Philips 32PFL3403D/85 Service Manual page 26

EN 26 5. LC8.1U LA
5.6 Fault Finding and Repair Tips
Notes:
• It is assumed that the components are mounted correctly
with correct values and no bad solder joints.
• Before any fault finding actions, check if the correct
options are set.
5.6.1 Software Protections
Most of the protections and errors use either the stand-by or the
micro processor as detection device. Since in these cases,
checking of observers, polling of ADCs, and filtering of input
values are all heavily software based, these protections are
referred to as software protections.
There are several types of software related protections, solving
a variety of fault conditions:
• Protections related to supplies: check of the 12V.
• Protections related to breakdown of the safety check
mechanism. E.g. since the protection detections are done
by means of software, failing of the software will have to
initiate a protection mode since safety cannot be
guaranteed any more.
Remark on the Supply Errors
The detection of a supply dip or supply loss during the normal
playing of the set does not lead to a protection, but to a cold
reboot of the set. If the supply is still missing after the reboot,
the TV will go to protection.
Protections during Start-up
During TV start-up, some voltages and IC observers are
actively monitored to be able to optimize the start-up speed,
and to assure good operation of all components. If these
monitors do not respond in a defined way, this indicates a
malfunction of the system and leads to a protection.
5.6.2 Hardware Protections
The only real hardware protection in this chassis is (in case of
an audio problem) the audio protection circuit that will trigger
the uP to switch "off" the TV.
Repair Tip
• It is also possible that you have an audio DC protection
because of an interruption in one or both speakers (the DC
voltage that is still on the circuit cannot disappear through
the speakers).
Caution: (dis)connecting the speaker wires during the ON
state of the TV at high volume can damage the audio
amplifier.
5.6.3 NVM Editor
In some cases, it can be convenient if one directly can change
the NVM contents. This can be done with the "NVM Editor" in
SAM mode. With this option, single bytes can be changed.
Caution:
• Do not change these, without understanding the
function of each setting, because incorrect NVM
settings may seriously hamper the correct functioning
of the TV set!
• Always write down the existing NVM settings, before
changing the settings. This will enable you to return to the
original settings, if the new settings turn out to be incorrect.
Service Modes, Error Codes, and Fault Finding
5.6.4
5.6.5
Table 5-2 NVM editor overview
Hex Dec
Address 0x000A 10
Value 0x0000 0
Store Store?
Load Default NVM Values
It is possible to download default values automatically into the
NVM in case a blank NVM is placed or when the NVM first 20
address contents are "FF". After the default values are
downloaded, it is possible to start-up and to start aligning the
TV set. To initiate a forced default download the following
action has to be performed:
1. Switch "off" the TV set with the mains cord disconnected
from the wall outlet (it does not matter if this is from "Stand-
by" or "Off" situation).
2. Short-circuit the SDM jumpers on the SSB (keep short
circuited).
3. Press "P+" or "CH+" on the local keyboard (and keep it
pressed).
4. Reconnect the mains supply to the wall outlet.
5. Release the "P+" or "CH+" when the set is started up and
has entered SDM.
When the downloading has completed successfully, the set
should be into Stand-by, i.e. red LED on.
Alternative method:
It is also possible to upload the default values to the NVM with
ComPair in case the SW is changed, the NVM is replaced with
a new (empty) one, or when the NVM content is corrupted.
After replacing an EEPROM (or with a defective/no EEPROM),
default settings should be used to enable the set to start-up and
allow the Service Default Mode and Service Alignment Mode to
be accessed.
Display option code
Caution: In case you have replaced the SSB, always check the
display option code in SAM, even if you have picture. With a
wrong display option code it is possible that you have picture,
but that in certain conditions you have unwanted side-effects.
Description
Existing value
New value