Problem Source HKL-240101

[gua45]

Hi all:
Again here to ask for new help.
The previous time I'm still waiting for power
get a T-con Runtk 5249TP, when you receive it
I will communicate results.
This time it's a problem on an I-Joy TV, with a
problem in the power supply HKL-240101 that in principle
did not light anything, I changed the resistance R-910 the R-907 the Mosfet Q901 (JCS7N65FB) and U901 (OB2273).
After these changes the power LED goes to blue level but
the voltage of the backlight LEDs is 12 volts only, so they do not light up. I try them with an outside source and they
they illuminate correctly.
I test the integrated circuit U1 (OB3350cp) and the voltages I measure are:
Pin 1 = 3.48v
Pin 2 = 0 v
Pin 3,4,5 and 6 = 0 v
Pin 7 = 0.32 v
Pin 8 = 4.37 v
Which tells me that this integrated is wrong, but the problem is that I can not find it, I would like to indicate one that was similar to this one.
Thanks in advance and greetings.

[CapLeaker]

Re: Problem Source HKL-240101

what do you get on the LED connector without the LED's connected to it? The voltage should ramp up.

[gua45]

Re: Problem Source HKL-240101

Hello CapLeaker:
Acontinuacion step to inform you of the tensions
that are measured, in the CN1 connector that goes to the backlight LEDs.
TV connected and blue led on with cable disconnected.- 11.21v
Connected TV and blue LED on with connected cable.- 11.21v.
In the CN902 connector that goes to the Main Board the voltages with
Connected cable are:
Pin 1.- +11.51 v
Pin 2-3.- +5.06 v
Pin 4-6.- GND
Pin 5.- +4.85 v
Pin 7.- 0.027 v
Greetings and thanks for your guidance

[CapLeaker]

Re: Problem Source HKL-240101

can you upload a high resolution picture of the top of the whole PSU? Like this the pin numbers do not tell me anything.

[budm]

Re: Problem Source HKL-240101

https://www.badcaps.net/forum/attach...3&d=1550514215
Pin 5.- +4.85V is DIM control: OK
Pin 7.- 0.027V O/F = BL-ON: BAD (if it is Active high signal type)

[gua45]

Re: Problem Source HKL-240101

can you upload a high resolution picture of the top of the whole PSU? Like this the pin numbers do not tell me anything.

CapLeaker, I send you a picture with the information
that you request, I hope it serves you.
The backlight LED strip is on the bottom of the
TV and is composed of 60 led, of which the source feeds
30 plus 30 in parallel.
A greeting.

[gua45]

Re: Problem Source HKL-240101

https://www.badcaps.net/forum/attach...3&d=1550514215
Pin 5.- +4.85V is DIM control: OK
Pin 7.- 0.027V O/F = BL-ON: BAD (if it is Active high signal type)

Hello Budm,
could you tell me what voltage should have pin 7 (BL-ON) and if that
Does the voltage come from the Main Board or from the power source?
And in the connector CN1 what voltage should there be to power the led
backlighting ?.
I do not have the plane of the source.
Greetings and thank you.

[CapLeaker]

Re: Problem Source HKL-240101

BLon or PSon doesn't have to have an exact voltage, but something from 2V to 5V should suffice. PSon and BLon are generated on the main board and tell the PSU to turn all the voltage rails on and the back lights on.

To force the PSU on by itself without the main board, you can take a 1k resistor and jump STBY to to PSon and STBY to BLon (through a 1k resistor each). That will turn on the PSU all voltage rails and the backlights as soon as you plug it in.

[gua45]

Re: Problem Source HKL-240101

CapLeaker, what do you mean that a pin 2-3, which has + 5v with pins 5 and 7 through a resistance of 1K each and having disconnected the cable that goes to the main board, should turn on
the led strip ?.
A greeting.

[CapLeaker]

Re: Problem Source HKL-240101

Unhook the main board from the PSU. On the power supply, take a 1k resistor and jumper STBY to the On Off pin. Plug the PSU in and all the voltage rails, plus the back lights should be on. If it doesn't work, take another 1k resistor and jump STBY to the DIM pin.

CN902 has a pin out legend that says what pin does what.
12V
5V
5V
GND
DIM
GND
OnOff

[gua45]

Re: Problem Source HKL-240101

Thanks CapLeaker, today I go on a trip and I do not
I'll be back until March 5, when I do
I try what you tell me and I already told you.
Greetings and thanks for your interest.

[gua45]

Re: Problem Source HKL-240101

Hello Capleaker.
Back from my trip, I've done the test you tell me in the
post 8 (disconnecting the PSU from the source and putting the + 5v with two resistors in series of 1K with the pins DIM and On / Off). The result of the test is the one indicated in the attached file.
As you can see, the backlight LEDs turn off and on continuously and do not remain fixed.
Waiting for your opinion I greet you and thank you.

[CapLeaker]

Re: Problem Source HKL-240101

the resistors are not in series! It is one resistor from STBY to On/off and the other resistor from STBY to DIM!

The last time I had LED's flash like that, the output caps for the LEDs on the PSU were bad. Did you check the caps yet? Only because they "look good" it doesn't actually mean they are good!

[gua45]

Re: Problem Source HKL-240101

Las resistencias estan bien colocadas, si te fijas en el video, una va a DIM y la otra
a On/off.
La Main Board no esta conectada a la fuente de poder.
No entiendo que quieres decir con "Did you check the caps yet?"

[CapLeaker]

Re: Problem Source HKL-240101

No entiendo que quieres decir con "Did you check the caps yet?"

What I meant is: Did you check the output capacitors for the LED's on the power supply?

[gua45]

Re: Problem Source HKL-240101

That's the first thing I did, all the electrolytic capacitors that the power source has
change them completely.
The behavior of the source seems like it wants to boot but it does not.
Would it be useful to change the optocoupler that it carries?
I've tried it and it's apparently fine and that's why I have not replaced it.
A greeting.

[CapLeaker]

Re: Problem Source HKL-240101

I test the integrated circuit U1 (OB3350cp) and the voltages I measure are:
Pin 1 = 3.48v
Pin 2 = 0 v
Pin 3,4,5 and 6 = 0 v
Pin 7 = 0.32 v
Pin 8 = 4.37 v

I looked at the spec sheet of U1.
Pin 1 = Vin and supposed to be something between 8 and 35V. You have 3.48V and that is not going to work.

[gua45]

Re: Problem Source HKL-240101

Well I've already gotten the screen to turn on,
I changed the smd capacitor, C-6 that goes with a resistor
in series from 10k to leg 6 of the integrated circuit, U1.
Voltages in integrated circuit, U1
Pin 1.- 9.44v
Pin 2.- 7.13v
Pin 3.- -0.29v
Pin 4.- -0.21v
Pin 5.- 0v
Pin 6.- 1.09v
Pin 7.- 1.06v
Pin 8.- 4.31v
I only have to diagnose, because there is no tension On / off of the
main board to the PSU.
In attached files I accompany photos of the palace, in case it has
a diagram of it that provides it to me, to see where
part tension On / off.
Greetings and thank you.

[CapLeaker]

Re: Problem Source HKL-240101

If I understand correctly, you have now the back lights, but there is no On/Off coming from the main board.

Here is a little flow chart on how it goes: STBY voltage is sent from the PSU to the main board. On/Off signal would be generated on the main IC on the main board, once you press the power button on the TV. That On/Off signal would go from the main board to the PSU, telling the PSU to turn all voltage rails and back lights on. TV turns on.

However, I do see a couple of LDO's on the main board that could prevent the main IC from running correctly. Also the power button itself, frimware and eeprom could do that. If the main IC on that main board is made by MSD followed by some numbers, there is a very high chance that this IC is bad.

[gua45]

Re: Problem Source HKL-240101

Hello CapLeaker.
As you comment on the power on / off of the main board and the tests that I have carried out, I come to the conclusion that the Main Board would have to be changed.
In view of which I do not deserve to spend what is worth that plate and therefore
I leave this fault parked, until I find another waste TV that has the plate in good condition.
Greetings and thanks for your interest.