Toshiba Regza 46xv54ou Two Flashes no 24v

[scumdog1221]

I was given this Toshiba 46xv54ou LCD which must have been near the beach here in San Diego because all the fake stainless rusted. When I plug in the tv the yellow standby light flashes 1-2-3 and does that three times then the green power light comes on. I hit the power and the relays click loudly and a nice full picture flashes on (i can see the menu for a sec) then goes out and then flashes one more time and goes blank. You can hear a faint buzz and see the backlights during the flash. No obvious fried or bulged parts. i replaced the charis board because the rust had done a number on it however that didn't fix it. The Tcon and the inverter boards are in fairly pristine condition and I did not take them out so far. I checked voltages on the power boards where they were labeled and the bridge rectifiers. See the diagram I made below. The pin labeled 24v had a zero reading. I took pictures of the power and main boards front and back. Hopefully you all can help me sort this out.

[Diah]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

24 volts related for back light, disassembly it and inspect them you may have open circuit at it.

service manual here http://elektrotanya.com/toshiba_46xv.../download.html

[scumdog1221]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

I've downloaded that manual before and when I open the html file it asks for something called 'zeus' and says it only works with IE6. This is the message:

"The ZEUS ENGINE cannot be located.
This Service Manual requires ZEUS ENGINE.

This might be caused whether the ZEUS ENGINE was not installed successfully or some setting in operating ZEUS Service manual with network environment was incorrect.

Please contact to the nearest TOSHIBA Service Center for further assistance"

Very frustrating and I didn't find much helpful when I googled 'zeus".

[dick_barton]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

I would imagine that the CCFL tube holders have all rusted up as well.

[scumdog1221]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

This is where I'm a real noob. What is the procedure to check the CCFL's? Can I do it by just pulling the inverter board and looking or do I have to go deeper? I apologize for my ignorance. I get the feeling you guys think this may be a compromised CCFL issue and not just a bad component on one of the boards? What would be the reason for the 0 volt reading on the 24V pin? I appreciate your patience folks.

[dick_barton]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

It's not for the feint hearted but here's a video

https://www.youtube.com/watch?v=EO2gHBJCvH0

[scumdog1221]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

Wow. Thank you my friend I'm gonna dive into this and let you know what i find out.

[scumdog1221]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

Well I gotta admit for my first time taking apart a panel that was pretty cool. The video you referred me to was excellent. When I pulled the inverter I noticed some kind of oxidization on two or three of the tabs. What would that indicate? The back of the inverter was discolored on one end of it like it got pretty warm. Picture are below. I took some closeups of the CCFL tubes on the ends. You can see small dark circles. The tube holders looked like they were clean. Would i have test the tubes to know if they're burnt or not? I'm not really sure where to go from here...and still wondering why I have no 24V on the power board. Would the oxidized inverter tabs have anything to do with that?

[budm]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

You should clean off the oxidation on the circuit board fingers and also the fingers that make contact withe board fingers.
You can leave the LCD panel off for now so you can see if the all the lamps lights up when you turn on the TV.

[budm]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

BTW: Power supplies diagrams.

[dick_barton]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

If you see a picture for 1 second or more then you have 24V for the inverter but you say in your first post there is no 24V. Looking at the circuit budm has kindly posted there is a fuse F807. Have you checked it?

[scumdog1221]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

Thank you for the diagrams. Fuses are good. When I check the inverter with the panel off do I need the tcon hooked up?

[scumdog1221]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

Went ahead and hooked up the inverter (after cleaning the tabs) tcon and powered up with the panel off and it came on with a nice bright flash and then one more a couple seconds later just like I described in my first post. The inverter is getting 23.9V from the PE0564 power board (thanks again for the diagrams). On the PE0563 however (see red circle in picture) the 4th pin from the right labeled 24V is still reading 0.

On the PE0564 I checked fuses F801 F820 and F870 and they were good. I could not locate F807. On PE0563 I checked two fuses and they were good.

[dick_barton]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

Can you bend the wires the other way and get a close up photo so I can see the name of the pin is giving 0V.

Sorry the fuse to check was F870 , my error, which you have done.

[dick_barton]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

Have had another look at the missing 24V supply. With the aid of Budm's circuit diagram and looking at your pictures in the first post this is what I have noticed.

There appears to be no connection to 24V since I cannot see any of the components as shown in the schematic on the circuit board, however these components could be on the underside of the board.

Look at picture in post #13

Does it look like the following components have been removed. R8973,D8973, D8974, F897

Maybe someone has attempted to repair it before throwing it?


Edit:
I have just taken a close look at the boards on Shopjimmy and it looks as though these parts for this model are not fitted so I guess the 24V is for another version of this power supply.

[scumdog1221]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

Well this might make you cringe but I took a jumper wire from one of the good inverter 24v pins on PE0564 made sure I had voltage and connected it to the 24V pin in question on the PE0563 and powered on with everything hooked up (no lcd panel) and there was no change. The two flashes as usual. So you think the 24V pin on PE0563 is not used in this version? There are alot of blank component spots on that board and a couple on the PE0564 as well. I don't think anyone tried to repair it previously...curiouser and curiouser as they say...

[dick_barton]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

To be honest I don't believe that 24V pin is connected to anything. The reason being the SMPS gives out 24V and 24INV. The 24VINV supply is running because the lamps come on. The 24V supply is on because it switches on one of the two relays.

So can you post a picture of the connectors with the legends in view so we can see what should be available on the connectors?

[dick_barton]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

What are the legends on the connector on the invertor board?
Can you measure the voltage on each pin?

[scumdog1221]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

ok there are 10 pins hooked up to the inverter right there. If we're using the pic for reference I started at the south end which is hidden under the main board in the pic and got 23.9 on the first 5 going north and 0 on the next 5.

[scumdog1221]

Re: Toshiba Regza 46xv54ou Two Flashes no 24v

There appears to be no legends as to what each pin should be that i can see printed on the board. And the underside is blank.