G A L A X Y ® A U R O U R A C O N F I G U R A T I O N A N D S Y S T E M I N T E G R A T I O N G U I D E
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Section 4 Troubleshooting Guide
Rack Mounting:
On many of the chassis we’ve used, there are problems
associated with the weight of the unit when used in a Rack configuration. The
rack mounting system typically starts at the chassis itself, with a series of
tangs which are punched out of the metal. In a lot of cases, these can become
bent, making it difficult to attach the rails – you can bend the tangs out, but it
should only be by enough to get the rail on – overbending it will cause the rail
to jam when the unit is rack-mounted. The slides which attach to the sides
have to go on particular sides and with a particular orientation. Currently, on
chassis we’ve used, it isn’t possible to install the slides with an incorrect
orientation unless they are on the wrong sides. On the front of the chassis are
a pair of rack ears. These ears are held to the chassis using screws which go
into the chassis by an amount less than 1/16”, and are not made to take any
weight whatsoever.
MTP:
The left ear on most chassis, also contains electrical connections
between an MTP (Mapping/Test Panel) on the ear, which turns on or resets
the power, and provides LED status information, and connects to the
motherboard. On the front of the ear is a handle – most are connected with
sub-standard screws which only extend into the handle by 1/8” – again, these
can not take any weight. The MTP electrical connection is much more complex
than it looks. Inside the rack ear is a small circuit board – on this board is a
connector which is attached to a flat ribbon cable. The connector can be
opened and ribbon cable removed, but it is very difficult to reassemble. The
ribbon cable passes through a hole in the chassis (and can be easily damaged
by metal cutting into the cable), to another circuit board inside the chassis.
This inner circuit board also has a connector for the ribbon cable which can be
opened/closed, then it is attached to another removable cable which goes to
the MTP connector on the motherboard. The desktop chassis also contains an
MTP, but is it not as delicate, easy to break, or as complex as the ones on the
Rack enclosures.
Chassis Construction/Bulkheads/Air Baffles:
Many of the chassis used
aren’t just a simple piece of metal bent into the shape of a PC. The rack-mount
chassis, for example, are no less than 3 layers of metal at almost any given
spot at the front, 2 at the bottom where the motherboard is, and sometimes 2
at the rear. It is possible to disassemble these layers, however the correct
tools and replacement parts must be used. Most chassis have an inner
bulkhead, separating the front of the chassis from the rear of the chassis,
typically holding the central fans. The bulkhead is removable to allow easier
access to many of the components. Finally Air Baffles: These provide directed
cooling at specific components, and some provide protection for more delicate
internal components. On some of the rack chassis, there is an air baffle
covering the DC power distribution board. This is strictly to provide airflow
while protecting the delicate components on that board. It can be removed if
necessary, but should be replaced when done. Finally, there is usually a main
air baffle in the system, directing air from the fans across the CPU and RAM. If
