HEIDENHAIN TNC 407 (243 020) Service Manual - Manual (Page 55)

D-i3292 31-O
SERVICE MANUAL TNC
Issue:
01.09.1995
Page 48
10. Visual Display Unit BC 1 O/l
1 Overview
BC 110 Id. No. 254 740 01 BC 260 520 01
0
0
10.2. Checking the Visual Display Unit
260 520 01
If the screen remains dark when the machine is switched on first check the power supply (line voltage) of the
VDU. If the voltage supply is functioning properly, a square highlighted field can be generated on the screen of
the VDU (which must be switched on) by pressing the external test button on the back side of the unit.
Highlighted field
External test button
If the VDU generates this highlighted field, the PLC graphics board in the logic unit is probably defective.
If however, the VDU remains dark after the test button was pressed, the VDU is defective and must be
exchanged.