Maintenance; Model 907 Board Handling - Focal 907 User Manual

907-0601-00 Rev. C
Optical Power Budget Test
1. To verify the remote-to-console flux budget (uplink), measure the transmit power of the remote
modem by connecting the optical output directly to a calibrated optical power meter using a short,
low-loss, singlemode test jumper. (Use 50 µm core multimode jumpers if it's a multimode system.)
2. Remove the test jumper and install a variable optical attenuator (VOAT) between the remote and
console modems.
3. Adjust the VOAT until a Link LED on either one of the modules starts to flicker or go out, then reduce
the loss to the point where both link LEDs are continuously on. A stable video signal without any
streaking or "snow" is another good reference point.
4. Measure the optical power at the console modem by connecting that end of the VOAT to the optical
power meter. The difference between this value and the transmit power previously measured is an
estimate of optical power budget. A spool of fiber used with the VOAT can also be used to simulate
losses due to dispersion over long cable lengths.
5. Repeat steps 1-4 with connections reversed to verify the console-to-remote optical budget (downlink).
8.4

Maintenance

The unit requires no routine maintenance or calibration for the specified performance. Maintenance of the
units is limited to cleaning the various components using the methods described below.
Dust or dirt on the cards can be blown off using compressed air. If severe contamination of the cards should
occur, they can be removed and cleaned using distilled water. Cards must be thoroughly dried before
reapplying power.
In order to maintain optical performance, ensure the fiber optic connectors are kept clean. Use a suitable
solvent, such as reagent grade isopropyl alcohol, and a lint free tissue paper, such as Kimwipes® EX-L, to
carefully wipe any dirt off the face and barrel of the ceramic ferrules prior to making a connection.
Always replace dust caps on the Model 907 fiber optic bushings when removing connectors. If bushings are
left open, they should be cleared of dust with compressed air prior to reconnection. Fiber jumpers and pigtails
should be periodically inspected for damage, such as nicks in the jackets or excessive bends.
8.5

Model 907 Board Handling

The Model 907 system can include several densely populated Printed Circuit Board Assemblies (PCBAs).
Although these boards are all conformally coated, care must be taken while handling the boards to ensure the
PCBAs are kept clean and free from electrostatic discharge (ESD) conditions.
General Handling
Care must always be taken during the handling of PCBAs to ensure product integrity. The following guidelines
should be observed while working with PCBAs:
Always handle boards by the edges and do not touch any connector pins
Handle boards at an ESD safe workstation with a clean surface
Never lay PCB assemblies on top of one another
Ensure fibers are not crimped or moved away from their intended routes
If the assembly is set down, always place the boards bottom side down
Ensure any disconnected optical connectors are cleaned immediately prior to reconnection
Do not exceed the recommended minimum fiber bend radius, even momentarily
Focal Technologies Corp.
Model 907 Video/Data Multiplexer – User's Guide
Page 8-3