Toshiba LCD 37RV733 only goes on for a second

[Groen]

Hey guys and gals,

my tv goes on, but just for a second then it turns itself off i guess (screen goes black) and the led light starts to blinking (still green) and the tv doesn't react to anyhting other then the manual power switch on the side. I don't have any experience in fixing a tv, but i hope this problem is something i can repair with the help of you guys. I have looked at the capacitator but they don't seem bulged to me. And looking at the board i couldn't find any brown spots or broken things. If you guys need anything just let me know, i tried to make decent pictures to help locate the problem but i can make more if needed ofcourse. Thanks in advance.

Greetings Groen

[dick_barton]

Re: Toshiba LCD 37RV733 only goes on for a second

A good starting point will be to measure the DC voltages of the pins of the two white connectors giving the corresponding pin names that are given alongside.

[Groen]

Re: Toshiba LCD 37RV733 only goes on for a second

Yeah at the moment i don't have a multimeter, yet, will try to get one this weekend. Got any tips on what to get?

[dick_barton]

Re: Toshiba LCD 37RV733 only goes on for a second

If you want one just for testing this TV then a cheap AC Volts, DC Volts and Ohms multimeter should do the job.

[Groen]

Re: Toshiba LCD 37RV733 only goes on for a second

Ok sorry for the long wait, something else needed my complete attention. Finally i got everything setup, but i don't get a reading, i'm probably doing something wrong. I do have to disconnect the two white connectors because otherwise i can't reach it with the multimeter. I tried the negative (black) on a grounding screw on the chassis and the positive (red) on the disired pin. I've added a photo of the mulimeter i got. Maybe i'm using the wrong settings or something like that. Really sorry about my lack of knowledge.

[dick_barton]

Re: Toshiba LCD 37RV733 only goes on for a second

Set the meter dial to 20V DC (10 O'clock position) and use the right-hand and middle sockets for your meter leads.
Black lead on the chassis is fine and use the red lead to measure the voltage at the connectors.
Switch the TV on. You can use a pin or needle attached to the red meter lead probe using tape to secure it so that you can insert it into the top of the connector where each wire enters so as to get a reading.

[Groen]

Re: Toshiba LCD 37RV733 only goes on for a second

Ok I meassured the two white wires from the two connectors and they gave 11.87V for the left one and 24V for the top one. Should i do all the wires?

[Groen]

Re: Toshiba LCD 37RV733 only goes on for a second

Meassured the other wires aswell and added two pictures for better clarity of what each should do, hope this helps. The colors in the excel file rerpresents the color of the wires and black means there isn't one.

[dick_barton]

Re: Toshiba LCD 37RV733 only goes on for a second

The two connectors have pin numbers at one end and run 1,3,5,7,9 etc along the length of that connector. The other side of the connector marked 2 will be pins 2,4,6,8 etc along that side.
If you could give the voltages of the two connectors PJ90 and P860

I think the reading given in the excel file are in reverse, ie pin 1 is pin 25, pin 2 is 26 etc.

[Groen]

Re: Toshiba LCD 37RV733 only goes on for a second

Thanks for all the help so far! as you said the readings were in reverse, now properly done, i hope.

[dick_barton]

Re: Toshiba LCD 37RV733 only goes on for a second

Most of the supply voltages are up and running. Even though there's no picture do you have sound?
Do the 3 leds on the front of the TV, match any of the flash sequences shown on page 22 of the manual?

What is the label name of pin 24 of PJ90?


Edit
Does the set have a fan and does it run when you power up?
Pin 24 is BL_DET (Backlight Detect)


I think you may well have an inverter fault.

[Groen]

Re: Toshiba LCD 37RV733 only goes on for a second

Hey i think your right about the inverter. I don't seem to get sound working for long. Made two videos of the process, can i link you the google drive share url (dunno) but i'll leave it here. I can't see any fans and don't hear any when the tv turns on. What would be the next step if it is the inverter?


https://drive.google.com/file/d/1muw...ew?usp=sharing

https://drive.google.com/file/d/1gSk...ew?usp=sharing

[vinceroger69]

Re: Toshiba LCD 37RV733 only goes on for a second

inverter or faulty ccfl tube would be my guess too, blinking led i guess is the error hence not reacting to anything other than main power switch

[dick_barton]

Re: Toshiba LCD 37RV733 only goes on for a second

I'm not 100% sure about this but you could try disconnecting PJ90 going from the mainboard to the power supply at the power supply end.

At PJ90 connect a 1K resistor between pin 12 (5V) and pin 13 (Power_TV) this should bring up the 24V and 12V supplies.

Using a second 1K resistor between pin 12 (5V) and pin 21 (BL_On) hopefully will bring on the backlights.