Toshiba LED TV, blank screen

[Carmine JP]

Re: Toshiba LED TV, blank screen

Cut lead

[Carmine JP]

Re: Toshiba LED TV, blank screen

Cut lead again

[budm]

Re: Toshiba LED TV, blank screen

Well I cut the lead that goes to pin 15, and the problem is still there. Any assistance would be GReAT

Can you please report the DCV Voltage readings of all the pins?
BTW, if the BL-ON (pin 16) is not present, removing pin 15 (dim) is not going to make backlights come on.

[Agent24]

Re: Toshiba LED TV, blank screen

For future reference, it is much better if you cut the flexible wire on the plug rather than the pin on the socket - wires are much easier to join back together again.

In this case you will need to get a whole new socket if you wished to rejoin them.

[tibimakai]

Re: Toshiba LED TV, blank screen

There is still no remedy, for this problem?
There is a TV on CL and I'm not sure, if I should pick it up or not.

[tom66]

Re: Toshiba LED TV, blank screen

There is still no remedy, for this problem?
There is a TV on CL and I'm not sure, if I should pick it up or not.

If you're not prepared to take the risk then you should probably avoid it. LED TVs are proving real hard to fix due to LED array failures and LCD panel faults. I've also found that, at least around where I live, they don't command that much of a premium over conventional LCD TVs, so they're not worth much to me either.

[vinceroger69]

Re: Toshiba LED TV, blank screen

Hard to resell led tvs around my area too, argos the minute are doing 32in hd ready proscan sets £139.00 so trying to sell any repaired sets for a resonable mark up is hard imo at the minute.

[tibimakai]

Re: Toshiba LED TV, blank screen

I have realized that already, that is why I start repairing other type of devices as well.
But still, if I find a nice TV, I can still make a little bit of money, but for sure not like in the past.

[TechShui]

Re: Toshiba LED TV, blank screen

FW update - well, finally got the FW update working... definitely helped that I could see the screen in order to select 'yes'... learned something maybe useful to others... initially used a usb hanging around... didn't work. It was 8GB and formated NTFS. Found an older usb, 512MB (website said 256MB min) and formatted FAT32. bingo, worked like a champ. results? time will tell, although I have to now figure out how to get the channels happy... some are proper aspect ratio for 46", and other channels seem stuck on low quality with view not going out to sides... will keep all posted, thanks MDLuffy

Where did you download the firmware update from?

[james1095]

Re: Toshiba LED TV, blank screen

A very common cause of this symptom in these sets is failure of the LEDs themselves. They fail shorted which is unusual for LEDs and this causes the inverter to shut down. Unfortunately the LED strip is buried inside the panel and is a real pain to access. You can test easily though, the strip is wired as four series strings of 16 LEDs with a common anode and there are test points near the connector on the inverter. Power on the set while watching the voltage between common and each of the four cathode test points. It should show about 100VDC on each one, if one or more is significantly lower, you have one or more shorted LEDs in the backlight strip.

It isn't unique to Toshiba, some other TVs use the same Samsung LCD panel.

[alfredomfr1]

Re: Toshiba LED TV, blank screen

I have a Toshiba 46L5000U with same problem: turn on, Toshiba logo for 1 second and dark screen after that.
I disassemble the panel and found it 2 led shorted.
Ordered in ebay for 24.99, will post again when arrive.

[alfredomfr1]

Re: Toshiba LED TV, blank screen

LED received and installed, LED strip ok now, but still Toshiba logo for 1 second and dark screen.

[Agent24]

Re: Toshiba LED TV, blank screen

Did you verify they all light up even if for just one second? Are you sure you did not miss any shorted or open LEDs?

[budm]

Re: Toshiba LED TV, blank screen

Did you replace the LEDs or the LED strip?
Do you also see the DCV at the DIM goes up to >3V and then drops down?

[alfredomfr1]

Re: Toshiba LED TV, blank screen

I replaced 2 shorted LED and yes DIM goes up to >3v and then drops down to 0.2v

[alfredomfr1]

Re: Toshiba LED TV, blank screen

You right Agent24 found one more that not light up but is not shorted or open, have same reading that the good ones.

[Agent24]

Re: Toshiba LED TV, blank screen

You right Agent24 found one more that not light up but is not shorted or open, have same reading that the good ones.

If it doesn't light up something must be wrong with it. Maybe it has a broken solder joint or broken\burnt trace? Or maybe it's only failing under load. Try replacing it anyway?

I would assume if that one is not working for whatever reason, then it is the cause of the backlight getting shut down.

[budm]

Re: Toshiba LED TV, blank screen

I replaced 2 shorted LED and yes DIM goes up to >3v and then drops down to 0.2v

Try disconnecting the DIM wire and see if the backlights will stay on.

[tibimakai]

Re: Toshiba LED TV, blank screen

I have the same TV, but it runs for hours and eventually, the backlight goes out.
TV still works, sound is working and with the flashlight, I can see the image.
Installed the firmware from Toshiba site, but did not fix the problem.

[budm]

Re: Toshiba LED TV, blank screen

You can reduce the backlights level to about 75% of max, I was able to keep it running all day, otherwise the backlights will shutdown after about 2 hours.
This one has the PWM control line problem, I disconnectd the PWM line and use the resistor to drop the analog dimming Voltage down to keep the backlights on.
http://s807.photobucket.com/user/bud...?sort=3&page=1