© 2001 Wohler Technologies Inc. ALL rights reserved
23
AMP2-V2DA User Manual P/N 821539 Rev-A
Section 3: Technical Information
1) Removal of the Top Cover
Remove the top cover screws (2 along upper front panel, 2 per each side, 3 along upper rear panel). The 919126 PCB is
vertically mounted to chassis bottom just behind the front panel mounted LED driver PCB (see photo below).
2) Adjustment Pot Locations and Functions
On the 919126 PCB(s) the P2 pot adjusts the
left
(Channel A) bargraph meter and the P3 pot adjusts the
right
(Channel B)
bargraph meter. See diagrams below.
3) “0” Fine Adjustment Setup
Connect a test signal of approximately 1 kHz of the amplitude desired to give a “0” indication on the bargraph. This signal
should be connected across the balanced inputs, and should be from a balanced source.
4) Fine Adjustment of the Bargraph “0” Level
Turning each pot clockwise
increases
the
displayed
level (sensitivity) of the associated bargraph meter. For example, to set
the zero level at +7 dBu (rather than the factory default setting of +4 dBu), adjust the appropriate DIP switch for gain closest
to that desired (see page 22 for Gain Calibration settings). Feed a +7 dBu signal (see step 3) into the analog input on the rear
panel (Item H, page 16), then turn the pots
counter
-clockwise as you visually monitor the associated bargraph meter on the
front panel until the desired display setting (“0”) is achieved for the increased input level. To zero the meters for a lower input
level, you would turn the pots
clockwise
to increase the displayed level for any decreased input level.
Note:
For range setting, use the Meter Input Gain Calibration/Bargraph Display Mode DIP Switches
Level Meter Bargraph "0" (zero) Fine Adjustment
P2
pot adjusts the
left
bargraph meter.
P3
pot adjusts the
right
bargraph meter.
Turn pots
clockwise
to
increase
the display level (sensitiv-
ity) in the associated bargraph meter
R10
R12
IC5
P2
P3
Level Generator (919126) and LED Driver (919110) PCB Descriptions
Level Generator Boards (919126)
All signals are input to discrete level generator PC boards. Each level generator PC boards responsibility is to process tasks such as
Digital Signal Processing (DSP), frequency response, integration time, and VU or PPM “dot” display mode. The ADSP-2115 chip on
the each Level Generator board handles the entire processing function. During the assembly of an AMP2 Digital unit, software is
programmed and loaded to a socket chip for a specific unit in-house.
A standard factory calibration of "0" indication when input level is +4 dBV is set for the calibration level unless specified differently
by the end user. A bank of DIP switch sections is located at the rear of Level Generator boards, which can be accessed through the top
cover. A combination of DIP switch settings can be used to apply display mode (VU, PPM) and level meter gain.
LED Driver Boards (919110)
All the digital information processed from the Level Generator PC boards are transfered to the LED driver boards through a 10-pin
color coded cable. LED Driver Boards accept fixed-length word serially, and latch the outputs for the bargraph segments correspond-
ing to those bits in the received word, which are set high.
Brightness of the bargraph displays can be adjusted to a desired setting by adjusting the trimpot located on the front panel. All
bargraph displays are simultaneously adjusted with this one trimpot.
