Philips EM5E AA Service Manual page 34

EN 34 5.
(first connect ground to measuring equipment, than measure
the gate).
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
Table 5-4 Repair tips
Phenomenon
No picture, no LED.
No picture, no LED.
No picture, red LED
blinking at 3 Hz.
No picture, red LED
blinking with code 6-6-6
or 18-18-18.
No picture, red LED
blinking with code 1-1-1.
No picture, no sound.
Set is making audible
squeaking sound
No picture, no sound.
Green LED works fine
No RC-reception. Red
LED does not echo RC-
commands.
Relay (degaussing) is
not audible, when set is
switched from 'off' or
'standby' to 'on'.
No sound, only picture. Measure A7/A8 on diagram
EM5E Service Modes, Error Codes and Fault Finding
Possible Cause
Standby Supply defective.
Bad connection of SSB in
SIMM-connector.
Set is in protection due to
various causes. For error
codes see error-code list.
No communication on slow
2 2
I C- or fast I C-bus.
No communication on NVM-
2
I C bus to the µP.
Supply is possibly in hiccup-
mode, which is audible via a
squeaking supply transformer.
Supply does not work correct-
ly.
µP circuitry or RC-receiver is
defective.
µP is not working correct-
ly.When pin 115 is low, the de-
gaussing must be activated.
A1. Possibly the audio amplifi-
er is defect (but not shorted),
or the 'sound enable' line is
high (diagram A5). Further,
measure the audio signal path
(HIP-MSP-Switch ICs-Amplifi-
er).
frame deflection, the beam current could damage the CRT
neck, leading to a defective CRT.
• Best thing to do is:
• 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).
• Interrupt resistor 3403 on the LSP (diagram A4) to disable
the 'SUP-ENABLE' line.
• Measure with a multi-meter, or better with a oscilloscope,
the functionality of the Frame stage.
• 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 protec-
tion, 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
2
the supply voltage and I C-communication or the circuitry that triggers the protec-
tion.
As processor cannot communicate with one of the 2 busses it the standby-led spon-
taneously 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 blink-
ing. Measure dependent of the error on the I
2
(Use I C -overview)
As the µP cannot communicate with the NVM I
ing 1-1-1. Note: 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 (diagram E).
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 µs.
In ComPair, a beep test can determine where the signal stops (use loudspeakers
or headphone).Possible cause is also the 'PROT1' protection (see diagram. A6).
This is a loudspeaker DC protection, which the µP cannot sense. Via circuitry 7701/
7707, this signal can put audio amplifiers 7700 and 7702 in standby mode (tri-state
input). Warning: Find out, which amplifier is causing the problem, because it is pos-
sible, that the other one is OK.
2
C-bus which device is loading the bus.
2
C bus, it spontaneously starts blink-
).
BAT