Toshiba 46xv640uz inverter

[ron321]

Hi, new to this but really like all the help here. 2 yr old lcd developed the no picture, comes and goes, but image is running in the background when using a flashlight to see it. Full sound but picture shows up after varying amounts of time..15 mins to 6 hrs! I see no bad looking capacitors on inverter or power supply board. Do I just pick up another inverter board since this seems the most likely cause or do some testing for say output from power supply to inverter? How? Why is the inverter stamped Samsung? Suprised me a little.
Thanks... from a newbie, the more I see here the more I want to learn!

[PlainBill]

Re: Toshiba 46xv640uz inverter

Hi, new to this but really like all the help here. 2 yr old lcd developed the no picture, comes and goes, but image is running in the background when using a flashlight to see it. Full sound but picture shows up after varying amounts of time..15 mins to 6 hrs! I see no bad looking capacitors on inverter or power supply board. Do I just pick up another inverter board since this seems the most likely cause or do some testing for say output from power supply to inverter? How? Why is the inverter stamped Samsung? Suprised me a little.
Thanks... from a newbie, the more I see here the more I want to learn!

The inverter is stamped Samsung because it (and the LCD panel) were most likely made by Samsung.

A clear, sharp picture of the left hand connector on the inverter might help us help you.

Also, I seem to remember something about replacing the caps on the inverter - don't do that until we have checked some voltages.

PlainBill

[ron321]

Re: Toshiba 46xv640uz inverter

Thanks, this is the left hand connector.

[PlainBill]

Re: Toshiba 46xv640uz inverter

Thanks, this is the left hand connector.

There are two wires going to the real left hand connector. Where do they go?

PlainBill

[ron321]

Re: Toshiba 46xv640uz inverter

They go to the board top center - t-con board?

[PlainBill]

Re: Toshiba 46xv640uz inverter

They go to the board top center - t-con board?

Oy!!!

PlainBill

[PlainBill]

Re: Toshiba 46xv640uz inverter

Let me try this again. The picture of the left connector was excellent, but I see no signs of control lines. I'd like a similar picture of the right connector, and just for luck, one of the narrow connector.

PlainBill

[ron321]

Re: Toshiba 46xv640uz inverter

Right connector and narrow at the inverter.

[PlainBill]

Re: Toshiba 46xv640uz inverter

Right connector and narrow at the inverter.

50% excellent, 50% incorrect, but it doesn't matter.

The connector with the big M (master?) next to it has 4 pins that obviously carry control signals. One of the methods of troubleshooting 'disappearing backlights' problems is establishing if the inverter is turning off, or being turned off. Pins 11, 12, 13, 14 are the control lines. What I would like to see is the voltages on each pin when the backlights are on, and when they are off.

PlainBill

[ron321]

Re: Toshiba 46xv640uz inverter

Hi, long delay. I got ahold of an inverter board for $30, no change at all. Borrowed a fluke and measured on the master inverter connector pin 11 .29v, pin 12 1.11v, pin 13 3.27v, pin 14 1.24v.This was with no picture on the screen. I noticed the 2 large caps on the power supply drop down quickly to 10 or less volts after only 2 minutes of having the set unplugged. Is that normal? They are 220v 860uf and I expected much more voltage present in the caps. I'm not giving up just very cautious, too new to this so thanks for the help and patience.