Metric Halo Mobile I/O - Manual (Page 337)

Troubleshooting Guide
337
Finally, the Apple Cinema Display has a known issue with its backlight dimmer. If you run the Apple Cinema
Display with its backlight at anything other than full brightness, the backlight dimmer will introduce a midrange
buzz into the system ground which will appear in unbalanced interconnects (input and output) with Mobile
I/O. This issue affects other devices that connect to the computer’s system ground. The work around is to run
the display at full brightness, or use balanced interconnects.
FIRMWARE UPDATE PROBLEMS
Details on updating the firmware of Mobile I/O are available in the Updating Firmware appendix.
It is possible for firmware updates to “not take”. This appears to be related to DSP loading issues in the Mobile
I/O, other devices on the FireWire bus, and the state of the FireWire system software on the Mac. If you have
problems with updating the firmware, try the following procedure:
1. Remove all devices from the FireWire bus
2. If your Mobile I/O is using external power, disconnect the power
3. Reboot your computer
4. Attach the external power supply to the Mobile I/O while holding down the front panel Mute button;
this will boot the Mobile I/O into the safety boot firmware
5. Connect the Mobile I/O to your computer
6. Run the firmware updater
Since Mobile I/O implements safe-boot and safe firmware update, you should always be able to use this
procedure to update the firmware, even if something goes horribly wrong (like losing power during an update).
BUS POWERING MOBILE I/O
ULN-8 and LIO-8 owners:
It is not possible to power the ULN-8 or LIO-8 via FireWire bus power.
If you are bus powering the Mobile I/O, there is a possibility that you have overloaded the power rating of
the power source.
NOT ENOUGH POWER ON THE BUS
While all Macintosh computers with built-in FireWire supply bus power, some models do not provide enough
power on the bus to power Mobile I/O. If this is the case, you will generally find that the Mobile I/O will boot
on initial connection, but will then lose power or will reboot repeatedly after a short period of operation.
Newer Intel Macs have implemented an in-rush current limit circuit breaker that may trigger when powering
a Mobile I/O unit. This will prevent the computer from booting the unit, but not from powering it. So you
can use an external supply or battery to get the unit powered up and then use the computer’s bus power to
provide power to the Mobile I/O.
Some Mac models provide enough power if they are plugged into the wall, but will not provide enough power
while running on batteries. If the computer does not provide enough power, you will need to use an external
power source with Mobile I/O.
The external power supply provided with Mobile I/O is the perfect solution if you are using Mobile I/O in an
environment where ac power is available. The external power supply will actually provide power to the bus
and can be user to power other bus-powered peripherals (see other bus powered devices).
If AC power is not available, you will need to use an external battery-based power source to power Mobile
I/O. Any source that provides 9V-30V and can support 12-15W of power consumption will work well with
Mobile I/O. Check with Metric Halo for specific recommendations.