Toshiba 46xv540ou

[erj7]

First post!

Problem: Startup and operation are fine until about 5-15 minutes. Screen goes black but power remains (audio cuts as well). Power cycling restores the video until about 5-15 minutes.

I was told that I should look for bad capacitors on the power board. I've identified no obviously bad capacitors, but I would like people's help.

Attached are some hi-res pictures I took of the power board, front and back.

Thanks in advance

[CapLeaker]

Re: Toshiba 46xv540ou

We need high resolution, straight shot pictures of the boards.

To me it sounds like you have a main board problem, not a PSU problem. On pic# 1 on the left there is this connector that goes to the main board. Turn the TV on and note down pin name and the DC voltage measured. Same thing again when the TV "acted up". Post that here.

Just for reference: Only because a capacitor "looks" like new, it still can be bad. I just had a few examples of that last week. The best way to check the health of a capacitor is with an ESR meter.

BTW: I think the model number of this TV is: 46xv540u

[Andrew F. Ali]

Re: Toshiba 46xv540ou

I encountered another TOSHIBA LED TV with similar issue that Model was a 55SL412U. The PSU was PK101V2510. I at first thought Main Bd. However while poking around I short cct something and toasted the PSU. I believe I was losing the 24V on the PSU. I bought a new PSU to start over the troubleshooting and to my surprise the TV worked and as far as I know is still working.

[dskall]

Re: Toshiba 46xv540ou

Also Need voltages from connector that goes from power supply board to main board. Will need pin#- PIN DESCRIPTION -Pin voltage in standby-Pin voltage when pushing power button and picture of connector on power supply board.
Format:
Pin# - Pin Description - Pin Voltage standby - Pin voltage power on
1 - XXXXXXX - XXv - XXXv
2 - XXXXXXX - XXXv - XXXv
3 - XXXXXXX - XXXv - XXXv
4 - etc.
Also dcv across one of C1 main caps while tv is on

[erj7]

Re: Toshiba 46xv540ou

Pin No. - Description (from Board) - DCV standby (V) - DCV On (V)
--------------------------------------------------------------------
1,2 - GND - 0.0000 - 0.0000
3,4 - 12VA - 0.0300 - 11.842
5-7 - GND - 0.0000 - 0.0000
8,9 - 12VCC - 0.0300 - 11.842
10-12 - 5VCC - 5.0000 - 5.0360
13 - POWN - 0.0000 - 3.2975
14 - ACD - 3.3620 - 3.361
15 - DIM - 0.0082 - 0.2530
16 - BLON - 0.0000 - 3.2851

C1 while ON: 162.21V

[budm]

Re: Toshiba 46xv540ou

":15 - DIM - 0.0082 - 0.2530" Recheck this dim control Voltage when the backlights are on, 0.25V is too low for the backlights to be on.

[erj7]

Re: Toshiba 46xv540ou

Guys..

First of all thanks for diving in. Secondly I think I may have shorted the power board after doing this...

":15 - DIM - 0.0082 - 0.2530" Recheck this dim control Voltage when the backlights are on, 0.25V is too low for the backlights to be on.

Before getting that reading, since the TV was upside down I went to check one of the C1 capacitors on the power board to see if the backlights were on. POP. The TV now refuses to turn. Some minimal burn on one of the C1 leads but the capacitor still holds 162DCV when plugged in.

This just got more interesting. Where should I head to first so the TV can turn back on and we can get back to square one?

Thanks in advance

[dskall]

Re: Toshiba 46xv540ou

Recheck your voltages

[CapLeaker]

Re: Toshiba 46xv540ou

you have to fix the PSU first.

[erj7]

Re: Toshiba 46xv540ou

Just a blown fuse.

The Dim pin reads .25 when the backlights are on. Any thoughts? Inverter circuit?

[CapLeaker]

Re: Toshiba 46xv540ou

well... for shits and giggles, take the DIM pin off (so you don't backfeed), jump BLon to the DIM pin.

[erj7]

Re: Toshiba 46xv540ou

Thanks, I'll do that tomorrow after work. I've talked to a couple techs at the company I work at (I took the TV in and plopped it in the lab), they've seen the problem and conclude it's probably a logic board issue. They say it's likely not worth the effort getting it fixed, just buy a new board.

Unfortunately, I'm having trouble finding a replacement logic board for the 46xv540u. The boards that I find do not physically match the layout that I see on the TV.. (example: https://www.ebay.com/itm/Toshiba-46X...IAAOSwcUBYJfhV)

Where's a good place I can look for replacement boards?

[jetadm123]

Re: Toshiba 46xv540ou

Where's a good place I can look for replacement boards?

You can try shopjimmy.com