I think i killed it Toshiba 40L1333DB

[alerton]

Re: I think i killed it Toshiba 40L1333DB

Can u test this again with the legend disconnected please what's the voltage (everything connected again apart from the led connector )
Did you test the leds before reassembling?
I always thought 121v from the psu is either still an open led or a faulty power supply ?

i tested each strip of led with a 27v supply but not all together as i dont have a power source big enough. and i get the same 121v with the led connected and disconnected and with the main board connected or not too.

happy new year btw and thanks for your patience and help.

[nomoresonys]

Re: I think i killed it Toshiba 40L1333DB

Can test your meter by measuring the voltage of a new battery, 9 volt, 3 volt, 1.5 volt etc.

[alerton]

Re: I think i killed it Toshiba 40L1333DB

Can test your meter by measuring the voltage of a new battery, 9 volt, 3 volt, 1.5 volt etc.

thanks but im pretty sure the meter is reading ok, i tested it on about 6 various known voltages ranging from 1.5 upto 240 and everywhere in between and always spot on but thanks anyway.

[CapLeaker]

Re: I think i killed it Toshiba 40L1333DB

I am not trusting your meter at this point.

[alerton]

Re: I think i killed it Toshiba 40L1333DB

I am not trusting your meter at this point.

fair enough. somewhere at work i think we still have a very old avo analogue meter if it hasnt been binned i will try dig that out and double check again, this will be the 3rd meter i have tried

[R_J]

Re: I think i killed it Toshiba 40L1333DB

How are you measuring the led voltage? are you measuring from led+ to chassis ground?
If that's the case you also need to measure from led- to chassis ground. The led circuit controls the [-] side of the string.

[budm]

Re: I think i killed it Toshiba 40L1333DB

+1

[alerton]

Re: I think i killed it Toshiba 40L1333DB

How are you measuring the led voltage? are you measuring from led+ to chassis ground?
If that's the case you also need to measure from led- to chassis ground. The led circuit controls the [-] side of the string.

led voltage led + to chassis = 121v
led voltage led - to chassis = 24v

that is with everything connected however with the led lead disconnected the led voltage led - to chassis = 10v

[R_J]

Re: I think i killed it Toshiba 40L1333DB

Looks like bad led's in the panel or bad connections somewhere on the strips, You can remove the lcd and disconnect it from the t-con. Then you can operate the tv without the lcd in place and see where the fault is, likely a fault with what you repaired.

[alerton]

Re: I think i killed it Toshiba 40L1333DB

Looks like bad led's in the panel or bad connections somewhere on the strips, You can remove the lcd and disconnect it from the t-con. Then you can operate the tv without the lcd in place and see where the fault is, likely a fault with what you repaired.

would a fault with a led strip cause the total failure of the tv? before i started the set did turn on just without the backlights but now it wont turn on at all not even the front panel led flashing?

i shall have another look at the lcd strips and might end up replacing 1 or 2. i was a little dubious about 1 of the repairs as it was the first led in the strip and i didnt have much space to make the repair but it did seem ok when powered with 27v.

there is a place locally who have some led strips but they dont have the 'type B' i need they have 'type A' and 'type C', would you know what is the difference and are they interchangeable? they all look the same to me.

thanks for your input / advice

[R_J]

Re: I think i killed it Toshiba 40L1333DB

You mean the tv won't turn on at all? I would doubt you would have any led voltage if the tv was not turning on.
Check that you have +5V_STB standby voltage to the main board and then check if you get ST_BY (power supply on) voltage (on the plug) from the main when the power button is pressed. There should also be a BL_ON-OFF line that tells the power supply to turn the backlights on or off

I don't know what the different led strings are, could be different number of led's per string, different plugs?
Maybe some pictures of the panel with the led strips (lcd removed) might help

[alerton]

Re: I think i killed it Toshiba 40L1333DB

You mean the tv won't turn on at all? I would doubt you would have any led voltage if the tv was not turning on.
Check that you have standby voltage to the main board and then check if you get PS on voltage (on the plug) when the power button is pressed.

I don't know what the different led strings are, could be different number of led's per string, different plugs?
Maybe some pictures of the panel with the led strips (lcd removed) might help

yes theres power to the main board etc but before i started the tv worked in every way except the backlights (could see the picture on screen with a flashligt and sound was ok) but now there is nothing not even the front panel led.

the led strips all have 9 individual leds and all have the same spacing so basically they all look identical .

[R_J]

Re: I think i killed it Toshiba 40L1333DB

Whe you repaired the led's did you remove the cables from the t-con board? check if they are connected properly, On the t-con board there should be a fuse near the lvds cable, check the voltage on both sides of the fuse. Other than that I don't know what you may have done that caused the problem.

[alerton]

Re: I think i killed it Toshiba 40L1333DB

Whe you repaired the led's did you remove the cables from the t-con board? check if they are connected properly, On the t-con board there should be a fuse near the lvds cable, check the voltage on both sides of the fuse. Other than that I don't know what you may have done that caused the problem.

thanks for the pointers, will have another look tomorrow, i was going to check it over again today but didnt really have the energy after my chemo this morning.

in reality im not sure if i want to spend much money on this thing, time is not an issue, i only started messing with it because i had it given and to help pass some time whilst im forced to have so much time off work. who knows i might get a sudden burst of energy again tomorrow

[alerton]

Re: I think i killed it Toshiba 40L1333DB

Whe you repaired the led's did you remove the cables from the t-con board? check if they are connected properly, On the t-con board there should be a fuse near the lvds cable, check the voltage on both sides of the fuse. Other than that I don't know what you may have done that caused the problem.

actually thinking back now the power stopped working whilst i still had the screen stripped. after i finished the repairs to the leds i tried and failed to get the tv to turn on just so i could see all the leds lit up. im not sure but im assuming that i managed to short something while repairing the leds.

[petehall347]

Re: I think i killed it Toshiba 40L1333DB

check voltage at front panel led ...

[alerton]

Re: I think i killed it Toshiba 40L1333DB

check voltage at front panel led ...

well bugger me, i just went to check the voltage at the front panel led as you suggested and guess what............ plugged the tv in and it worked streight away, screen lit, sound working, remote working and everything. that is truly weird it was dead as a dodo yesterday, i didnt even go in that room today until just now and the thing fired up instantly. scared the hell out of me to be honest. anyone got an explanation for that?

[petehall347]

Re: I think i killed it Toshiba 40L1333DB

well bugger me, i just went to check the voltage at the front panel led as you suggested and guess what............ plugged the tv in and it worked streight away, screen lit, sound working, remote working and everything. that is truly weird it was dead as a dodo yesterday, i didnt even go in that room today until just now and the thing fired up instantly. scared the hell out of me to be honest. anyone got an explanation for that?

was magic ... may or may not last though ...

[alerton]

Re: I think i killed it Toshiba 40L1333DB

was magic ... may or may not last though ...

i know, i hate a mystery but at least it proves i managed to fix the led strips ok, i never had the screen light up before so maybe im not 'quire' as useless with the soldering iron as i first thought lol but as you say we will just have to see if it lasts, not sure if i dare turn it off again now, i did turn it off once and back on just to see if it was a total fluke and woo hoo it came back on.

[budm]

Re: I think i killed it Toshiba 40L1333DB

Turn down the backlights level to as low as you can to extend the life of the LED's.