Philips 28PW9528, Service Manual

Page: 31 / 134

Service Modes, Error Codes, and Fault Finding
EN 31 EM5.1E 5.
Figure 5-5 Repair tips
CL 36532017_047.eps
240403
Phenomenon Possible Cause Repair tip
No picture, no LED. Standby Supply defective. Measure circuitry (see diagram A2). Start at test-point A19.
When the Mains switch is ‘on’, this voltage must always be available
No picture, no LED. Bad connection of SSB in
SIMM-connector. 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.
No picture, LED blinking
at 3 Hz. Set is in protection due to
various causes. For error
codes see error-code list. 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
2
C-communication or the circuitry that triggers the protection.
No picture, LED blinking
with code 6-6-6 or 18-
18-18. No communication on slow
I
2
C- or fast I
2
C-bus.
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
C-bus which device is loading the bus.
(Use I
2
C -overview)
No picture, LED blinking
with code 1-1-1. No communication on NVM-
I
2
C bus to the uP.
As the uP cannot communicate with the NVM I
2
C bus, it spontaneously starts
blinking 1-1-1. Note: when there is no access to the NVM, a lot of picture
setting can go wrong.
No picture, no sound.
Set is making audible
squeaking sound Supply is possibly in hiccup-
mode, which is audible via a
squeaking supply transformer. Possible causes:
-
V
BAT
is shorted (caused by short circuited line transistor 7421), or
-
Sound winding is shorted (amplifier is shortening the power supply lines),
or
-
D6514 is shorted (due to a too high V
BAT
).
Remove excessive load, to see what causes the failure, or check feedback
circuit. See repair tip ‘Main Power Supply’ (supply needs a minimal load).
No picture, no sound.
Power LED works fine Supply does not work
correctly. If e.g. V
BAT
is only about 90 V, it is possible that the regulator IC (7506) is
defective.
No RC-reception. LED
does not echo RC-
commands. uP circuitry or RC-receiver is
defective. In case the set does react on a local keyboard operation, you must check the
RC-receiver circuitry (diagram E).
Relay (degaussing) is
not audible, when set is
switched from ‘off‘ or
‘standby’ to ‘on’. uP is not working correctly.
When pin 115 is low, the
degaussing must be
activated. 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.
Picture is rotated. Rotation circuitry on diagram
A5, or related supply to it,
malfunctions. Measure test points on diagram A5.
Picture is continuously
switching ‘off’ and ‘on’,
showing heavy ‘switch’
spots (set does not go
into protection). 200 V is missing on CRT
panel. Probably a bad connection from LSP connector 1424 to CRT connector 1424
(diagram F1), or an interruption of the 200 V supply line (e.g. R3341 on circuit
F1 is interrupted).
Picture is not sharp. Focus is possibly mis-aligned
or SCAVEM-circuitry does not
work correctly. Re-align the ‘focus’ potmeter on the Line Output Transformer, or check the
SCAVEM circuitry on the CRT-panel (diagram F2). It is also possible that the
DAF circuitry is defective (see diagram I). Check the Vdc values.
Picture is not
synchronised. The sync is derived in the HIP
from x-tal 1305 and/or 1308. Maybe the crystals 1305 and/or 1308 are making a bad contact.
Picture is distorted. Check video-path in Service
Default Mode. Investigate whether there is an error code present in the error buffer. In case
there is one, check the I
2
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.
Picture with horizontal
stripes. Pixel Plus processing is
malfunctioning Check functionality on circuitry (B3a, B3b, and B3c) of PICNIC (7713),
FALCONIC (7718, EAGLE (7724) and/or field memories (7714, 7717, 7719,
7722 and 7723.
Tip the whole Pixel Plus chipset (3 ICs + 5 Field Memories can be diagnosed
very good via ComPair.
No menu, no OSD. Probably a defective uP. Measure test points B61to B64 on diagram B5.
No NexTView (EPG). IC7012 defective or not
powered. Check circuitry around IC7012 on diagram B5.
No Teletext. IC7007 defective or not
powered. Check circuitry around IC7007 on diagram B5. Check also B61to B64 around
uP on diagram B5.
Strange switch ‘off’
behaviour TS7445 possibly defective. Check, with a multi-meter, whether transistor TS7445 is well functioning.
(diagram A3).
Various symptoms, due
to missing local supply
voltage. An interrupted fuse, NFR-
resistor or connection. When no symptom or error code leads you to a specific circuitry, use the supply
lines overview (see chapter 6), for a quick scan of all supply lines.