Philips 221TE4L flashing screen

[Maxmad]

Hello to the forum,


Facing a flashing panel problem with this Philips model.
Here is a video of it:

https://sendvid.com/3999k0f3

The TV seems to startup normally showing the boot logo but after that it started to flashing for some seconds until turns to total black.

Found the schematics for PS and main board on 2 different chassis.

I have already tested some voltages. Power supply board seems to works fine as it lights the panel with an external voltage to the ACT/EN pin.

About the main board. Checked the VCCK voltage must be 1.1 V to power the MT5366 micro processor. On page 29, both +5V_STB and PWR_ON signals are steady, while output VCCK changes between 0.7-1.1V according to the screen flashing...

Seems that it is a processor fault. Do you have any other idea?

[dick_barton]

Re: Philips 221TE4L flashing screen

What voltage do you have at the junction of R934/937 or Pin 10 of IC801 - OZ9998AGN.
It should be between 0.2v to 1.2v maximum

[Maxmad]

Re: Philips 221TE4L flashing screen

this voltage on pin 10 is between 0.6v and 1.7v when the panel lights.

[dick_barton]

Re: Philips 221TE4L flashing screen

Sorry but I had my OVP & OVP1 mixed up.

The point to measure is IC904 pin 14 (RT8482GS) which should not have a voltage greater than 1.2V

Over Voltage Protection. The PWM converter turns off when the voltage of the pin goes to higher than 1.2V.

[Maxmad]

Re: Philips 221TE4L flashing screen

there is a mess with the schematics...
The TV model is 221TE4L however the correct PCB layout is on page 48 for 231TE4L...

So there is no IC904, but instead there is the IC801... not easy to find some datasheet for it...

[Maxmad]

Re: Philips 221TE4L flashing screen

Also... the tv doesn't start neither with the on/off button nor with IR remote...
It starts only when you plug it with the ac cable.

on/off button uses signal ADIN2_SRV (page 52) which goes directly to MT5366 (pin 145 - page 51).

Does MT5366 uses this signal to produce OPWRSB for power on? (page 49)
OPWRSB must be low.
There is no change when tv is in standby mode and the on/off button is pressed...

[dick_barton]

Re: Philips 221TE4L flashing screen

The symptons you describe appear to mimic a bad EEPROM (SPI) boot up problem as seen on many Vestel sets.
Try freezing the EEprom (aerosol freezer) and see if it will start up.


Page32, U406, MX25L4005AM2C-12G (4Mbit SPI)

[Maxmad]

Re: Philips 221TE4L flashing screen

The correct schematic for the logic board is from Chassis TPM8.2E (Second attached 10.43MB).

May the U409 have the same problems? (page 52)

[angel-boy]

Re: Philips 221TE4L flashing screen

i have a problem with this tv ,

hdmi not working.

i did not find firmware to upgrade. any help ?

[geoelec]

Re: Philips 221TE4L flashing screen

Four led strips inside the panel are connected in two in the connector and drived as a dual channel by OZ9998AGN having in parallel connected four led input per channel.Trying to connect in parallel oz9998 all inputs as a single input and then you will see if the chip is defective or the led strip.Probably the two inputs are not conducting the same and this shuts off the light.There is no eeprom problem in such case.

[diretouch]

Re: Philips 221TE4L flashing screen

hi there.

in short - i don`t have a lot successfull electronics repairs although i have a lot of equipment and not small knowledge of this area. I have here one such TV.
It has normal picture and sound but the LED is blinking and the TV does "what it wants" like changing programs and cannot function normal.

I want from you some concrete advices what voltage to measure what form of the signal to show you from osciloscope and such.

Of course i am appling photos and will give additional info about what you ask me.

The device is almost new and is not used a lot

Thanks in advance!