Toshiba 46xv645u - No power to the TV at all

[raymondb]

Hello Everyone

A few weeks ago I was watching TV as normal and then I turned it off and came back 20 minute later. It never turned back on after that, no lights came on and no sound from the TV. I left it unplugged for a few days and plugged back in and no result.

I decided to open up the TV and take a look and I replaced two fuses inside but it appeared they were fine and not blown anyway. I tried the TV again and it appears to have no response still. I checked all the capacitors and they are all fine and not showing anything on the top of them. I have taken a picture of the board to hopefully get some troubleshooting steps to get it up and running again!

[newtothis]

Re: Toshiba 46xv645u - No power to the TV at all

TIP : Don't just replace fuses and switch things on, If a fuse has blown it blew for a reason

Have a multimeter?

Can you also unplug the cables that are all close together on your second picture and take a photo directly down so we can read the pin labels please?

[raymondb]

Re: Toshiba 46xv645u - No power to the TV at all

Thank you for the response newtothis! I do have a multimeter I use as a tester, can you let me know what I can try with it?

[newtothis]

Re: Toshiba 46xv645u - No power to the TV at all

meter set to 20vdc and using the TV chassis as ground can you check voltage at POW_PRT and POW_SIG

[raymondb]

Re: Toshiba 46xv645u - No power to the TV at all

I tried it and it does not look like its getting any voltage at all!

[newtothis]

Re: Toshiba 46xv645u - No power to the TV at all

OK 600VAC this time, Can you confirm voltage at both ends of the glass fuse at the input power cable

[raymondb]

Re: Toshiba 46xv645u - No power to the TV at all

I have tested where the power cord is on the right of the fuse and its getting 120volts.

I have tested the fuse by the battery for 750 VAC and it is fluctuating from 15-110 on each side, its not a solid number. Does this mean the board is bad?

[newtothis]

Re: Toshiba 46xv645u - No power to the TV at all

Battery?

[raymondb]

Re: Toshiba 46xv645u - No power to the TV at all

Battery?

I meant the fuse by the power cable, my mistake!

The other fuse at the top has an even lower number also so it sounds like its not getting enough voltage?

[newtothis]

Re: Toshiba 46xv645u - No power to the TV at all

Ok going to need a VERY clear pic of the underside of the PSU

This is of course if you want to repair the PSU and not just switch boards

*** Just to make sure can you probe all pins in the connector that goes to the mainboard to see if there is any voltage present on any of them, Using 20VDC and chassis as ground)

[nicholas1110]

Re: Toshiba 46xv645u - No power to the TV at all

Hi,

Check r850, if it is open, you will need a new one of those and to either clean the contacts of relay sr80 or replace it. I've done many of these now and the dirty contact in the relay causes the fuseable resistor r850 to open at power up. Hope this helps

[budm]

Re: Toshiba 46xv645u - No power to the TV at all

+1:
Read through these threads:
https://www.badcaps.net/forum/search...archid=4807256

[Tdalley111@gmail.com]

Re: Toshiba 46xv645u - No power to the TV at all

I have the same power supply/tv and was hoping to get some advice. I have gone through the above threads. I have checked the Pow-prt and pow-sig points and get 2v and 0v respectively.
I have 5v on 5v1.
Originally I was hearing the relay sr80 clicking, but no longer heraring it.
Any suggestions for next steps would be appreciated.

[dick_barton]

Re: Toshiba 46xv645u - No power to the TV at all

Switch off set. Disconnect the connector going to the main board at the power supply end. Connect the 5V you measured to Pow_On using a 1K ohm resistor. Switch on and measure the other supplies 12V, 18V, 24V and see if they are there.

[Tdalley111@gmail.com]

Re: Toshiba 46xv645u - No power to the TV at all

Thank for the response. I don't see anything labeled Pow_on, assume it is Pow_tv? Got 12v, but nothing on 18v or 24v pins.

[sherrygarris]

Re: Toshiba 46xv645u - No power to the TV at all

Saved another one from the landfill with this great web site! A 52xv645u with the relay / resistor 850 problem.