by performing the steps 1 to 3 below: 1 Visual check with the power off 2 Tester check with the power off 3 Check with the power on

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1 Status check with the power off
Check if the cables and FFC cables that are connected to the Y DRIVE Assy are firmly connected.
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2 Tester check with the power off
1. Check between Vsus and SUSGND with a tester 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: If there is short-circuiting between Vsus and SUS OUT, and SUS OUT and SUSGND, the X Mask Module is damaged. If they are not short-circuited, check other elements to see if they are short-circuited. � How to check if there is short-circuiting on the Y DRIVE Assy: If there is short-circuiting between Vsus and SUS OUT, and SUS OUT and SUSGND, the Y Mask Module is damaged. If they are not short-circuited, 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 for short-circuiting between VH and PSUS with a tester Disconnect the cables that connect the bridge connectors between the Y DRIVE Assy and upper and lower SCAN Assys.
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� If there is short-circuiting in the upper SCAN Assy, one of Scan ICs in the upper SCAN Assy is damaged. � If there is short-circuiting in the lower SCAN Assy, one of Scan ICs in the lower SCAN Assy is damaged. � If there is short-circuiting in the Y DRIVE Assy, a circuit in the Y DRIVE Assy is short-circuited. If no short-circuiting is detected up to this stage, the power-down in question is proved not to be caused by shortcircuiting. Therefore, it is assumed that the power-down occurred because power had not been supplied to Vsus or VH for some reason.

3 Check immediately after the unit is turned on before a power-down occurs.
If the Vsus voltage does not increase, the POWER SUPPLY Unit is in failure. If the VH voltage does not increase, the VH DC/DC converter in the Y DRIVE Assy is in failure.
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4 Check the PD detection circuit.
If no problem is detected in steps 1 to 3, a power-down occurred even though the voltage was 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.

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PDP-427XD
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