Philips EM5.3A P Service Manual page 20

EN 20 5. EM5.3A P/M AA
5.8.6 Standby Supply
The simplest way is to replace the components of the Standby
Supply with repair kit 3122 785 90460.
5.8.7 Line Deflection
The simplest way is to replace the components of the Line
Deflection circuitry with repair kit 3122 785 90330.
5.8.8 Frame Deflection
Caution: When the Frame Deflection circuitry is suspected,
one must be careful. Because there is a DC-voltage on the
frame deflection, the beam current could damage the CRT
neck, leading to a defective CRT.
Table 5-4 Repair Tips
Phenomenon
No picture, no LED.
No picture, no LED.
No picture, LED blinking at 3 Hz. Set is in protection due to various
No picture, LED blinking with
code 6-6-6 or 18-18-18.
No picture, LED blinking with
code 1-1-1.
No picture, no sound. Set is
making audible squeaking sound
No picture, no sound. Power LED
works fine
No RC-reception. LED does not
echo RC-commands.
Relay (degaussing) is not
audible, when set is switched
from 'off' or 'standby' to 'on'.
Picture is rotated.
Picture is continuously switching
'off' and 'on', showing heavy
'switch' spots (set does not go
into protection).
Picture is not sharp.
Picture is not synchronised.
Picture is distorted.
No menu, no OSD.
How to measure if soldering
connections of a BGA are OK
How to measure on other IC's
Service Modes, Error Codes, and Fault Finding
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Possible Cause
Standby Supply defective.
Bad connection of SSB in SIMM-
connector.
causes. For error codes see error-
code list.
2
No communication on slow I C- or
2
fast I C-bus.
2
No communication on NVM- I C bus
to the uP.
Supply is possibly in hiccup-mode,
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which is audible via a squeaking
supply transformer.
Supply does not work correctly.
uP circuitry or RC-receiver is
defective.
uP is not working correctly.When pin
115 is low, the degaussing must be
activated.
Rotation circuitry on diagram A5, or
related supply to it, malfunctions.
200 V is missing on CRT panel.
Focus is possibly mis-aligned or
SCAVEM-circuitry does not work
correctly.
The sync is derived in the HIP from
x-tal 1305 and/or 1308.
Check video-path in Service Default
Mode.
Probably a defective uP.
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To prevent this from happening, you must:
1. Interrupt the resistors 3403 and 3404 on the CRT panel
(diagram F1), in order to remove the "filament" voltage
from the tube (no beam current, so no chance of destroying
the CRT).
2. Interrupt resistor 3403 on the LSP (diagram A4) to disable
the "SUP-ENABLE" line.
3. Measure with a multi-meter, or better with a oscilloscope,
the functionality of the Frame stage.
4. After you have found the cause, exchange the defective
component (e.g. TDA8177), and re-solder the interrupted
resistors.
Repair tip
Measure circuitry (see diagram A2). Start at test-point A19.
When the Mains switch is 'on', this voltage must always be available
In case of a bad connection, it can happen that there is no picture, and that the Standby LED is not
controllable. Re-place the SSB.
You have no picture, so:
- Read the error buffer via ComPair (error buffer is accessible when set is in protection, compare-
file will guide you to this)
- Read the blinking LED information via standard remote command <mute>06250X<ok>
- Or you read the error code sequence via standard remote command <mute>062500<ok>.
When you have found the error, check the circuitry related to the supply voltage and I
communication or the circuitry that triggers the protection.
As processor cannot communicate with one of the 2 busses it the standby-led spontaneously starts
blinking 6-6-6... or 18-18-18... If in the error buffer somewhere is an error 6 or 18, these will have
the highest priority starting the mentioned blinking. Measure dependent of the error on the I
2
which device is loading the bus. (Use I C -overview)
As the uP cannot communicate with the NVM I
when there is no access to the NVM, a lot of picture setting can go wrong.
Possible causes:
- V is shorted (caused by short circuited line transistor 7421), or
BAT
- Sound winding is shorted (amplifier is shortening the power supply lines), or
- D6514 is shorted (due to a too high V
Remove excessive load, to see what causes the failure, or check feedback circuit. See repair tip
'Main Power Supply' (supply needs a minimal load).
If e.g. V is only about 90 V, it is possible that the regulator IC (7506) is defective.
BAT
In case the set does react on a local keyboard operation, you must check the RC-receiver circuitry.
Check RESET-circuitry on diagram B5. Check the level on pin 115 when you switch the set 'on'.
Signal must be low initially and go to high after approx. 12 s.
Measure test points on diagram A5.
Probably a bad connection from LSP connector 1424 to CRT connector 1424 (diagram F), or an
interruption of the 200 V supply line (e.g. R3341 on circuit F is interrupted).
Re-align the 'focus' potmeter on the Line Output Transformer, or check the SCAVEM circuitry on
the CRT-panel (diagram F). It is also possible that the DAF circuitry is defective (see diagram I).
Check the Vdc values.
Maybe the crystals 1305 and/or 1308 are making a bad contact.
Investigate whether there is an error code present in the error buffer. In case there is one, check
2
the I C -bus and/or supply lines (see overview supply lines).
Measure and check signal path Tuner-HIP-PICNIC-HOP-RGB amplifier.In case it is a geometry
issue, check on diagram A4 opto-coupler 7482, Opamps 7440/7450 and the Frame circuitry
alignments or a possible corrupted NVM (7011) on diagram B5.
Measure test points B61to B64 on diagram B5.
For most BGA's the pins/balls are ESD protected via diodes to ground, it is possible to measure
these diodes with a multi-meter. Overload means no or bad connection.
It is advisable to measure both on the pins itself and the solder pads on the PWB. This to find
possible solder faults.
2
C bus, it spontaneously starts blinking 1-1-1. Note:
).
BAT
2
C-
2
C-bus