Toshiba 50L7300A turns on then blue screen

[Woollyentity]

I have a second hand Toshiba 50L7300A which, when plugged in, turns on and displays the Red Toshiba logo, but then displays a bright blue screen.
I understand this may be a problem with the main board (32L4300 rev 1.02a) but I'm not sure, and they're very difficult to find now anyway.
I tried updating the firmware - the USB flashes a few times when plugged in, then nothing happens and the blue screen is still all I get.
I also have no remote for this TV.

Video of the problem:
imgur.com/a/wdqRLEI

If you've heard of anything similar please let me know what I can try.

Thanks

[R_J]

Re: Toshiba 50L7300A turns on then blue screen

I suspect it is a bga problem on the large ic, try heating it with a hot air gun and see if that helps.

[notallbad]

Re: Toshiba 50L7300A turns on then blue screen

what process are you using to update the fw?
where was the fw from and what is it named and how big is the file.

Sounds like what my blaupunkt is doing after I buggered the fw settings, see my most recent post.

logo. bluescreen, unresponsive to remote and keypad, turns off after 1 minute

can you get the nenu to appear if really quick after the logo goes off???

[Woollyentity]

Re: Toshiba 50L7300A turns on then blue screen

I suspect it is a bga problem on the large ic, try heating it with a hot air gun and see if that helps.

Maybe I'll try that

[Woollyentity]

Re: Toshiba 50L7300A turns on then blue screen

what process are you using to update the fw?
where was the fw from and what is it named and how big is the file.

fw downloaded from a site I found it on, can't remember which site but the download came with instructions as well. The version is v7.1.68.07.01.1. The instructions seem to have been issued by Toshiba so I followed them. Basically just formatted a USB, then put the .fwu file on it. Then I powered the TV off, inserted the USB, pressed and held volume down button, powered the TV back on, at which point the upgrade was supposed to automatically begin on the screen, which it didn't.

can you get the nenu to appear if really quick after the logo goes off???

Haven't tried that. As I said I have no remote but I can try the button on the TV?

[notallbad]

Re: Toshiba 50L7300A turns on then blue screen

Perhaps. forget about fw upgrade for the time being, you could be getting yourself into deeper waters.
The usb flashing a couple a couple of times from power on is normal, try it with a blank usb stick, probably results will be the same! It is possible your supposed to hold vol down or press '0' on the remote whilst powering it up whilst usb with fw is in the usb port.
I'm guessing the tv was in this condition when you got it so you don't know the history, possibly it was a fw upgrade that broke it???
Check all voltages on the power board, if you have no meter or not confident enough just disconnect the backlight power connector to see if tv remains on and responsive to keypad
then you could also try disconnecting the t-con for comparitive results
(always connect / disconnect with power OFF! and after 20-30 secs to allow residual power to dissipate first)
Get yourself a usb-uart device, about £4, to see if you can at least get a response from the tv using putty or similar terminal on your pc

[Woollyentity]

Re: Toshiba 50L7300A turns on then blue screen

Yeah the TV was like this already.
I have a multimeter and I'd like to learn to be able to check voltages but definitely not completely confident at the moment.
I could try disconnecting the backlight although the TV hasn't been responsive to anything and I have no remote.
Is the T-con the other of the three largest PCBs after the main and power boards?

Also never heard of the USB-UART but interesting.

I only intend on using the TV as a big monitor to watch movies played on my laptop anyway. Not sure if that changes much. I appreciate all the help though, I'll let you know once I've had a chance to try some of this.

[nomoresonys]

Re: Toshiba 50L7300A turns on then blue screen

Try test #3 below, try to do it just as instructed, #2 is a video demonstration of testing.

[notallbad]

Re: Toshiba 50L7300A turns on then blue screen

Better to remove the rear panel and take photos of the boards and post them here.

[nomoresonys]

Re: Toshiba 50L7300A turns on then blue screen

Be VERY CAREFUL when working on the HOT/DEADLY side of the powerboard.

[Woollyentity]

Re: Toshiba 50L7300A turns on then blue screen

can you get the nenu to appear if really quick after the logo goes off???

Tried it, held it down, pressed rapidly, at different intervals, startup happens the exact same as in original vid. I was using the button under the volume buttons, not even sure what that is but I assumed it had the most to do with this. Also the top power button doesn't work at all so is it possible the buttons just aren't connected at all?

Removed the rear panel and took a bunch of photos.
https://imgur.com/a/dLyCKcg

Couple of reminders:
- I have no remote
- Haven't had any response from the TV whatsoever other than the original video when I plug the TV in
- Power off button on the TV itself doesn't work either, could all the buttons just be disconnected?

Thanks again for all your help. If the photos don't reveal anything interesting I'll see about some of the testing methods you guys are talking about

[notallbad]

Re: Toshiba 50L7300A turns on then blue screen

Your 'mystery' board is a wireless card so you can forget about that one and associated cables during testing.

The board at the top left is the led driver board.

You know which one is the power board, looks good from photos, nothing obvious I don't think. I'm assuming thats just glue around the capacitors (largish cyclindrical shaped with markings like uF and V) holding them to the board and there not leaking. Cant see any bulging!

And of course your main board to the right.

There will be another board under the metal shield at the bottom, this is the T-con which drives the display panel. Its under the tv stand mounting plate. Add another photo of this board.

On the main board there are 3 cables on the top left corner, the middle one looks like its not properly seated?
Whilst your at it check all other connectors are seated properly

On the keypad its power on / off at the top, then vol up, then vol down, then last one is for 'input source' (short press) AND 'menu' select (long press) The vol buttons are then also used for navigating the menu options and the source/input button used to select the option.

Also list the board part numbers and the panel label etc.. not visible from photos.

[PopescuFanel]

Re: Toshiba 50L7300A turns on then blue screen

I assure you it is a FW problem. I had the same symptoms in another Toshiba model.
Make sure the FW belongs to the model, do not update with the wrong FW !

[notallbad]

Re: Toshiba 50L7300A turns on then blue screen

Yh, I'm convinced its fw too, hence recommending not to do a fw update until we can establish board and panel details.

[nomoresonys]

Re: Toshiba 50L7300A turns on then blue screen

That should be the firmware if there's instructions try to follow them exactly: https://support.dynabook.com/support...ext=1200016427

[Woollyentity]

Re: Toshiba 50L7300A turns on then blue screen

Yeah power board looks fine visually, that is glue under the capacitors, nothing obviously out of place.
Checked the connectors too, all seem to be seated properly.

Additional photos here, including T-Con and back panel info:

https://imgur.com/gallery/OrchEsT

List of details:

TV Model - 50L7300A
Power board - N255A001L (or "N12-225P1A"? Visible under barcode in photo of PB)
Main board - 32L4300 Rev: 1.02A
LED Driver board - L50086-2EA
T-Con board - V420HK1-CS5


@nomoresonys that's the same FW I've already tried, version and all. Maybe I was doing something wrong, we'll see.

[nomoresonys]

Re: Toshiba 50L7300A turns on then blue screen

Try another thumb drive if you have one, sometimes they are not compatible.

[notallbad]

Re: Toshiba 50L7300A turns on then blue screen

Also remember to format the usb stick first, fat32.
And be sure the fw file is the only file on the stick in the root i.e not in a folder.
Might sound silly but is it a .zip file you have that needs unzipping first?

[Woollyentity]

Re: Toshiba 50L7300A turns on then blue screen

Is exFAT okay? I googled and apparently it encompasses FAT32 and others or something.
Otherwise I can try a different flash drive.

I assume the single file in question is the .fwu file also

[nomoresonys]

Re: Toshiba 50L7300A turns on then blue screen

Sure, try another flash drive.