IQ SMART TV 22" weird problem

[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

[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

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

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

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.

[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

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?

[rippergr]

Re: IQ SMART TV 22" weird problem

The TV is led not lcd so it has no backlight

[attainteddragon]

Re: IQ SMART TV 22" weird problem

bud, should this ps power the backlights as soon as the main is disconnected?
pull up resistors on the ps.

just wanted to make sure there was not multiple issues first.

[budm]

Re: IQ SMART TV 22" weird problem

It probably does not have pull-up resistor for self test. Since the standby power supply is 12V instead of 5V, you will use 2K resistor between 12v and ON/OFF, it also may require another 2K resistor between ADJ and 12V.
"The TV is led not lcd so it has no backlight" it uses LEDs to create the backlit or edge lit (more likely) for the light source.

[rippergr]

Re: IQ SMART TV 22" weird problem

It probably does not have pull-up resistor for self test. Since the standby power supply is 12V instead of 5V, you will use 2K resistor between 12v and ON/OFF, it also may require another 2K resistor between ADJ and 12V.
"The TV is led not lcd so it has no backlight" it uses LEDs to create the backlit or edge lit (more likely) for the light source.

I've never done something like this before.
Can you tell me exactly where should I put the resistors?
I just put a resistor 2k in the 12V and on off pin and give power to TV?

[attainteddragon]

Re: IQ SMART TV 22" weird problem

disconnect the cable that goes to the main board from the ps.
use a 2k resistor to jump from 12v to on/off.
either place it into the connector holes that are now available at the end of the cable that you just disconnected, or wedge it into the cable connector that is still attached to the ps.

if this does not turn on the backlights when power is applied (no buttons need to be pressed), then add another resistor between 12v and adj, then apply power again and you should see backlights but no picture.

this will let you know that the ps, backlights and panel are ok (visually).

after this, you can return to the main board that has your issue, whether it can be fixed or replaced, but at least you will know that you should have no other issues at this point.

[rippergr]

Re: IQ SMART TV 22" weird problem

disconnect the cable that goes to the main board from the ps.
use a 2k resistor to jump from 12v to on/off.
either place it into the connector holes that are now available at the end of the cable that you just disconnected, or wedge it into the cable connector that is still attached to the ps.

if this does not turn on the backlights when power is applied (no buttons need to be pressed), then add another resistor between 12v and adj, then apply power again and you should see backlights but no picture.

this will let you know that the ps, backlights and panel are ok (visually).

after this, you can return to the main board that has your issue, whether it can be fixed or replaced, but at least you will know that you should have no other issues at this point.

Ok. I put a 2.2K resistor on 12V and ON/OFF pin and I have backlight on the screen. I still hear the weird sound .
Do you have any idea what should I look in the main board?

[attainteddragon]

Re: IQ SMART TV 22" weird problem

so ps and screen are good. the sound may always be there and your only noticing it since you have the back off and your next to the ps. it is hard to tell for sure from a keyboard.

on the main, i would check all of the caps, then if that gets you no where, i would try to do a reflow of the main processor that is under the heat sink. if it is a bga chip, they do tend to fail with broken solder connections. outside of that, you could be looking at the eeprom chip.

main boards are a bit annoying and you could be up for a replacement board at the end of the day.

[rippergr]

Re: IQ SMART TV 22" weird problem

The sound is always there when the TV cannot turn on. If I turn it on the sound disappears. The caps are all good, at least with eye inspection.
I did a reflow on the chip (it is bga) but still the same. I only have the red standby led but cannot power on the TV.

[attainteddragon]

Re: IQ SMART TV 22" weird problem

caps can fail without any visual signs.

you can try and freeze the eeprom chip, it may boot when frozen.

[rippergr]

Re: IQ SMART TV 22" weird problem

I don't have freeze spray but I have compressed air wich freeze it but it doesnt turn on. Can I try and inject voltage to a regulator to see if it turns on?

[attainteddragon]

Re: IQ SMART TV 22" weird problem

unfortunately it looks like you need another main board.
unless someone else can suggest something else that you can try.

[rippergr]

Re: IQ SMART TV 22" weird problem

I was trying to turn it on those days and I couldn't . I left it with power for 3-4 hours and then it turned on.
I have 5 V on pins on/off and adj
and in all regulators 3.3V in middle pin and 5V in right pin.
Also the weird noise dissapeared as soon as the TV turned on.
It is as something is not charging correct and it has to get a lot of voltage before it can turn on.

[dskall]

Re: IQ SMART TV 22" weird problem

You can try heating/cooling different areas of mainboard to see if it makes a difference.