Re: LED Driver board Question
Do you have LED tester so you can test and check the Vf of LED strings?
So it's the Digital Signage display.
LED Driver board Question
Collapse
X
-
-
Re: LED Driver board Question
its nice set, good candidate for Android / linux TV project instate as store display...LOLLeave a comment:
-
Re: LED Driver board Question
Just one more image to give you an idea of what I'm looking at right now. I took apart the 50 inch panel completely to get at the backlights, so I'm very relieved that the screen seems to be okay.
This is the level of light I get with the 2R2 resistor in place.Leave a comment:
-
-
Re: LED Driver board Question
You will notice that if you search for v500hj1-pe8 LEDs, you will find something like the link below.
https://spares2repair.co.uk/sound-vi...ts/v500hj1-pe8
And these are not the LEDs in my version. My version has edge LEDs similar to this:
Leave a comment:
-
Re: LED Driver board Question
Edge= LEDs with out lens at the bottom the Type could be single or Double LED unit.
Direct= LEDs with Lenses direct behind the screen. as in the net show of this Display LEDs Type 3035 6V.Leave a comment:
-
Re: LED Driver board Question
innolux v500hj1-pe8 is the panel. Just be aware that the LEDs that they sell for this one are NOT the same as what is in this panel. The LEDs in my version of the screen are all at the bottom of the screen, there are two LED strips and each has four parallel sets of 26 LEDs. The back of the panel says 720ma / 78-89V
It is a store display unit where people can walk up to it and look for websites and they can run demonstration videos on. If I was to describe it, it looks like a 6 foot mobile phone. My seven year old nephew asked me what it was, and I told him that a giant had asked me to fix his iphone.Leave a comment:
-
Re: LED Driver board Question
D2330 on the first line?
Second line I cannot read.
You can turn up the backlights level then measure the Voltage drops on that resistor to calculate the LED current.
The LED strings look to be connected in parallel.
What is the panel number any way?Last edited by budm; 08-12-2020, 01:32 AM.Leave a comment:
-
-
Re: LED Driver board Question
use one Res as you calculated will work smoothlyLeave a comment:
-
Re: LED Driver board Question
BTW, what is the IC U1 P/N?Last edited by budm; 08-11-2020, 05:31 PM.Leave a comment:
-
Re: LED Driver board Question
you have 5 rank only 2 used.. it mean the same power boards used by other TV size.. here are the Numbers of LED play the roll. use one Res as you calculated will work smoothly.
but the question always remain why they are OPEN... need to inspect the LEDs firstLeave a comment:
-
Re: LED Driver board Question
I see it. It must be pretty forgiving, as I have increased the resistance at that junction from 0.29 ohm to 2.2 ohm and still the backlight comes on and stays on. I think I'll just replace those resistors with exactly what was there previously.
thanks.Leave a comment:
-
Re: LED Driver board Question
They are current sensing resistors for maintaining constant current through the LED's.
You can see the VIAS on the CC cooper plane that goes back to the control circuit.
They set the maximum current by adjusting the values of the sensing resistors.
So for the resistor may be burnt out due to some shorted out LED's.Leave a comment:
-
Re: LED Driver board Question
My apologies, I had the output cable turned upside down. I just noticed A and C on the output connector, which I presume is Anode and Cathode of the LEDs - so those resistors connect the cathode side of the LEDs to ground.
There is nothing on the back side of the board. So I think the purpose IS current limiting, not current sensing. I dont want to take up any more of your time, guys, so I think I'll just get the same resistors as what was in it. I will improvise on the next one!
Last edited by JonathanAnon; 08-11-2020, 02:12 PM.Leave a comment:
-
Re: LED Driver board Question
Can I see straight shots pictures of the whole top and bottom side of the board?
They may be being as current sensor.Leave a comment:
-
Re: LED Driver board Question
On the TVs I repair, I reduce the current through the LEDs to a correct illumination of the panel. In this way I protect the LEDs when the user increases, from the menu, the voltage to the maximum. This prolongs the life of the backlight.Leave a comment:
-
Re: LED Driver board Question
Interesting Dick, I didn't know that they need to be that finely "tuned".
So here's my plan. The resistance that would have been there originally would have been 0.28 ohms (2ohm and 0.33 in parallel). Now, I have a load of 2R2 SMD resistors, so I'm gonna put five of them in the parallel on the available pads which gives effective resistance of 0.44 ohms. This will reduce the current, which is what I want, and will also mean I don't have to order any small bits in the post. I will checked afterwards to make sure that there is enough current in the LEDs so that the screen has adequate backlight.
Anybody have any issue with this?Leave a comment:
-
Re: LED Driver board Question
It's not unusual to have a mix of resistors in parallel to give you the exact value you want.Leave a comment:
Related Topics
Collapse
-
Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?by Tynan DillI was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.
Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
Assuming...7 Photos -
by m1ch43lzmHi, this is my personal laptop, which the original board (lets call it Board A) blew up PU8700 (TPS51486), making a hole on the board, i had left the laptop at my desk one day with the battery fully charged and didn't touch it for a week, but when i tried to turn it on it didn't
Thought the battery was dead, so i plugged in the charger then tried to power on, the power LED blinked once, charged LED still orange, unplugged the charger, plugged in again and I noticed the "magic smoke" smell, so i unplugged the charger, removed the back cover and saw the blown IC (the "magic... -
by ugamazingWorking on a 2023 M3 A2992 unit with 820-02918 board, and it uses a new USB-C power architecture, with rectangular controllers. I do not have a perfect-matching board, so have been repairing this one the old-fashioned way (slowly).
I managed to blow-away a single resistor that I can't find and can't determine the value of. It connects to ground, so I went ahead and stuffed it with a 100K resistor in case it's a simple pull-up. But, I'm now having issues with that side of the board, and am curious if it's possibly related to this resistor! I have no schematics and no board view, so... -
by Ancient1Elco (?) 50" Smart TV. Backlight ( BL) issue.
Single Board : TP.SK708D.PC821
I bought new BL set . - OK
Power up : Blip . Protection.
Led Tester shows current at 34.2 mA , Previously it was 42.1 mA
Solution : Change current output .
The BL IC is marked on the photo and datasheet is QOB33535 Datasheet(PDF) - Schneider Electric (alldatasheet.com)
Calculating according to the datasheet - see attached photo :
With ILed = 34.2mA , equation #1 is RFb = 400mV / 34.2 = 11.7 Ohm , and with 42.1 mA we get 9.50 Ohm . i.e I should look for 9.5 Ohm...4 Photos06-09-2024, 12:25 PM -
by howardc64Problem
This is an LG edge LED lit LCD Display. The LEDs are on the bottom edge of the display. There are 2 bars (left and right) Each bar has many LEDs and a 6 pin connector. Each pin drive several LEDs thus is the highest current flow / heat junction. The weak lead free solder gradually fails with thermal expansion/contraction cycling and increases resistance. PSU will compensate up to a point, then when the current is too high, PSU just shut down the backlight causing a dark display. I have even seen one which the connector just fell off as solder points became completely detached....-
Channel: Troubleshooting Computer Displays
-
- Loading...
- No more items.
Leave a comment: