Re: Toshiba 32W3451DB Backlight Problem
Some progress - still awaiting replacement PSU. After recent comments and looking elsewhere however - my thoughts were 'if it is a shorted LED - how can I perhaps simulate things?'
Placed a 3V9 Zener in series with the backlights and retried. Still no obvious 'lights' but now the LED backlighting drive voltage has looked to stabilize - Now RED lead closer to +72V and black line not obviously fluctuating - @ approx. 1.5V
Looks like the load the LED backlighting was placing on the drive was such that it somehow was shutting on/off - but why no backlighting still unclear?
Well that was the case for about 10 minutes now looks to have returned to original state!
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Re: Toshiba 32W3451DB Backlight Problem
This is my initial guess - although I do intend to try a replacement PSU PCB 1st - have been waiting for delivery, hopefully sometime this week.
If it does turn out to be the LED's how do I replace them as I cannot find any real indication of how to take apart the panel bit? I was told by another party that there was detail on 'forums' for this - but I have not seen anything yet?Leave a comment:
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Re: Toshiba 32W3451DB Backlight Problem
I would say leds on this one tbh seen it too many times on these crappy cheap led tvs, if you do find that any of the leds are shorted let me know we have replacement strips for this exact tv.Leave a comment:
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Re: Toshiba 32W3451DB Backlight Problem
If you look @ earlier message that is already there:
At present - there are two connections to the LED(s) and a DVM across this pair indicates something odd - may be pulsed DC of some form.
Red wire LED to chassis approx. +27V DC. Black Wire LED to chassis/0V approx. 1.5/2.5V DC - but again suggests pulsed or something.Leave a comment:
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Re: Toshiba 32W3451DB Backlight Problem
Check the voltage read on those red and black wires going off to the panel - I think that is the LED backlight supply.Leave a comment:
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Re: Toshiba 32W3451DB Backlight Problem
No sure whether this is what you want - but basic overviewAttached FilesLeave a comment:
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Re: Toshiba 32W3451DB Backlight Problem
Pictures so we can see all the boards and how they are connected together?Leave a comment:
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Re: Toshiba 32W3451DB Backlight Problem
If I knew what voltage to actually expect I would be measuring it.
At present - there are two connections to the LED(s) and a DVM across this pair indicates something odd - may be pulsed DC of some form.
Red wire LED to chassis approx. +27V DC. Black Wire LED to chassis/0V approx. 1.5/2.5V DC - but again suggests pulsed or something.
Can I drive the LED's with something else to test them? If so what?Leave a comment:
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Re: Toshiba 32W3451DB Backlight Problem
Have you checked if the power supply is giving the required output voltage for the LED strip (approx 40V?)
I say this because I fixed a similar set with a "VES315" panel (some crap Vestel junky LCD) and the fault was the PSU, shorted diode and FET on power supply dragging 24V down.Leave a comment:
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Toshiba 32W3451DB Backlight Problem
I have a Toshiba 32W3451DL LED backlit TV - panel VES315WNDL-0 with no backlight - fails torch test but all signals etc OK. Actual LED strip(s) [??] not visible as within panel - not sure if PSU (which I assume includes LED driver) or actual LED's - how can I test/determine which and can anybody point me in the correct direction on to how to dismantle the panel gaining access to the LED's please?
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Hi. I have a problem with Asus ROG GA402RK. The keyboard suddenly stopped working along with the kb backlight. I replaced the keyboard and the ITE KBC chip and the problem is still the same. I don't see any passive elements that look damaged. Does anyone have an idea?04-28-2025, 04:30 PM
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hello everyone!
As the title states i am an owner of an LG flatron M2362DP 23 inch monitor Tv. Since i currently use it as a tv i'm posting the problem on the "troubleshooting tvs and video sources" section.
I'm from Greece so English isn't my native language, so please forgive me for any mistakes i make. I have basic knowledge in electronics, and although i have a degree, many things have changed since i finished a 2 year coarse (over 30 years ago). Occasionally i repair easy stuff, mostly things that break at home like appliances.
So i decided to try to... -
hello I have a backlight problem on this TV, if I unplug the cn201 cable the backlight works perfectly and the voltages are 13v if I connect the cn201 cable the backlight goes off and the voltage drops to 12v, I assume it's a motherboard problem, the question is has anyone had a similar problem? I want to understand if the motherboard is repairable or it's not worth wasting time... -
Hello Guys,
I received Toshiba Qosmio X755 that has a charging problem and I'm stuck trying to figure out the problem.
- When battery is unplugged i works without any problem.
- When I plug in the battery after plugging in the charger, it works correctly and the battery is charging.
- When I plug in the charger after inserting the battery, it stops working. ( voltage dropped and consumed 8A, reaching the maximum capacity of my bench power supply for 5 seconds, and stop working after )
Can you help me diagnose the problem? I have attached... -
Hi,
I have a Toshiba LED tv model number 40L2400VQ.
I don't receive the correct voltage at the output to the LEDs.
I disassembled the front panel and checked all leds and they are fine. Then I checked the voltage to the leds on the power board and it flactuate in milivolts.
Tested all caps with esr meter and they are fine.
The diodes are fine and the resistors too.
Where should I concentrate on?
Thanks in advance....
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