D21m System
D21m Modules 6-3Date printed: 25.09.07
LEDs: PHANTOM 1...4 For each channel a yellow LED indicates if the pantom supply is on.
SIGNAL 1...4 For each channel a green LED indicates if input signal is present; its bright-
ness is a rough indication of the signal level.
Alignment: RA1...4 Please note that the input level trimmer potentiometers are factory-set. They
need to be adjusted only after havin
g repaired the card.
Select 15
dBu input sensitivity. Feed an analog signal with a level of +6 dBu
to one of the analog inputs. Measure the digital output level either on the
MADI output or, after routing through the core, on one of the AES/EBU
outputs. Adjust the level with the corresponding FINE ADJUST trimmer
potentiometer to –9 dB
FS
.
Connector Pin Assignment: (25-pin D-type, female)
Pin Signal Pin Signal
1 CH 4 split out + 14 CH 4 split out –
2 CH 4 split out GND 15 CH 3 split out +
3 CH 3 split out – 16 CH 3 split out GND
4 CH 2 split out + 17 CH 2 split out –
5 CH 2 split out GND 18 CH 1 split out +
6 CH 1 split out – 19 CH 1 split out GND
7 CH 4 in + 20 CH 4 in –
8 CH 4 in GND 21 CH 3 in +
9 CH 3 in – 22 CH 3 in GND
10 CH 2 in + 23 CH 2 in –
11 CH 2 in GND 24 CH 1 in +
12 CH 1 in – 25 CH 1 in GND
13 n.c.
Important! If wired correctly, the microphones are isolated from the D21m chassis. The
circuit inside the microphone takes its supply from pins 2 and 3 (+ and –) for
the positive, and from pin 1 (GND) for the negative reference. If a patch bay
is implemented, GND (pin 1 on XLR connector) of each microphone input
must be connected to its corresponding GND pin, but not to the chassis. If
chassis instead of GND is used as negative reference for a microphone, it can
occur that the GND net of the D21m is pulled towards –48 V. This causes the
HD link receivers not to work correctly or to be damaged, depending on the
type and number of microphones connected.
As a workaround, GND and chassis may be connected inside the D21m frame.
In cases where currents fl ow between the chassis nets of multiple devices, the
analog signals can degrade in quality (e.g. perceivable as hum).
RA1
RA2
RA3
RA4
RA1...4: Factory Setting (Level Fine-Adjustment)
1
Solder/Crimp View
(or Socket View)
13
25
14
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