Instruction manual

NGA 2000 MLT Hardware
TROUBLESHOOTING
10 - 1
Emerson Process Management GmbH & Co. OHG
Instruction Manual
90002929
07/2006
10. Troubleshooting
Take care of the safety instructions as given at the beginning of this manual
while working at and inside the instruments!
Working inside the instruments is subject to briefed personnel familiar with
potential risks!
10.1 Instrument has no function (LCD display is dark)
Possible Causes Check / Correct
a) External supply voltage is absent: Check connection mains line → MLT / PS
MLT 1/4: Check external power supply
- DC polarity is reversed Check electrical supply
b) Possible internal failures: Check internal voltage supply (Section 11.1.1)
MLT 1/4: Check fuses of PCB “LEM” (Section 12.4)
MLT 2: Check internal fuses F1 and F2 (Section 12.4)
c) Internal connections incorrect or absent: Check internal connections:
Check whether PCB “ACU” is in correct place
(Fig. 1-31)
Check PCB's “ACU-AFP” (front panel)
connection cable
d) PCB “AFP” board or LC display defective Exchange front panel (see 12.2)
e) PCB “ACU” defective: Replace ACU (see 12.3)
NO FUNCTION (LCD DISPLAY)