Very Nice Toshiba 46L5200U1 Strobe Effect

[Michale32086]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

It does sound like LED's problem.
LED driver board: You have 4 LED strings, each LED string Cathode is connected to one of the 4 the PWM controlled MOSFET's (Q101 ~ 401), you can check the Voltage on the big tab of each MOSFET to see if they are all about the same or not, the one with bad LED string should show different result.
The PWM dimming signals are from the T-CON board via CN002 connector on the LED driver board, there are pin names printed right by the connector.

Awesome.. Let me check that... Get right back to ya..

[Michale32086]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

OK With the LEDs working, I get 13.xV on all 4 Mosfets...

1.4v on EX_DIM

3.5v on INT_DIM

3.2v on 3D_PWM

0v on 3D_ENA

That is with the backlights working fine..

When I crank up the BACKLIGHT setting and the backlights shut down...

EX_DIM goes to 2.2

MOSFETS go to 0v

All the others stay the same..

[budm]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

OK With the LEDs working, I get 13.xV on all 4 Mosfets...

1.4v on EX_DIM

3.5v on INT_DIM

3.2v on 3D_PWM

0v on 3D_ENA

That is with the backlights working fine..

When I crank of the BACKLIGHT setting and the backlights shut down...

EX_DIM goes to 2.2

MOSFETS go to 0v

All the others stay the same..

OK so when the LEDs are on and when it goes off what Voltage do you get on the connector CN003 pin 1 which is for V+ that goes to the Anode of all LED strings.

[Michale32086]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

OK When the LED strip is working, CN003/1 settles at around 101v....

When I crank up the BACKLIGHT setting and the LED strobes then goes off it goes down to 10.72

[budm]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

It looks like the BL-ON (ENA pin 12 of CN001) signal may have gone away.
Also check to see what feeding Voltage to CN001 pin 1 ~ 5 is, I expect it to be 24V for feeding the LED driver board.
https://www.badcaps.net/forum/attach...7&d=1544129624

[Michale32086]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

With the LED strip on and working fine...

OK ENA pin12 is 3.25v...

1-5 on CN001 is 24 v...

Note to self.. Shorting pin 5 to pin 6 on CN001?? NOT a good idea...

OK With the LED strip shut down...

Voltages are the same.... I didn't short pins 5 and 6 this time

[budm]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

So some how the Boost converter circuit goes into shutdown output drop down to 10V even though the ENA (BL-ON) is still present, you just have to look deeper to see of the 24V gets all the way to the boost converter inductor l001/ MOSFET or not, check the solder joints of the inductor legs, C043, DRV test point, etc. and also look up the spec sheet for that LED driver IC.

[Michale32086]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

What's the part # of that converter inductor??

So, yer thinking it's more of a driver board problem and not the LED strip??

[budm]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

L001

[Michale32086]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

Hokay.. I'll check those.. Calling it a day here..

Thanx a bunch for the help... I feel a lot further along than I was this morning.

[wel2253]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

My 46L5200U1, no picture (except with) flashlight, it has sound. Is this also the led strip?

[nomoresonys]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

Your symptoms are different wel2253, If you have a multimeter try test #3 in my signature, #2 is a demonstration, try to do and report just as instructed. That test is on the cold side of the powerboard, as always BE VERY CAREFUL if working on HOT/DEADLY side of powerboard.

[wel2253]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

Pins 19 BLON ON 3.28v, OFF 0V
15 DIM ON 5V, OFF 5V
14 ACD ON 5V, OFF 5V
13 PQWN ON 5V OFF 5V
10-12 5VCC, ON 5V OFF 5V
8-9 12VCC, ON 11.8V OFF 0V
5-7 GND
3-4 12V, ON 11.81 OFF0V
1-2 GND

[nomoresonys]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

Those look good, first guess is faulty led/s or connection in backlight circuit, which is the case in many strobing situations.

[wel2253]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

Thanks for your help! I am new to this site, what is the best way to see your replies? Yesterday when I logged on - it was there on the screen; today I found it by luck.

I can't seem to find anyone who has the led strip 2012SGS46 - LJ64-03495A, I have seen it on Amazon, but I don't know if I should trust a Chinese or other site abroad. Anyone you know is trustworthy?

[nomoresonys]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

You can bring up troubleshooting tvs and video sources which is this category and just put a shortcut on your desktop, then you just need to sign in after you click it, unless you stay signed in, then you just click it. You can also get an email when there's a response, you do that in settings, it may be in quick links-edit options, not sure haven't used that feature in a while.

[nomoresonys]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

Maybe a match there: https://www.ebay.com/sch/i.html?_fro...c&LH_PrefLoc=3

[nomoresonys]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

Not sure if those are a match but it does say contact seller if any questions so I would ask to be sure and it also has a make offer button on some of them for some possible dickering.

[nomoresonys]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

One there that looks like a match but it would be coming from China, it looks the same as the others to me, also has a make offer option: https://www.ebay.com/itm/Original-LJ...8AAOSwctxdY7Lz

[wel2253]

Re: Very Nice Toshiba 46L5200U1 Strobe Effect

Thank you nomoresonys!