Siemens PC 870 manual Removing Proceed as follows Computing unit

Maintenance

4.2.2Panel PC 870

Removing the	Proceed as follows:
computing unit

Knurled

1.Disconnect the power supply.

2.Swing open the mounting panel to obtain access to the rear of the PC 870.

3.Loosen the four (retained) knurled screws which secure the compu- ting unit to the rear side of the operating unit (see also Figure 3±3).

4.Swing the computing unit away to the left, whereby the two left clips act as hinges and thus prevent an unintentional releasing of the computing unit.

	Computingunit,	90￿
		swungaway by
Computing unit

Operating unit

Clips acting as hinges

Fig. 4-3 Swinging the computing unit away from the operating unit (viewed from above)

5.Remove the cable connectors K1 and K2 of the operating unit (see Figure 4-4) from their corresponding counterparts on the computing unit.

6.Lift the computing unit off the hinges of the operating unit and place it down carefully.

If necessary, you can now remove the operating unit by loosening either the screws or, depending on the version, the six clamps which secure the operating unit to the mounting panel (see Figure 3-3).

4-4	SIMATIC Panel PC 670 / 870 Operating Unit, Equipment Manual
	Edition 07/01