Power; Bench Test - Focal 907 User Manual

907-0601-00 Rev. C
8.2

Power

Most Model 907 cards are powered in one of two ways: through a dedicated on-board power connector or via
the PC/104 backplane from another card in the stack. Refer to the configuration drawings for the cards in your
stack for options. In general, cards are powered as follows: Model 907 motherboards obtain power through a
2 pin Molex power connector (Ground and +5 VDC), and are capable of providing power to other cards in the
stack through the backplane PC/104 interface; Model 907 expansion cards acquire power from 907
motherboards through the backplane; and Model 907 media converter cards typically access power via the
2 pin Molex connector when used as standalone cards, or via the PC/104 connector when stacked with long
pins.
All Model 907 cards require a regulated +5 VDC. The tolerance varies from card to card, but is typically ±5%
to ±10%. Current draw varies from card to card, and the total current draw for a stack (if drawn from the
motherboard) must be calculated to ensure it does not exceed the fuse rating of the motherboard.
Power inputs are typically fused with time delay thermal fuses. The user can find replacement fuse values and
part numbers in Appendix A and on the card specific configuration drawings (907-2xxx-xx series).
Power and ground leads should be 18-20 AWG and kept short to minimize voltage drop across the powering
harness from the source to the card. Installers should also ensure that if multiple cards are powered from the
same supply, all the power and ground leads are connected in parallel to share the current and minimize the
voltage drop across the wiring. If regulated +5V power supplies are not available, the 907-DC-24 PSU card
can be added to generate multiple +5V supplies from 18-30 VDC.
Note: In order to account for the start-up current required to power up the Model 907 cards, it is
recommended to use a 5V, 3A regulated power supply when using a standalone 907 card or a 5V, 6A
regulated power supply when using a Model 907 stack. Appendix C shows the power current (after
start-up) of the Model 907 cards.
8.3

Bench Test

Basic Link Operation
Basic operation of the uplink and downlink can be verified in a bench test simply by connecting fiber jumpers
between the optical access bushings. The number of jumpers and the optical attenuation required depends
on the optical configuration of the system under test. In some optical configurations, it may be required to use
5 or 10 dB optical attenuators placed between the fiber bushings on the remote modem and the bushings on
the console modem to ensure the optical receivers are not saturated. Complete a flux budget calculation for
your system, referring to the data sheet for the installed transceivers to determine whether optical attenuation
is required or not.
After power is applied to the motherboards, the power LEDs should be on. An unlit Link LED usually indicates
insufficient received optical power, typically due to excessive loss in the fiber link. Excessive loss may be
caused by poor fiber connections (contaminated bushings, damaged fiber, damaged ferrules) or excessive
fiber bends. It is good practice to carefully clean all fiber connections prior to mating them for testing.
If the basic optical link is present, there should be good video and data continuity through the multiplexer
system. A video signal is an excellent test for the system, since even relatively low rates of link errors are
easily visible on a monitor as black lines or speckles.
Focal Technologies Corp.
Model 907 Video/Data Multiplexer – User's Guide
Page 8-2