sickboy
Senior Member
Last Activity: 04-16-2025, 04:52 AM
Joined: 06-22-2015
Location: England
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Sadly, I think the only thing currently capable of decoding the LVDS signal is the dedicated LCD panel designed for that particular TV -
Hi, well today I turn it on and the fault is there instantly. I tried width control and horizontal center controls. Both controls do adjust the overall position and width of the entire screen, including the blank area. I left the TV in the fault state for around 15 minutes, then the TV lost line sync completely. The vertical sync is ok. Could my problem lie within the TDA8304, or the TDA3505 possibly?Leave a comment:
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Thanks Diah, I'll check this when I get it back on the bench tomorrow.
When the TV is working normally (most of the time) the width and horizontal potentiometers operate correctly. The TV only goes into this fault mode occasionally and only for a few minutes.Leave a comment:
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Strange CRT Fault (Sony Trinitron M1410U)
This is a CRT I sold a few months ago and it's came back with this weird issue. It's intermittent, but not a thermal fault, or tap sensitive - just completely random. The right side of the picture completely blanks out (picture is not shifted). The on screen display is unaffected though, so not a fault in the line section. Anyone seen anything like before in a CRT? -
Does it display like this when using a different source than the PC? Also does this effect show when you select the menu, or the smart apps page?Leave a comment:
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Agreed. The tester only supplies a limited current into the backlights. Some backlights will only fail under full current from their proper LED driver circuit.
You could also check for a voltage spike at the LED output plug on the power supply as you turn the TV on....Leave a comment:
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Re: JVC LT-40C750 Backlight goes off after 5 or 10 minutes
No, I had to fit a full new backlight set in the end....Leave a comment:
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Re: The infamous Sony Android Reboot problem
Mohammed at Microtech fixes the boards for around £90 I think.
I've got three of these Android Sony's all with various problems relating to the main board. Sony should really have recalled them or extended the warranty for these issues. These TVs were priced at way over £1000 and they're only lasting 2 or 3 years.Leave a comment:
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Re: Lg 42lb5610
I've had 2 LG models with similar issues. Both of them had the exact same thin black horizontal lines but these were on permanently and all over the screen. More prominent at the top but faded slightly as they went down. I tried replacement tcon and main board but the fault still remained. I put it down to a cof or tab bonding problem in the end.Leave a comment:
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Re: LG 6V LED Backlights
No these are definitely 6v Neil. If I divide the drive voltage by number of LEDS it comes out at 5 point something. I've done dozens of the 3v ones as well and the strips, leds and lenses are easy to differentiate between.Leave a comment:
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Re: LG 6V LED Backlights
Thanks Neil, but if you're working on one strip with all lenses removed (or fallen off), these replacement LEDs are noticeably brighter before fixing any of the lenses into place. They're easily twice as bright as the surrounding original ones.Leave a comment:
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LG 6V LED Backlights
I've been repairing quite a few LG tvs with the usual backlight problems over the past few months. I'm talking about replacing individual leds rather than fitting new strips.
The 3v types are fine, but does anyone else have a problem with bright spots on the screen after replacing the 6v type? This is the type with the thick round lens that also falls off with the slightest touch.
The type of replacement LED I'm using is a 2 watt 3535 6v, which is the most common one on eBay advertised for use with these LG models. At first I was thinking that they just seemed brighter in... -
Re: Hitachi 32HXC01U - No Text in Menus
Thank you very much kind sir, the TV is now working perfectly.
Very much appreciated!...Leave a comment:
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Hitachi 32HXC01U - No Text in Menus
I obtained this TV with a backlight problem which I've fixed, only to find out that although the TV works fine, all menus are blank with no text.
The background for the menu comes up with blank text boxes, and you can navigate these boxes with the remote, and I even managed to tune the TV in so the menu's do work, it's just that there's no text in them.
Is there a way to factory reset the TV? I've tried menu 4725 but the TV just restarts when I do this. Any help greatly appreciated! -
Re: Help Diagnosing Backlight Voltages (JVC LT-50C550)
Update....
Decided to dismantle to screen to check the LEDS and managed to tear one of the tab bonds by accident... TV is now junk.
Just for the record though I went ahead and tested the strips, and every single one of them had at least 1 led not lighting up, some had as much as 4 or 5 failed ledsLeave a comment:
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Re: Help Diagnosing Backlight Voltages (JVC LT-50C550)
Hi sorry for the delay. There's no change with either one of the plugs disconnected, still spikes at 138v then settles down to 95v
Does this indicate that the supply is running correctly?...Leave a comment:
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Re: Help Diagnosing Backlight Voltages (JVC LT-50C550)
Thanks guys, I won't have access to the TV again till tomorrow but will let you know. Appreciate the advice!Leave a comment:
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Re: Help Diagnosing Backlight Voltages (JVC LT-50C550)
Anyone?Leave a comment:
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Re: Help Diagnosing Backlight Voltages (JVC LT-50C550)
Brilliant, thanks Neil, so does that mean with each of my strings boosting to 138v, then settling back to 95v that my power supply is working correctly and I have an open or short circuit LED?
I usually just see no backlight and go straight for opening the screen and testing the led strips, but I'm trying to be a bit more methodical about it.Leave a comment:
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Help Diagnosing Backlight Voltages (JVC LT-50C550)
Wondering if anyone can help me understand the diagnostic process when deciding if the backlight supply is faulty or the backlights themselves.
This is a JVC LT-50C550 which uses a TV5001-ZC02-01 power supply. The symptoms are just a brief flash of backlights at switch on.
Voltages at switch on both white wires (to chassis ground) spike at 138v then settle down to 95v. Voltage on both red wires (to ground) are 45v.
Strangely there is zero volts when measuring between white & red wires on either or both pairs. Can anyone give me an idea what's going...
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