Toshiba 32LV67U backlight problem

[hienton2]

Hello . I am working with Toshiba 32LV67U. Tv has backlight in 2 second then black out.I tested every lamp
It shows light. I do not know problem is in lamp or inverter. Inverter has ic SEM2006. I try to defeat protection of this ic but I can not.
I have schematic of this ic. Pin 5(det) pin 8(feedback) pin 10(ovp).

[tom66]

Re: Toshiba 32LV67U backlight problem

You have stable 24V going to inverter?
Is BLON stable?

[hienton2]

Re: Toshiba 32LV67U backlight problem

Yes It has 23.90v and bl_0n 4.51v Tom
all stable

[tom66]

Re: Toshiba 32LV67U backlight problem

Picture of the inverter?

[hienton2]

Re: Toshiba 32LV67U backlight problem

Here is the picture.

[tom66]

Re: Toshiba 32LV67U backlight problem

Any chance you can upload a JPEG? I can't open that file.

[budm]

Re: Toshiba 32LV67U backlight problem

Can we see the picture of YOUR board? And closed up pictures so we can see the labeling at the connector. The picture you posted is low res, not good enough to troubleshoot.

[hienton2]

Re: Toshiba 32LV67U backlight problem

Here is JPEG Tom

[tom66]

Re: Toshiba 32LV67U backlight problem

Again, that is just too small to work with. It needs to be at least twice as big, preferably even bigger.

[budm]

Re: Toshiba 32LV67U backlight problem

I cannot read any printing on the board at all, just remember one important thing, we do not have the board in front of us to look at closely. Just look at the picture you posted, Can you read any labeling on the board, on the components?

[hienton2]

Re: Toshiba 32LV67U backlight problem

Hello Budm and Tom66.Now I try my camera.Just Let me know what I have to do.

[budm]

Re: Toshiba 32LV67U backlight problem

OK, on the inverter transformer, make the bottom left pin as pin 1, so pin 4 is the right bottom. For the top row pins, top left is pin 8, so take the resistance read of pin 8 & 7, 6 & 5. Do the test on all 3 transformers, and report the reading, make sure to tell us if the reading is in Ohm, K Ohms, or M Ohm.

[hienton2]

Re: Toshiba 32LV67U backlight problem

Tranformer left 7&8 1235 ohm 5&6 1240 ohm
center 7&8 1245 ohm 5&6 1245 ohm
Right 7&8 1212 ohm 5&6 1260 ohm

[michael first]

Re: Toshiba 32LV67U backlight problem

Hi, try to short pin 5 to pin 11(gnd) of sem2006.as the transformers seem ok could work.

[hienton2]

Re: Toshiba 32LV67U backlight problem

Hi, try to short pin 5 to pin 11(gnd) of sem2006.as the transformers seem ok could work.

I try to short pin 5 to gnd . no work. Any other pin should I try?
Thanks Michael

[hienton2]

Re: Toshiba 32LV67U backlight problem

I cannot read any printing on the board at all, just remember one important thing, we do not have the board in front of us to look at closely. Just look at the picture you posted, Can you read any labeling on the board, on the components?

Yes Budm . I can read all labels. It is INVST320T.
Today I install another inverter I got it from ebay. TV still black out after 2 seconds flashing. All transfomers of new board have good reading ohm