Tektronix TLA 720, Руководство по обслуживанию

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Mainframe Troubleshooting
4–44
TLA 720 Benchtop Chassis and TLA 7XM Expansion Chassis Service Manual
Expansion Mainframe Troubleshooting
Because the expansion mainframe adds a level of complexity to troubleshooting
problems, this section will concentrate on tips and tricks to aid you in trouble-
shooting expansion mainframe related problems.
If you have exhausted all of the failure symptoms and possible causes that start
on page 4–28, try some of the troubleshooting tips and tricks that follow.
There are certain signs that the expansion mainframe is not powering-on
correctly. By looking and listening to these “signs of life” you can determine if
the expansion mainframe is not powering-on because the expansion mainframe is
not receiving a signal from the expansion module.
Upon powering-on the benchtop mainframe, a signal is sent from the expansion
module in the benchtop mainframe, to the expansion module in the expansion
mainframe via the three expansion cables. If the expansion mainframe does not
receive this signal, the expansion mainframe will not be prompted to power-on.
If the power-on signal is received by the expansion mainframe the fan will start
and the lamp on the mainframe will light. Further indications that the mainframe
is receiving signals from the expansion module is that the lights on the expan-
sion module and any other installed modules will blink, indicating that signals
are being received.
If you have available a known good expansion module, perform the following
procedure:
1. Remove the suspect expansion module from the expansion mainframe. The
expansion module is a slot zero device when installed in the expansion
mainframe. First verify that the expansion module is installed in slot zero
and that the MODID switches on the back of the module are set to FF.
or,
Try swapping the expansion module from the benchtop mainframe with the
expansion module from the expansion chassis. This sometimes works
because one module is a sender while the other module is a receiver.
The single-wide expansion module requires up to 60 lbs. of insertion force to
engage it into the back plane.
Look and Listen for the
Expansion Mainframe
Power-On Sequence
Substitute a Known Good
Expansion Module