5
Service modes, error codes and protections
13
Note: The diagnose mode can not be entered if the SAM is
activated.
Compair
ComPair (Computer Aided Repair) is a service tool for Philips
Consumer Electronics products. ComPair is a further
development on the DST service remote control allowing faster
and more accurate diagnostics. ComPair has three big
advantages:
•
ComPair helps you to quickly get an understanding how to
repair the MG2.1E in short time by guiding you step by step
through the repair procedures.
•
ComPair allows very detailed diagnostics (on I
2
C level) and
is therefore capable of accurately indicating problem
areas. You do not have to know anything about I
2
C
commands yourself; ComPair takes care of this.
•
ComPair speeds up the repair time since it can
automatically communicate with the MG2.1E (when the
micro processor is working) and all repair information is
directly available. When ComPair is installed together with
the SearchMan MG2.1E electronic manual, schematics
and PCBs are only a mouse-click away.
ComPair consists of a Windows based fault finding program
and an interface box between PC and the (defective) product.
The ComPair interface box is connected to the PC via a serial
or RS232 cable. In case of the MG2.1E chassis, the ComPair
interface box and the television communicate with each other
via bi-directional infrared signal.
Figure 5-3
Figure 5-4
The ComPair fault finding program is able to determine the
problem of the defective television. ComPair can gather
diagnostic information in 2 ways:
1.
Communication to the television (automatic)
2.
Asking questions to you (manually)
ComPair combines this information with the repair information
in its database to find out how to repair the MG2.1E.
Automatic information gathering
Step-by-step start up. Under normal circumstances, a fault in
the power supply or an error during start-up will switch the
television to protection-mode. ComPair can take over the
initialisation of the television. In this way it is possible to
distinguish which part of the start-up routine (hence which
circuitry) is causing the problem.
Reading out the error buffer, ComPair can automatically read
out the contents of the entire error buffer.
Diagnosis on I
2
C level. ComPair can access the I
2
C bus of the
television without a physical connection. ComPair can send
and receive infrared commands to the micro controller of the
television. These commands are translated by the controller to
I
2
C commands and vice versa. In this way it is possible for
ComPair to communicate (read and write) to devices on the I
2
C
busses of the MG2.1E.
Manual information gathering
Automatic diagnosis is only possible if the micro controller of
the television is working correctly and only to a certain extend.
When this is not the case, ComPair will guide you through the
fault finding tree by asking you questions and showing you
examples. You can answer by clicking on a link (e.g. text or an
oscillogram) that will bring you to the next step in the
faultfinding process.
A question could be: Do you see snow? (Click on the correct
answer)
YES / NO
An example can be: Measure testpoint I7 and click on the
correct oscillogram you see on the oscilloscope
Figure 5-5
By a combination of automatic diagnostics and an interactive
question/answer procedure, ComPair will enable you to find
most problems in a fast and effective way.
Additional features
Beside fault finding, ComPair provides some additional
features like:
•
Uploading/downloading of presets
•
Managing of preset lists
•
Emulation of the Dealer Service Tool
SearchMan (electronic service manual)
When ComPair is installed in combination with SearchMan, all
schematics and PCBs will be directly available while you repair
a television if you click on a PCB or schematic link.
Example: Measure the DC voltage on C2568 (PCB/schematic)
on the small signal level.
Clicking on PCB will automatically pop-up a picture of the PCB
with the location of C2568 marked. Clicking on schematic will
86532027_003.EPS
050898
PC
VCR
I
2
C
Power
9V DC
86532027_002.EPS
050898
0.3-0.6m
20
o
10
o
I7 B7502
1V / div DC
10
µ
s / div
