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Panasonic TH-L50B6D LED 1 Blink Code
BookWormStud:
--- Quote from: downunder on August 16, 2017,20:27:39 ---
The BL-ON function of pin on P2 (14 pin) I have surmised from the behaviour of the voltages you provided. You say it fluctuates between 1V and 4.5V. I could be wrong, but 4.5V this sounds like the level BL-ON would reach. The functions you have allocated to P2 on your attachment (last post) - are they the real deal as per service manual for your model? This keeps confusing me, the different number of pins in various attachments.
Re the resistor, my intention was for you to do it with all connectors in place. You can either force it into the top of P2 or solder it to the relevant pins on the underside of P2. THen, A-Board supplies Power-On, you supply BL-ON.
Bruce
--- End quote ---
OK I tried some new things,
Firstly I discovered that Pin 12 on P2 Connector is indeed BL_ON.
Now what I did, With every connector attached I one by one disconnected the wires labeled
BL on Connector connected to A09. Pin 12 when disconnected Backlights don't light up.
Then Connected Pin 12(removed from connector A09)
to Pin6 of 5Vs (connected at Connector A09)
Like this
Backlights light up but same flickering. Also disconnected every other wire with BL prefix
Thought maybe they were sending a bad signal but no luck.
I wanted to ask another question. If one or more of the LED in backlights is bad then when directly
Connected to 5Vs shouldn't it give maybe dim light but constant why do they flicker if LEd is short or bad?
downunder:
Wrt your procedure, I would expect the backlights to be constant. At least that eliminates the A-board, but you have a problem elsewhere. Could be the LD-board but they're generally reliable. Most likely a faulty LED. Also, when you remove other BL related cables, you're removing other info related to BL operation e.g. PWM (pulse width modulation) controls the brightness and current of the LEDs, BL-Error tells the micro of any defects in the LEDs which generates Code 1.
Ever pulled a panel apart to expose the back light LEDs? Might be a big ask for a dabbler as you could end up with a cracked display panel.
Bruce
BookWormStud:
--- Quote from: downunder on August 17, 2017,05:11:46 ---
Wrt your procedure, I would expect the backlights to be constant. At least that eliminates the A-board, but you have a problem elsewhere. Could be the LD-board but they're generally reliable. Most likely a faulty LED. Also, when you remove other BL related cables, you're removing other info related to BL operation e.g. PWM (pulse width modulation) controls the brightness and current of the LEDs, BL-Error tells the micro of any defects in the LEDs which generates Code 1.
Ever pulled a panel apart to expose the back light LEDs? Might be a big ask for a dabbler as you could end up with a cracked display panel.
Bruce
--- End quote ---
Haven't even opened a back cover of an LED TV before. I'm thinking of replacing Backlight as Last Resort. I just wanted to turn on the Backlights with A-Board disconnected which is the main issue, if I somehow be able to rule A-Board out to be good then I'll move on.
But it seems like impossible.
I think Now what I'm gonna do I'm gonna use a resistor to jump Pin 6 = 5V to all other pins which gives a Backward & Forward signal all together.
Is there any other way to put DC voltage (using a battery) to LD3 and turn a strip ON. Is it even possible?
Another question how can I check Backlight array model?
BookWormStud:
One more thing I read a post on justanswer.com TL;DR Some resistor were open circuit that's why Backlights flicker.
I check the resistors on my P-Board there are total of 3 resistors which read open circuit. Every other resistor makes a beep sound on my Multimeter under continuity test (which states that circuit is complete). Is this natural or something is wrong?
Open Resistors on P-Board
Top View
Bottom View
EDIT :
Turns out those resistors values were more than the range of my Multimeter's Continuity test.That's why they didn't beep. So ignore this.
downunder:
You've already ruled out the A-board by severing the BL-ON lead and activating the LEDs using the resistor bridge.
Resistors shown appear to be 1 megohm so they wont beep.
I cannot recommend linking pin 6 willy-nilly to other pins on the plug. You don't know what damage you'll do, especially to the 1.8V rail.
Power-On and BL-ON are the only two we ever bridge out to the 5V pin.
Re applying voltage to the LED strips, that is where we use the LED-Strip Tester. It automatically and gently ramps up the volts it applies to a strip until
the strip illuminates and then it stops there. If you open the panel, you can test individual LEDs with your digital meter on diode mode. Some meters
will apply enough volts to light up a single LED provided it's connected in the correct lead polarity. One way works, other way not.
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