A diode stack is aligned when all of the heat sinks are visually aligned with each another from the bottom isolator to the top isolator

Disconnect the fiber optic and power supply cables of the faulty IGCT as well as the one directly above it.

Shut down the PCS6000 according to the “PCS6000 Lockout/tagout procedure”,3BHS600000 E22.

　　1. Shut down the PCS6000 according to the “PCS6000 Lockout/tagout procedure”,3BHS600000 E22. 　　2. Switch off MCB -Q306 to interrupt the 3AC 400 V input voltages of the AC/DC converter (24 V power supply). 　　3. Wait until the IPC shut-down is finished (approximately 5 minutes). 　　4. On the UPS -G302 turn the selector switch “Bat.-Select” to “Service”, then back to previous value (see Fig. 8–2) to interrupt the 24 V battery supply voltage (the yellow LED “Bat.-Mode” must be dark).

　　The PCS6000 is a medium voltage high power device. 　　High voltage in the PCS6000 can result in serious injury or DEATH and damage to the equipment. 　　Parts replacement and other work on the PCS6000 must only be carried out by qualified personnel in compliance with local regulations. 　　CAUTION Cooling fans can start automatically! 　　The water cooling system and the cooling fans can start automatically as soon as the auxiliary voltage is switched on or when the EMERGENCY OFF button is released, even if the PCS6000 is de-energized. 　　Switch off the corresponding motor protection switches (see diagrams contained in the cabinet specific documentation) to shut down the cooling system. 　　NOTICE Risk of component damage. 　　PCS6000 parameters are set during commissioning of the device and must not be changed afterwards. 　　Running the PCS6000 with incorrect data can result in improper operation,reduction in control accuracy and damage to equipment.

　　The PCS6000 is a medium voltage high power device. 　　▶ High voltage in the PCS6000 can result in serious injury or DEATH and damage to the equipment. 　　▶ Parts replacement and other work on the PCS6000 must only be carried out by qualified personnel in compliance with local regulations. 　　▶ Low voltage remains on the auxiliary energy distributor of the converter control system after the PCS6000 has been switched off. 　　▶ External auxiliary and control voltages (eg, of measuring circuits) can also remain even if the internal auxiliary power supply has been switched off. 　　▶ Before working on these circuits, verify that the corresponding external voltage sources have been switched off and secured according to the safety rules. 　　High temperatures, risk of burns! 　　▶ Rails, reactors, resistors and fuses can be hot. 　　Cooling fans can start automatically! 　　The water cooling system and the cooling fans can start automatically as soon as the auxiliary voltage is switched on or when the EMERGENCY OFF button is released, even if the PCS6000 is de-energized. 　　Switch off the corresponding motor protection switches (see diagrams contained in the cabinet specific documentation) to shut down the cooling system.