Diamond Aircraft DV 20 E 2022, Airplane Maintenance Manual

Page: 481 / 903

AIRCRAFT
DV 20 E AMM Indicating Systems
Doc # 4.02.25
Rev. 2
31-60-00
Page 101
15 Mar 2022
Trouble-Shooting
1. General
This table explains how to troubleshoot the GDU 620 display. If you find the trouble in column 1, do
the repair given in column 3.
Trouble Possible Cause Repair
Unit does not power up - blank
screen.
Improper wiring; circuit breaker
open.
Unit intensity turned down.
Make sure that the power is
properly wired to the GDU 620
and the circuit breaker is
closed.
Make sure that the unit is not in
manual intensity control mode
with the intensity turned down.
All expected configuration
pages are not displayed.
An installer unlock card is not
inserted into the GDU 620.
Insert the installer unlock card
P/N 010-00769-60 into the
bottom slot of the GDU 620
and cycle power.
The GDC OAT probe type
shows up as UNKNOWN.
The RS-232 connection to the
GDC 74A is not working.
Make sure that the GDC 74A
RS-232 connection to the GDU
is properly wired, and that the
GDC (ADC) 74A circuit
breaker is closed.
When loading software, the
LRU software is not being
displayed on the SOFTWARE
UPLOAD page.
The software loader card is
installed in the bottom slot of
the GDU 620.
The software loader card
contains no information.
Insert the loader card in the top
slot and cycle power to the
GDU.
Repeat the process for making
the software loader card .
Configuration errors are
displayed on power-up, before
the GDU enters normal mode.
The configuration module has
not been updated.
Update the configuration
module.
Data is not being received from
an ARINC 429 device. (valid
data is being received on the
429 input port as shown on the
GDU 620 PORT
MONITORING page)
ARINC 429 bus hi and low are
swapped.
Wrong device is connected to
port on GDU 620.
Verify wiring.
Use correct ports.