Philips M3001A Service Manual page 223

Using Service Mode
Print out the Status Log in which the error is reported.
•
To ensure the fault is not a single (sporadic) fault, you should rerun the coldstart sequence
(including clearing the Status Logs).
• If a fatal error is again reported, either the System Board or the Server should be replaced.
Please include the printed Status Log with the exchanged parts.
Display Test
This test is a non-destructive, visual test of the SGRAM video memory. From left to right, top
to bottom a small square consisting of colored bars moves over the whole screen during
approximately 30 seconds. During this test, the memory content of the video display
(consisting of small blocks of memory) is read into other memory and stored. Then the
memory blocks are filled with a colored bar pattern, cleared again, and then recovered with
the previously stored data. The tested display then reverts to the pre-test state.
The test continues until either it is switched off or Service Mode is exited.
Success—The test is passed if the display has reverted to the pre-test state once the test has
passed over the whole screen once. (Be aware that numerics are updated also during a
running display test. This should not be considered a fault.
Failure—The test is failed if the display has not reverted to the pre-test state once the test has
passed over the whole screen once. If the test fails, repeat the test to make sure that it is not a
single (sporadic) fault. If it fails again, exchange the System Board.
The advantage of this test compared to the SGRAM video memory test executed in the
coldstart test is that the patient database is not erased and the active default set is not reset to
user defaults.
Backlight Test
The cumulative time the backlight has been operating is shown. When replacing backlight
tubes, this counter must be reset. A reset of the backlight time must be confirmed.
If the backlight tubes have been on for an estimated time of typically 25 000 hours,
brightness might be reduced by about half and the tubes should be replaced. Since the
reduction of effective brightness depends on a number of factors, the decision to replace the
tubes should be determined on a case by case basis rather than the total number of operating
hours. Examples of factors that contribute to reduced backlight brightness are as follows:
• Cumulative operating hours.
• Operating-interval time or user-set brightness level.
Troubleshooting the Instrument 207