HP LA2306X monitor does not turn on, does not respond to power

Hello, I have a monitor as in the title to do that does not turn on.
After checking, it turned out that one Schottky diode (shorted) with the designation SR520N FIN is damaged and that they were next to each other, I have already replaced both. Maybe someone will tell you where to look further or what measurements I would have to check.

MOSFET transistor controlling the converter, working? Control board, checked components?

In one of the places there was a Schottki diode screwed to the heat sink, no short circuits and the conductivity in one direction is not the other way, so I conclude that it is working, as for the 2764AA mosfet, and I do not know how to check it exactly, between G> D there is no conductivity on the meter and on D (-) S (+), the meter is set to "squeak" 528 ... There are moments that between D / S squeaks like a short circuit. If I am doing something wrong, please be understanding

We take measurements on the desoldered elements.

Of course I did

OK. There is a diode between D and S. AP2764..pdf (58.49 kB)You must be logged in to download this attachment. Check the optocoupler is it still working?

One way DS is 528 set to beep.
The optocoupler is not short-circuited.

Added after 15 [minutes]:

After turning on the power, the two LEDs show 2.6 V is it not enough

in the marked points, if I give to red plus and to 5b or 6 pin minus. The power supply is fluctuating between 0.95 and 1.01V.

It is operational. Are you looking for further check this module what is a small soldered laminate to the board, is there something damaged there? Have you checked the capacitors?

I forgot to add that on the Schottky diodes, as I wrote at the beginning, one was shorted.

Post to me all the photos of this power supply from the elements side and from the print side with good resolution?

maticz23 wrote:

in the marked points, if I give to red plus and to 5b or 6 pin minus. The power supply is fluctuating between 0.95 and 1.01V.

At the marked points, the cable goes to the control board. I do not have a diagram, but in my opinion the voltage is low there and it should be constant and not fluctuate

There should definitely be at least 5V for the motherboard's power supply.

PITERRR wrote:

Post to me all the photos of this power supply from the elements side and from the print side with good resolution?
Please, this is what I managed to do

Check on this board Q1, D1 U830 what is this inverter driver? There are no cold solders on the connections and the optocoupler is operational? I851 is TL? and there was also a transistor, check it out?

Hello,
I'm a freshman here and I have a question - from which year is this damaged monitor? I am asking because I have exactly the same model and it also stopped working ...; (I wonder about the cost of repair and the possible purchase of a new one

This monitor is from around 2010/2011
Made on the basis of what Philips
* I won't tell you which model> but look and look for something on the forum
* there were used strange chips from OZMICRO, made for Innolux
* by the way, about which nothing is known, no datasheet

There you have a LED backlight module on U1 INL859RN (INL859) 16-pin
- After the pins, it resembles OZ9998B, something was written on the forum (monitors or TV service) Link
* operating principle OZ 9998LN (QFN24)

The correct power supply is on the module (pin) with the U830 (INN801B) 8-pin (pin 7 cut), which controls the field on the heat sink.

It produces + 5V and probably + 15V
The layout must be drawn on a piece of paper and then see maybe there is an equivalent (analog), e.g. using Link
There, the power supply from + 300V, after the diodes should go through resistors on the pin, probably (8), ..

You have opto feedback. and TL431, excl. gives on the pin.FB of the chip
Replace them (or check them out)

ps
In the enclosure there is a hand-drawn diagram inv. under the LED (there may be errors)


The one in the power supply may be something "ala

or (from Philips stby system) / sorry, the quality is not as it should be

Wow! thanks for such a detailed exploration of the topic
Mine produced in 2012 and this week I hope to do a self repair approach ...

monitor disassembled, tiles and all layouts perfectly clean ....
initial correct measurements ...
now it remains to look for a needle in a haystack (only the question of whether it makes sense to waste time or better to invest in a new monitor)
similar to you?

I mean, what initial measurements did the colleague take?

To be clear - I am not an electronics expert, I am only briefly interested in the subject. Measurements of diodes, coils - as I wrote, only briefly and quickly checked, without desoldering. today I am posting material to a colleague who is familiar with the subject and we will see what he will discover. It will probably take a while because it is not good for him with "split time"

And it is possible to give the monitor to a specialist in this field.

Welcome back. The message is that the monitor has been repaired (replacement of the converter, resistor, capacitor and diodes, PLN 88 in total). the repair cost is high, but it may pay off somehow if the monitor lasts another 3500 hours .... hopefully