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EN 30
5.
EM5A NTSC
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-com-
mands.
Relay (degaussing) is not au-
dible when set is switched
from "off" or "standby" to
"on."
No sound, only picture.
No sound at headphone out-
put.
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 synchronized.
Picture is distorted.
Service Modes, Error Codes and Fault Finding
Possible Cause
Repair tip
Standby Supply defective.
Measure circuitry (see diagram A2). Start at test point A19.
When the set is connected to the power supply, this voltage must always be
available
Bad connection of SSB in
If there is a bad connection, there may be no picture, and the Standby LED
SIMM-connector.
may not be controllable. Replace the SSB.
Set is in protection due to
You have no picture, so:
various causes. For error
Read the error buffer via ComPair (error buffer is accessible when set is in pro-
codes see error code list.
tection, ComPair will guide you to this)
Read the blinking LED information via standard remote command
<mute>06250X<ok>
Or 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 volt-
age and I
No communication on slow
If processor cannot communicate with one of the 2 busses, the standby-LED
2
2
I
C- or fast I
C-bus.
starts blinking 6-6-6... or 18-18-18....
If error 6 or 18 is in the error buffer, these have the highest priority in starting
the blinking.
Depending on the error, measure to determine which device is loading the I
bus. (Use I
No communication on NVM-
Since the µP cannot communicate with the NVM I
2
I
C bus to the µP.
starts blinking 1-1-1. Note: when there is no access to the NVM, many picture
settings can go wrong.
Supply is possibly in hiccup-
Possible causes:
mode, which is audible via a
VBAT is shorted (caused by short circuited line transistor 7421), or
squeaking supply transform-
Sound winding is shorted (amplifier is shorting the power supply lines), or
er.
Remove excessive load, to see what causes the failure, or check feedback cir-
cuit. See repair tip "Main Power Supply" (supply needs a minimal load).
Supply does not work cor-
If, for example, VBAT is only about 90 V, it is possible that the regulator IC
rectly.
(7506) is defective.
µP circuitry or RC-receiver is
If the set reacts to a local keyboard operation, you must check the RC-receiver
defective.
circuitry (diagram E).
µP is not working correct-
Check RESET-circuitry on diagram B5. Check the level on pin 115 when you
ly.When pin 115 is low, the
switch the set "on." Signal must initially be low and go to high after approx. 12s.
degaussing must be activat-
ed.
Measure A7/A8 on diagram
In ComPair, a beep test can determine where the signal stops (use loudspeak-
A1. Possibly the audio ampli-
ers or headphone).
fier is defective (but not
Possible cause is also the 'PROT1' protection (see diagram. A6). This is a
shorted), or the 'sound ena-
loudspeaker DC protection, which the µP cannot sense. Via circuitry 7701/
ble' line is high (diagram A5).
7707, this signal can put audio amplifiers 7700 and 7702 in standby mode (tri-
Also measure the audio sig-
state input). Warning: Find out which amplifier is causing the problem, be-
nal path (HIP-MSP-Switch
cause it is possible that the other one is OK.
ICs-Amplifier).
HP amplifier (7681) on dia-
Measure pin 3 input left and pin 1 output left; repeat this for pin 3 (input right)
gram B10, or the supply to it,
and pin 7 (output right), and the supply line (+8V_AUD) on diagram B10.
is malfunctioning.
Rotation circuitry on diagram
Measure test points A52 and A53 on diagram A5.
A5, or supply related to it, is
malfunctioning.
200 V is missing on CRT
Probably a bad connection from LSP connector 1424 to CRT connector 1224
panel.
(diagram F1), or an interruption of the 200 V supply line (for example, R3341
on circuit F1 is interrupted).
Focus is possibly misaligned,
Realign the focus potmeter on the Line Output Transformer, or check the
or SCAVEM-circuitry does
SCAVEM circuitry on the CRT panel (diagram F2). It is also possible that the
not work correctly.
DAF circuitry is defective (see diagram I). Check the Vdc values.
The sync is derived in the
The crystal(s) 1305 and/or 1308 may not be making good contact.
HIP from xtal 1305 and/or
1308.
Check video path in Service
Determine whether there is an error code present in the error buffer. If one is
Default Mode.
present, check the I
view).Measure and check signal path Tuner-HIP-PICNIC-HOP-RGB amplifier.
If it is a geometry issue, check opto-coupler 7482 on diagram A4, OpAmps
7440/7450 and the Frame circuitry alignments, or a possible corrupted NVM
(7011) on diagram B5.
2
C-communication or the circuitry that triggers the protection.
2
C -overview)
2
C-bus and/or supply lines (see supply lines over-
2
C-
2
C bus, it spontaneously
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