Toshiba 49L621U

[kristapMA]

Re: Toshiba 49L621U

BE CAREFUL when measuring filter capacitor, capacitors can carry a DEADLY CHARGE long after tv has been unplugged, can check video below.

Thank you for the heads up. I will watch the video when i get ready to measure it..

[kristapMA]

Re: Toshiba 49L621U

Can you redo all these measurement's when the TV is in that fail mode?

you mean when its fully on? After the logo and it turns black?

[nomoresonys]

Re: Toshiba 49L621U

BE CAREFUL when measuring filter capacitor, capacitors can carry a DEADLY CHARGE long after tv has been unplugged, can check video below.

[budm]

Re: Toshiba 49L621U

https://www.badcaps.net/forum/attach...1&d=1524391578
What DC Voltage do you have when measure right between the two legs of the two brown caps (100uF 160Vdc) laying on the side in that LED driver section that is marked with yellow box?

[dick_barton]

Re: Toshiba 49L621U

The initial post indicated that there was audio but no backlights.
The voltages given appear to support that all the DC voltages are up and running as well as Backlight On and Power On signals.
Now trying to establish what the led voltages read on power up to see if there is a led(s) / led driver fault.

[CapLeaker]

Re: Toshiba 49L621U

Can you redo all these measurement's when the TV is in that fail mode?

[dick_barton]

Re: Toshiba 49L621U

+1
I'd agree. If there's a led problem then the analogue meter may well be too slow to measure the peak voltage.

[nomoresonys]

Re: Toshiba 49L621U

Can pick up a digital meter for 10 bucks or so, don't have to have one but they are easier to work with for new operators.

[kristapMA]

Re: Toshiba 49L621U

Place your probe, black to chassis and red to connector pin with meter set to 200V DC range and then switch on the set and note the maximum voltage read by your meter and what it may drop to. Switch off the set and move the red probe to next pin and repeat. There should be a legend giving the pin names of the connector alongside or close by.

1 - 4 down to 3 = VLED1-
2 - 4 to 3 = NC
3 - 4 to 3 = VLED2-
4 empty = NC
5 empty = VLED3-
6 empty = NC
7 empty = NC
8 empty = NC
9 - 1 to 0 = NC
10 empty = NC
11- 1 to 0 = VLED+
12 empty = VLED+
13 - 1 to 0 =VLED+

Other Legend says -
5v1=1.52A
16v2=2.42A
16VA=1.50A
vled=1.005A

Started with 1 being the red wire to the left and moved to the right
Also attached the pic of my meter to make sure i have it set right and am reading it right?

[dick_barton]

Re: Toshiba 49L621U

Place your probe, black to chassis and red to connector pin with meter set to 200V DC range and then switch on the set and note the maximum voltage read by your meter and what it may drop to. Switch off the set and move the red probe to next pin and repeat. There should be a legend giving the pin names of the connector alongside or close by.

[kristapMA]

Re: Toshiba 49L621U

I think you have a led problem. Can you measure the voltages on the connector in the yellow box and note the voltages on each pin at switch on. It may rise quickly and then drop just as quickly.
The legend in the yellow box also says what the led voltage should be but I cannot read it.

should i measure it with the tv on, off or both like before?

[dick_barton]

Re: Toshiba 49L621U

I think you have a led problem. Can you measure the voltages on the connector in the yellow box and note the voltages on each pin at switch on. It may rise quickly and then drop just as quickly.
The legend in the yellow box also says what the led voltage should be but I cannot read it.

[kristapMA]

Re: Toshiba 49L621U

https://www.youtube.com/watch?v=4v8DcqCNG4A testing video, test the connector in post #10 P802, test with tv plugged in that's standby, then turn on tv see if readings change, report readings for both states back here, for example pin one on standby 16 volts, tv on 16 volts or whatever reading you get.

Standby
1 - 0 - 16v2
2 - 0 - 16v2
3 - 0 - 16v2
4 - 0 - gndp
5 - 0 - gndp
6 -0 - 16va
7 - 0 -gnda
8 - 0 - 16v2
9 - 0 - gndp
10 - 5 - 5v1
11 - 0 - acd
12 - 0 -pwon
13 - 0 -blon
14 - 5 - 5v1
15 - 0 - dim

POWER ON

1 - all the way - 16v2
2 - all the way - 16v2
3 - all the way - 16v2
4 - 0 -gndp
5 - 0 - gndp
6 - 0 - 16va
7 - 0 - gnda
8 - 0 - 16v2
9 - 0 -gndp
10 - 5 - 5v1
11 - 3 acd
12 - just under 4 -pwon
13 - just under 4 - blon
14 - 5 -5v1
15 - 3 - dim

When I tested 10 when the tv was on, the lights (LED) flickered on then off..

is this what you were talking about?

[budm]

Re: Toshiba 49L621U

Also please make sure to put down the pin names so we can easily see what each pin is and what Voltage it has in two conditions.

[nomoresonys]

Re: Toshiba 49L621U

Test all 15 pins, the legend/map is to the left, see it?

[nomoresonys]

Re: Toshiba 49L621U

https://www.youtube.com/watch?v=4v8DcqCNG4A testing video, test the connector in post #10 P802, test with tv plugged in that's standby, then turn on tv see if readings change, report readings for both states back here, for example pin one on standby 16 volts, tv on 16 volts or whatever reading you get.

[kristapMA]

Re: Toshiba 49L621U

Ooops... a year and a half! Well that sux. Do you have a muli meter in order to do some voltage tests?

CapLeaker, I have the multi meter but not sure exactly what I need to test?

Edited to add, i saw a video and checked the standby power and it was 5volts so i think that is good according to the video.

[kristapMA]

Re: Toshiba 49L621U

Can you post a clearer image of the section shown in the red box.

Here is an image of what you had in the red box....

[kristapMA]

Re: Toshiba 49L621U

Ooops... a year and a half! Well that sux. Do you have a muli meter in order to do some voltage tests?

My brother is going to let me use his. Once I get that, i will be able to do more, in the mean time I am trying to get an idea of what I will need to test and what I should be looking for.

[CapLeaker]

Re: Toshiba 49L621U

Next month will be a year and a half... So over a year...

Ooops... a year and a half! Well that sux. Do you have a muli meter in order to do some voltage tests?