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OPTIMOD-FM 2200 MAINTENANCE
4-1
Section 4
Maintenance
page contents
4-2 Routine Maintenance
4-3 Getting Inside the Chassis
4-7 In-System Testing ("Proof of Performance")
4-8 Monophonic Performance Verification
4-10 Stereo Performance Verification
4-16 Field Audit of Performance
4-18 Test Power Supplies (optional)
4-22 Test Stereo Baseband Encoder
4-26 Figure 4-1: Separation Scope Trace
4-27 Field Alignment
4-28 Prepare the Unit
4-28 System Default Settings
4-29 Calibrate and Test Analog Input/Output Circuitry
4-29 Return OPTIMOD-FM to Service
CAUTION
The installation and servicing instructions in this manual are for
use by qualified personnel only. To avoid electric shock do not
perform any servicing other than that contained in the Operating
Instructions unless you are qualified to do so. Refer all servicing
to qualified service personnel.
4-2 MAINTENANCE OPTIMOD-FM 2200
page
Routine Maintenance
The 2200 OPTIMOD-FM Audio Processor uses highly stable analog and digital circuitry
throughout. Recommended routine maintenance is minimal.
1. Periodically check audio level and gain reduction meter readings.
Become familiar with normal audio level meter readings, and with the normal perform-
ance of the G/R metering. If any meter reading is abnormal, see Section 5 for trou-
bleshooting information.
2. Listen to the 2200's output.
A good ear will pick up many faults. Familiarize yourself with the "sound" of the 2200
as you have set it up, and be sensitive to changes or deteriorations. But if problems arise,
please don't jump to the conclusion that the 2200 is at fault. The troubleshooting
information in Section 5 will help you determine if the problem is with OPTIMOD-FM
or is somewhere else in the station's equipment.
3. Periodically check for corrosion.
Particularly in humid or salt-spray environments, check for corrosion at the input and
output connectors and at those places where the 2200 chassis contacts the rack.
4. Periodically check for loss of grounding.
Check for loss of grounding due to corrosion or loosening of rack mounting screws.
5. Clean the front panel when it gets soiled.
Wash the front panel with a mild household detergent and a damp cloth. Stronger
solvents should not be used because they may damage plastic parts, paint, or the
silk-screened lettering (99% isopropyl alcohol can be safely used).
OPTIMOD-FM 2200 MAINTENANCE
4-3
Getting Inside the Chassis
1. Removing the Top Cover.
To access the main board, power supply board or display assembly, you must remove
the top cover.
A Disconnect the 2200 and remove it from the rack.
Be sure power is disconnected before removing the cover.
WARNING: Hazardous voltage is exposed with the unit open and the
power ON.
B Set the unit upright on a padded surface with the front panel facing you.
C Remove all twenty screws holding the top cover in place, and lift the top cover off.
Use a #1 Phillips screwdriver.
2. Removing the Display Assembly.
Note: You will need to complete this step if you intend to remove the main board.
A Gently pull off the front panel control knob.
B Remove backlight power connector
C Detach the four ribbon cables that connect the display board to the main board and
power supply board.
a) First, identify the four cables:
A larger white flat cable connecting to jumper J200 on the main board;
A gray ribbon cable connecting to a DIP header at jumper J203 on the
main board.
A smaller white flat cable connecting the display assembly to the
power supply at jumper J202.
A two-wire cable connecting the display assembly to the power supply
at jumper J201.
b) Gently lift each cable up from where it connects to its jumper, so that
the jumper pins unseat without bending or breaking. (If present, you
must first remove the retainer clip from the DIP header at J203.)
D Remove the four nuts that connect the display board to the main chassis.
Use a 1/4" long shafted nut driver or a flexible shaft nut driver.
E Grasp the edges of the front panel, pull slightly forward, and, while holding the panel
vertical, guide it forward.
4-4 MAINTENANCE OPTIMOD-FM 2200
3. Removing the Main Board.
A If you have not done so yet, remove the top cover (Step 1) and remove the display
assembly (Step 2).
B Remove the display board's metal shielding; this was left in place when the display
board was detached.
C Remove the two hex nuts holding each composite output connector to the chassis,
using a 3/16" hex nut driver.
D Remove the two hex nuts holding the Remote Interface connector to the chassis,
using a 3/16" hex nut driver.
E Detach all 4 XLR connectors (or 6 with Model 2200-D), using a jeweler's screw-
driver; engage the locking mechanism and turn counterclockwise until the XLR is
no longer attached.
F Remove the two ribbon cables that connect the power supply to the main board at
jumpers J900 and J901. (If present, you must first remove the black retainer clips.)
G Remove the four #1 Phillips screws that connect the main board to the chassis.
H Carefully pull the main board forward to clear XLRs from their housing and then out
of the chassis.
4. Removing the Power Supply Board.
A If you have not done so yet, remove the top cover (Step 1).
B If you have not done so yet, remove the ribbon cables that connect the display
assembly to the power supply board (at jumpers J201 and J202), as well as the two
cables that connect the main board to the power supply (at jumpers J900 and J901).
C Remove the twelve #1 Phillips screws holding the heat sink to the side of the chassis
-- note that some have nuts and some are tapped -- and remove heat sink.
D Remove the two Phillips screws that hold the IEC connector to the chassis.
E Remove the four bolts that hold the transformer; retain the four star washers and
eight plastic insulators.
F Remove the three Phillips screws holding the power supply board to the main
chassis.
G Remove the nut and star washer from the ground wire with a 1/4" nut driver.
H Carefully lift the power supply board up.
OPTIMOD-FM 2200 MAINTENANCE
4-5
5. Reattaching the Power Supply Board.
A Replace the two Phillips screws that hold the IEC connector.
B Replace the twelve #1 Phillips screws that hold the heat sink to the side of the chassis.
C Set power supply board into main chassis, so that it aligns with its mounting holes.
D Replace the ground wire nut.
E Replace the three Phillips screws that hold the power supply board to the main
chassis.
F Replace the four bolts that hold the transformer; use the starwashers and plastic
insulators.
G If the main board is installed, reattach the two ribbon cables that connect the main
board to the power supply.
6. Replacing the Main Board.
A Set the main board into the main chassis, so that it aligns with its mounting holes.
B Reattach all 4 XLR connectors (or 6 with Model 2200-D), using a jeweler's
screwdriver.
C Replace the two hex nuts that hold the Remote Interface connector to the chassis,
using a 3/16" hex nut driver.
D Replace the two hex nuts that hold each Composite Output connector to the chassis,
using a 9/16" hex nut driver.
E Replace the four #1 Phillips screws that connect the main board to the chassis.
F If the power supply board is installed, reattach the two ribbon cables that connect the
main board to the power supply.
4-6 MAINTENANCE OPTIMOD-FM 2200
7. Replacing the Display Board.
A Reattach the display board's metal shielding to the main chassis.
B Set the display assembly in place so that it aligns with its mounting holes.
C Replace the four nuts that connect the display board to the main chassis.
Use a 1/4" long shafted nut driver or a flexible shaft nut driver.
D Replace the four ribbon cables that connect the display board to the main board and
power supply board.
E Replace the front panel control knob.
8. Replacing the Top Cover.
A Place top on unit and reattach the twenty Phillips screws. (Be careful not to pinch the
ribbon cables or the two-wire backlight power connector.)
OPTIMOD-FM 2200 MAINTENANCE
4-7
In-System Testing ("Proof of Performance")
The FCC (Federal Communications Commission -- U.S.A.) no longer requires periodic
Proof of Performance measurements for FM stations. However, many stations will still wish
to make periodic equipment performance measurements to ensure that their transmission
system is working correctly and that they comply with all government regulations. The text
below provides the general information that is needed to perform measurements verifying
the performance of a transmission system including the 2200. Instructions for bench-top
verification of 2200 performance outside of the transmission system are found below in
Field Audit of Performance starting on page 4-16.
These instructions are written with the assumption that the analog inputs and outputs are
used. If the 2200-D's digital I/O is used instead, follow the procedures below by analogy --
you will have to supply digitized test tones.
The NAB Broadcast and Audio System Test CD provides a good source of digitally-
generated test tones on compact disc. They supply tones at a 44.1kHz sampling rate that
can be applied to the 2200-D's AES/EBU input. This test CD is available from:
NAB Services
1771 N Street N.W.
Washington, D.C. 20036, U.S.A.
order: (1) (800) 368-5644
Required Equipment: