SOFTWARE PROTECTIONS
Most of the protections and errors use either the stand-by microprocessor or the VIPER controller as detection device. Since in these cases, checking of observers, polling of ADCs, 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, +5V,+8V6, +1.2V, +2.5V and +3.3V.
Protections
related to breakdown of the safety check mechanism. E.g. since a lot of protection detections are
done by means of the VIPER, failing of the VIPER communication will have to
initiate a protection mode since safety cannot be guaranteed anymore.PROTECTIONS DURING STARY-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.
HARDWARE PROTECTIONS
There is one hardware protection in this chassis: “Audio DC Protection”. This protection occurs when there is a DC voltage on the speakers. In that case the main supply is switched "OFF", but the stand-by supply is still working. In case of LCD supplies, the 12V supply will drop. This will be detected by the stand-by processor, which will start blinking the 12 V error (error 12).
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).
FAULT FINDING
Symptom:
FAULT FINDING
Symptom:
+1V2,
+2V5, and +3V3 not present (even for a short while ~10ms).
- Check 12V availability (fuse 1U01, resistor 3U22, power MOSFETs) and enable signal ENABLE-1V2 (active low).
- Check the voltage on pin 9 (1.5 V).
- Check for +1V2 output voltage short-circuit to GND that can generate pulsed over-currents 7-10 A through coil 5U03.
- Check the over-current detection circuit (2U12 or 3U97 interrupted).
Symptom:
+1V2
present for about 100 ms. Supplies +2V5 and +3V3 not rising.
- Check the ENABLE-3V3 signal (active "low").
- Check the voltage on pin 8 (1.5 V).
- Check the under-voltage detection circuit (the voltage on collector of transistor 7U10-1 should be less than 0.8 V).
- Check for output voltages short-circuits to GND (+3V3,+2V5 and +2V5D) that generate pulsed over-currents of 7-10 A through coil 5U00.
- Check the over-current detection circuit (2U18 or 3U83 interrupted).
Symptom:
+1V2
OK, but +2V5 and +3V3 present for about 100 ms.
Cause: The
SUPPLY-FAULT line stays "low" even though the +3V3 and +1V2 is
available. The Stand-by Processor is detecting that and switches all supply
voltages "OFF".
- Check the drop voltage across resistor 3U22 (this could be too high)
- Check if the +1V2 or +3V3 are higher than their normal values. This can be due to defective DC feedback of the respective DC/DC converter (3U18 or 3UA7).
Symptom:
+1V2,
+2V5, and +3V3 look okay, except the ripple voltage is increased (audible noise
can come from the filtering coils 5U00 or 5U03).
Cause: Instability
of the frequency and/or duty cycle of one or both DC/DC converters.
- Check resistor 3U06, the decoupling capacitors, the AC feedback circuits (2U20 + 2U21 + 3U14 + 3U15 for +1V2 or 2U19 + 2U85 + 3U12 + 3U13 for +3V3), the compensation capacitors 2U09, 2U10, 2U23 and 2U73, and IC 7U00.
If
fuse 1U01 is broken, this usually means a pair of defective power MOSFETs (7U01
or 7U03). Item 7U00 should be replaced as well in this case.
SOFTWARE UPGRADING
It is
possible for
the user to upgrade the main software via the USB port. This allows
replacement of a software image in a standalone set, without the need of an
E-JTAG debugger.
Important: When
the NAND-Flash must be replaced, a new SSB must be ordered, due to the presence
of the security keys.
Perform
the following actions after SSB replacement:
- Set the correct option codes (see sticker inside the TV).
- Update the TV software (see chapter 3 for instructions).
- Perform the alignments as described in chapter 8.
- Check in CSM menu 5 if the HDMI and POD keys are valid.
MAIN SOFTWARE UPGRADE
The
software image resides in the NAND-Flash, and is formatted. Executables are stored as files in a file
system. The boot loader (uBTM) will load the USB Download Application in
partition 0 (USB drivers, bootscript, etc.). This application makes it then
possible to upgrade the main software via USB. Installing
"Partition 0" software is possible via an external EJTAG tool, but
also in a special way with the USB stick.
- Partition 1 (Customer)
To do a
main software upgrade (partition 1) via USB, the set must be operational, and
the "Partition 0" files for the VIPER must be installed in the NAND-Flash!
The new
software can be uploaded to the TV by using a portable memory device or USB
storage compliant devices (e.g. USB memory stick). You can download the new
software from the Philips website to your PC.
- Partition 0 (Service)
If the "Partition 0" software is corrupted, the
software needs to be re-installed.
To
upgrade this “USB download application” (partition 0 except the bootblock),
insert an USB stick with the correct software, but press the “red” button on
the remote control (in ”TV” mode) when it is asked via the on screen text.
- Caution:
- The USB download application will now erase both partitions (except the boot block), so you need to reload the main SW after upgrading the USB download application. As long as this is not done, the USB download application will start when the set is switched “ON”.
- When something goes wrong during the progress of this method (e.g. voltage dip or corrupted software file), the set will not start up, and can only be recovered via the EJTAG tool.
MANUAL START OF MAIN SOFTWARE UPGRADE APPLICATION
Normally,
the software upgrading procedure will start automatically, when a memory device
with the correct software is inserted, but in case this does not work, it is
possible to force the TV into the software upgrade application. To do so:
- Disconnect the TV from the Mains/AC Power.
- Press the “OK” button on a Philips DVD RC-6 remote control (it is also possible to use the TV remote in "DVD" mode).
- Keep the “OK” button pressed while connecting the TV to the Mains/AC Power.
- The software upgrade application will start.
- When a memory device with upgrade software is connected, the upgrade process will start.
STANDBY SOFTWARE UPGRADE
It will
be possible to upgrade the Stand-by software via a PC and the ComPair
interface. Check paragraph "ComPair" on how to connect the interface.
To upgrade the Stand-by software, use the following steps:
- Disconnect the TV from the Mains/AC Power.
- Short circuit the SPI pins [2] on the SSB. They are located outside the shielding.
- Keep the SPI pins shorted while connecting the TV to the Mains/AC Power.
- Release the short circuit after approx. two seconds.
- Start up HyperTerminal (can be found in every Windows application via Programs -> Accessories -> Communications -> HyperTerminal. Use the following settings:
COM1
Bits
per second = 38400
Data
bits = 8
Parity
= none
Stop
bits = 1
Flow control = Xon / Xoff
Press
“Shift U” on your PC keyboard. You should now see the following info:
PNX2015
Loader V1.0
19-09-2003
DEVID=0x05
Erasing
MCSUM=0x0000
=- If you do not see the above info, restart the above procedure, and check your HyperTerminal settings and the connections between PC and TV.
- Via “Transfer” -> “Send text file ...”, you can send the proper upgrade file to the TV. This file will be distributed via the Service Organization.
- After successful programming, you must see the following.
info:
DCSUM=0xECB3
:Ok
MCSUM=0xECB3
Programming
PCSUM=0xECB3
Finished.
- If you do not see this info, restart the complete procedure.
- Close HyperTerminal.
- Disconnect and connect Mains/AC Power again.
