Toshiba 32AV500U No Picture, but responds to remote

[TechGeek]

I received this TV today in nonworking condition. The issue is that you would plug the TV in, turn it on, and the display would do NOTHING. Not even power up the backlight. I took the entire thing apart, and there's no bad caps or loose connections. I put it back together, and put batteries in the remote. It is responsive to commands from the remote, like volume up/down, and power on/off. I don't know how to change inputs on the thing, because of no display. I have tried the light trick, but either I'm doing something wrong, or the LCD is gone. I can't see anything. Can anyone please help? Thanks!

[budm]

Re: Toshiba 32AV500U No Picture, but responds to remote

So the backlights are not working, the next step will be up loading good clear pictures of the whole back side of the TV showing all the boards.
You will need to find out if the inverter board is getting the bl-on and the dimming control signals or not.

[TechGeek]

Re: Toshiba 32AV500U No Picture, but responds to remote

I guess the "bl-on" signal powers up the backlights and the next one is self-explanatory?

[budm]

Re: Toshiba 32AV500U No Picture, but responds to remote

I guess the "bl-on" signal powers up the backlights and the next one is self-explanatory?

Correct.

[TechGeek]

Re: Toshiba 32AV500U No Picture, but responds to remote

Well, sorry for the long delay. I took the TV apart, and took photos of the boards as I disassembled the TV. I'm uploading the photos through my slow mobile data connection on my phone, so photos are coming later.

[budm]

Re: Toshiba 32AV500U No Picture, but responds to remote

Doing the search on badcaps.net using 'Toshiba 32AV500U'
https://www.badcaps.net/forum/search...archid=6027351
Lots of threads come up about no backlights, so you may want to read those threads.

[TechGeek]

Re: Toshiba 32AV500U No Picture, but responds to remote

Error: "Sorry- no matches. Please try some different terms."

[TechGeek]

Re: Toshiba 32AV500U No Picture, but responds to remote

Okay, here are the requested photos.

[diif]

Re: Toshiba 32AV500U No Picture, but responds to remote

Error: "Sorry- no matches. Please try some different terms."

Try again, there are several results.

[Diah]

Re: Toshiba 32AV500U No Picture, but responds to remote

Okay, here are the requested photos.

here you are, attached the service manual for this set, go head to page 11.

[TechGeek]

Re: Toshiba 32AV500U No Picture, but responds to remote

How would I go about troubleshooting the master and slave inverter boards? I've already tried unplugging slave and leaving the master board plugged in, and reversing that configuration. Nothing has helped so far.

[budm]

Re: Toshiba 32AV500U No Picture, but responds to remote

OK, so it uses Master/Slave inverter boards set up, so there is fuse on each of the inverter board so you need to find out if you do have 24VDC at BOTH ends of the fuses using chassis as the GND ref. for the meter when TV is turned on.
Per service manual page 9, connector P202 pin 12 is the BL_ON (ON/OFF).

[TechGeek]

Re: Toshiba 32AV500U No Picture, but responds to remote

Voltages are:
Master:
Before fuse: 24VDC
After fuse:24VDC
Slave:
Before fuse: 24VDC
After fuse: 2.2VDC

[budm]

Re: Toshiba 32AV500U No Picture, but responds to remote

Voltages are:
Master:
Before fuse: 24VDC
After fuse:24VDC
Slave:
Before fuse: 24VDC
After fuse: 2.2VDC

You need to check the Power MOSFETs on that SLAVE board.

[TechGeek]

Re: Toshiba 32AV500U No Picture, but responds to remote

How?

[budm]

Re: Toshiba 32AV500U No Picture, but responds to remote

Get the P/N of the MOSFETs, then search for the spec sheet to learn what the pin of the MOSFETs are and then test the RESISTANCE between Source pin and the Drain pin to see which one is showing really low resistance (<100 Ohms).
BTW, that big SMD IC will usually go bad too.
http://www.ebay.com/itm/Toshiba-HIU-...3D172005301978

http://www.shopjimmy.com/catalogsear...ult/?q=HIU-813

Toshiba HIU-813-M (HPC-1655E) Backlight Inverter Master
Toshiba HIU-813-S (HPC-1655E) Backlight Inverter Slave

[TechGeek]

Re: Toshiba 32AV500U No Picture, but responds to remote

MOSFET 3 has failed. 18 ohms.

[ReeceyBurger123]

Re: Toshiba 32AV500U No Picture, but responds to remote

Also check the controller IC ! Seen alot of them blow up check the VCC to ground it can make the mosfet show up shorted if its bad.

Image showing the same IC that I had to replace it was making the mosfet show up as shorted but the fet was fine and it blew the fuse, the controller was the cause:

[TechGeek]

Re: Toshiba 32AV500U No Picture, but responds to remote

Is that on the single-board TVs?

[ReeceyBurger123]

Re: Toshiba 32AV500U No Picture, but responds to remote

Both master and slave inverter will have that Ic I can see it in the picture above the fets.