HEIDENHAIN TNC 415 (259 9x0) Service Manual - Manual (Page 58)

SERVICE MANUAL TNC 415B/425
Page 55
Issue: 20.08.95
10.3 Checking the Power Supply Unit
Two low-voltage fuses are located on the POWER SUPPLY assembly. The fuse F 2.5A protects the output
voltage of +24V BE (not required for TNC 415B/425), and the fuse F 4.0A protects the remaining voltages (see
block diagram in section 10.2.1). If an error occurs in the power supply (all voltages missing), first check the
+24V at the supply line (2-pin terminal strip X31) and then the low-voltage fuse F 4.0A.
The voltages can be measured directly on the power supply board, the processor board and the CLP board
(sections 10.3.1 and 10.3.2).
The values and their tolerances can be seen from the corresponding tables. If the measured values deviate
distinctly from the values in the table, the power supply assembly is defective.
*
Observe the safety instructions!
The power supply unit does not work without load.
(Basic load is required)