Need help identifying smd

[caphair]

Re: Need help identifying smd

Thank you.

As far as this unit, am I at a loss without a schematic? Let me add that if the unit has been unplugged it'll almost always turn on as it should the first time

[caphair]

Re: Need help identifying smd

I traced that 5v line to this circuit on the back of the LCD display. 5v feeds into Q5. Unfortunately due to how this thing is made its impossible for me to take measurements with the cover off and it connected to the DVD side of the radio. It needs the back cover to snap and keep it in place.

However I wonder if Q5 is sometimes not turning on when 5v is fed to it? Is there anyway I can test it without power? Considering it seems to be an intermittent issue. The label on Q5 is A1H

[budm]

Re: Need help identifying smd

What is that white connector for?
Can you zoom out to see the whole board?
Also like to see how all the wires from the LCD panel are connected to the boards.

[caphair]

Re: Need help identifying smd

That white connector is like a CFL connector but this couldn't use cfls right?

Here's the entire board that's behind the LCD display

[caphair]

Re: Need help identifying smd

Closer look at LCD connector underneath kapton tape

[budm]

Re: Need help identifying smd

That section is the Voltage boost converter for driving the LED backlights, it is not using High Voltage for CCFL otherwise that Black/White wires will be dressed like that close to other circuits.
So the question is, you are not seeing anything on the screen due to lack of backlights or the backlights are on but no video on the LCD panel?

[caphair]

Re: Need help identifying smd

It seems like no backlights because led buttons come on, there's audio.

Also when I get a display I tried putting backlights up fully then when I get no display the screen is dark. I figure if backlights were working I'd see bright white light and no video

[caphair]

Re: Need help identifying smd

The tft on/off line which is the 5v I was tracing runs to that booster circuit for the LEDs.

[budm]

Re: Need help identifying smd

The tft on/off line which is the 5v I was tracing runs to that booster circuit for the LEDs.

So that is probably the same as BL_ON (Backlights ON) signal to run on the Backlights just like in TV.
So you should be able to see DCV between that Black and White wires, I would leave the meter probes on those two wires BEFORE turning on the unit and write down the DCV reading, then turn on the unit and see how high the Voltage will jump up to and see if it comes back down later on. You should leave the meter to be able to read the Voltage up to 50VDC.

[budm]

Re: Need help identifying smd

BTW, can you read the P/N of that IC U13?

[caphair]

Re: Need help identifying smd

The issue with that is I can't take measurements with the display connected it won't stay in place unless the back cover is on

[caphair]

Re: Need help identifying smd

Yes the part number is le2j

[caphair]

Re: Need help identifying smd

Ok so I noticed the disc drive doesn't power up when I have no display. I wonder if it's triggered when backlights or LCD are on?

[budm]

Re: Need help identifying smd

What is the Value of that cap DC7?
Is one leg of DC7 connected to the pin of the LED connector that has + label next to it?
An the other leg of the LED connector shows low resistance to GND?

[budm]

Re: Need help identifying smd

Ok so I noticed the disc drive doesn't power up when I have no display. I wonder if it's triggered when backlights or LCD are on?

May the processor may have cutoff the control signal to the backlghts if there is problem with the drive or other circuits, I really do not know.

[caphair]

Re: Need help identifying smd

What is the Value of that cap DC7?
Is one leg of DC7 connected to the pin of the LED connector that has + label next to it?
An the other leg of the LED connector shows low resistance to GND?

It's 1uf 50v
Yes positive pin of DC7 connected to + leg of LED connector. The other leg of LED reads about 3.2 ohms to ground.

[budm]

Re: Need help identifying smd

It's 1uf 50v
Yes positive pin of DC7 connected to + leg of LED connector. The other leg of LED reads about 3.2 ohms to ground.

So then you can monitor the DCV between the two legs of that cap.

[caphair]

Re: Need help identifying smd

Less than 1v when no display and about 10v when display on

[budm]

Re: Need help identifying smd

So when the it is not working, the Voltage will go to 10V when first power on the unit and then it goes down to nothing?
Even if the backlights are not on so you cannot see anything on the screen the other functions of the units should keep on working, if that is not the case you have problem some where else.

[caphair]

Re: Need help identifying smd

No if it's working the voltage goes up then settles at 10v and when it's not working it stays at less than 1v