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5.2.2
No Video on One Monitor
Assuming that the monitor operation has been checked by applying a direct signal, the
fault could be in a number of modules. For a small system only one RD-85 and one RD-
200 are in the video circuit for the monitor channel. It is critical that the block diagram is
used to locate the signal path and modules related to the faulty channel.
The first step would be to make a normal keyboard selection for this monitor. While
doing this, watch the LED indicators on the modules and check that a yellow LED
flashes on the subrack RD-105, RD-85 and the RD-200. If they do, then it is reasonable
to assume that the communication to these modules is operating.
There are now two ways to determine the faulty module. The first is to swap one at a
time with modules from an operating channel. The second is to monitor the video test
output on the front of each module with the test monitor.
If the data indicator LEDs do not flash on one of the modules, then it would be worth
swapping this with another channel to verify its operation. Press the Reset button on the
upper front edge of the sub-rack controller (RD105) and allow a few seconds for the
system to warm boot before continuing with the tests.
5.2.3
No Text on Monitor or Monitors
Very similar to test as for the above. Make a normal action and check that the data LEDs
flash. If text is lost on one monitor, only then swap the module with another and reset. If
there is no text, or no text update on any monitor and all the RD-200 modules are in one
subrack, then check that the data LED is flashing on the RD-105 module when
selections are made from a keyboard logged to the faulty monitor. If not, then there may
be a communication problem with the control computer or the subrack RD-105 module.
Use an RS-232 tester or PATCH232 to check data flow.
5.2.4
No Operation from a Keyboard
The symptoms of this fault can occur because a keyboard is logged off. Check this first.
Check that the cable from the keyboard has not been damaged by stretching or
excessive flexing and that the keyboard has power. If the cable and connections seem
okay, then insert an RS-232 tester and check that the LEDs flash when a keyboard
action is made. If the LEDs do flash, then it may be necessary to swap with another
keyboard to check the input port to the computer (do not forget to set the correct
keyboard ID code). Alternatively, use PATCH232 to verify that the data from the
keyboard is of good quality. Always check the transmission speed for keyboards
especially if it is transferred across a link such as microwave or fiber optic. Use of in-built
test modes as detailed on page (5.8) may be helpful.
Rev. C
5-2
HMXMU01018
10/06
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