IQ SMART TV 22" weird problem

[rippergr]

Re: IQ SMART TV 22" weird problem

The TV is led not lcd so it has no backlight

[rippergr]

Re: IQ SMART TV 22" weird problem

This TV has an always on power supply, the ON/OFF pin that you measured 0V is the Backlight ON/OFF control pin and right now the main board is not sending the ON command to turn on the backlights.

OK. So I must put a resistor 470 to 1K on the ON/OFF pin?

[budm]

Re: IQ SMART TV 22" weird problem

This TV has an always on power supply, the ON/OFF pin that you measured 0V is the Backlight ON/OFF control pin and right now the main board is not sending the ON command to turn on the backlights.

[rippergr]

Re: IQ SMART TV 22" weird problem

have you jumped the ps on with a resistor to (470 to 1k) see if the backlights and ps are all working properly? disconnect main for this.

I didn't understand what should I do with a resistor. Can you give me a little more details.

[attainteddragon]

Re: IQ SMART TV 22" weird problem

capacitance will only give you half the answers as to if the caps are good or not.
you can download an esr chart easy enough.

have you jumped the ps on with a resistor to (470 to 1k) see if the backlights and ps are all working properly? disconnect main for this.

[rippergr]

Re: IQ SMART TV 22" weird problem

I don't have esr meter. Can I check it whith some other way? I have a meter that you put different componenet and tells you what it is (resistor,capacitor, diode etc) which measures the capacitors but I don't now if the values are good (I only understand uF , it gives me some readings like esr but I dont know the "good"values)
I had changed 3-4 capacitors but I didn't see any change in the behaviour.
When the TV came it has the thermal fuse blewed and I changed that.

[attainteddragon]

Re: IQ SMART TV 22" weird problem

the 3.3v regulator is good. looks like the others get their voltage when the ps comes up.

if you have an esr meter, i would check all of the caps on the main board.
if they are ok, you might be looking at an eprom failure.

[rippergr]

Re: IQ SMART TV 22" weird problem

all of them are 1117 B 33 632K
and all of them have 0v on all pins except the top one which has 3.3V on midle pin and 5V on right pin and 0V on left pin

edit: The top regulator has the voltages not the top one pin

[rippergr]

Re: IQ SMART TV 22" weird problem

all of them are 1117 B 33 632K
and all of them have 0v on all pins except the top one which has 3.3V on midle pin and 5V on right pin and 0V on left pin

[attainteddragon]

Re: IQ SMART TV 22" weird problem

these are your voltage regulators.
i cant make out what the output voltage should be from the pics.

measure them from left to right. center pin is the same as the tab pin.
list what is written on the top line of each ic.

[rippergr]

Re: IQ SMART TV 22" weird problem

What do you mean regulators? you mean transistors?

[dskall]

Re: IQ SMART TV 22" weird problem

Your not getting any change on on/off pin? Need to check voltages on main at regulators

[rippergr]

Re: IQ SMART TV 22" weird problem

If I unplug the logic board I cannot power on the TV, it has no lights.
The voltages on the pins are on 12V rails 12.05V and in all other 0V

[dick_barton]

Re: IQ SMART TV 22" weird problem

With the main board disconnected what voltages do you have on pins 1-6 when you switch on?

[rippergr]

Re: IQ SMART TV 22" weird problem

Anyone has any idea what to look/change?

[rippergr]

Re: IQ SMART TV 22" weird problem

Ok the pins are

Descr. Standby Volt Power On Voltage
1)+12V 12.05 12.05
2)+12V 12.05 12.05
3)on/off 0.03 0.03
4)ADJ 5.03 5.03
5)GND
6)GND

I hope the pictures are clear

[dskall]

Re: IQ SMART TV 22" weird problem

Need good clear straight on pictures of back of tv with cover off and each board.

Need voltages from connector that goes from power supply board to main board. Will need pin#- PIN DESCRIPTION -Pin voltage in standby-Pin voltage when pushing power button and picture of connector on power supply board.
Format:
Pin# - Pin Description - Pin Voltage standby - Pin voltage power on
1 - XXXXXXX - XXv - XXXv
2 - XXXXXXX - XXXv - XXXv
3 - XXXXXXX - XXXv - XXXv
4 - etc.

[rippergr]

Re: IQ SMART TV 22" weird problem

I would carefully inspect board for bad connections. Heat or cool board to see if it will turn on.

I resolder most of the components . I cool the board and I heat it but it still does the same.
Is there any change that it's problem from the thermal fuse (I changed it because it was burned) or the yellow square capacitor?

[dskall]

Re: IQ SMART TV 22" weird problem

I would carefully inspect board for bad connections. Heat or cool board to see if it will turn on.

[rippergr]

Re: IQ SMART TV 22" weird problem

Might pull con1 and see if any arcing in connector or bad solder joints

That was a good idea. I removed the con1 and solder a cable directly on board but still the same noise and cannot power on the TV altough it has the standby led when I push the on button nothing happens or just shut down the led.