Toshiba Regza 46xv645u won't turn on, blinking power led

[Paddy707]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

Budm, I missed your second post from earlier, hence the redundant information i posted.
I followed your suggestion and disconnected the T-Con board from the Main board but nothing changed.
The backlights don't flash or come on at all. Is there a way to confirm they are still good and the LCD?
Is it definitely the Main Board? If so I could try changing it.

[Paddy707]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

I have not been able to find a service manual for this TV but did get one that shares the same boards and layout (power board in the manual is not an exact match), though it does not have any schematics. From following the troubleshooting guide it looks like it is probably the Main Board or the firmware.
I was going to try re-installing the firmware first, but I could not find a copy of the latest firmware anywhere. If anyone has Toshiba firmware versions 2009XV645045 or 2009XV645046 it would be really helpful.

[Paddy707]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

Here is the updated voltage readings showing the pin numbers to match the manual

[dick_barton]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

Looking at the attached page from the pdf I would think that Power_Protect should fall towards 0V when out of standby.


Edit.
What led(s)/colour(s) is blinking?

Mode 20 Power on Standby Led = Red Blinking, Timer Led Off = Power Protect Error

[Paddy707]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

There are two LEDs on the front of this set. One is titled "Power" (I presume STandby?) and the other "On-Timer".
The 'Power' LED blinks green in series of 3 blinks repeated. It seems to correspond to Mode 18 of the LED indications chart

[dick_barton]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

If that's a bootup problem can you try freezing the EEPROM on the main board to see if the set will boot up.

[Paddy707]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

Hi Dick_Barton, how does one "freeze the EEPROM" and where is the EEPROM? on the board?

[dick_barton]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

Freeze the eeprom using a can of freezer spray or a can of compressed air held upside down.
I don't know which chip is your EEprom but hopefully someone on the site can advise you.
What is the number on top of IC112?

[Paddy707]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

Numbers on top of IC112 are: 930 761Y and a symbol that looks like Microchip Technology or Arizona Microtek

[dick_barton]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

If you can read the tops of normally an 8 pin IC and google them to see if any of them are an EEPROM or SPI chip and that will be the one.

[Paddy707]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

I'm not having any luck finding info on google, it just returns lots of sales info that I don't understand.
Here are the IC numbers
IC161 = D051A 9T08 - I think this is a voltage regulator
IC160 = 935 665A
IC506 = 558E 09F1
IC512 = DX095M
IC921 = Z1017AI ZD9T14
IC901 = Z1094DI ZA9V21
IC931 = X2367DNE 96728587 MPSP32
IC770 = 935 761A

[dick_barton]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

These are the only ones I could identify.
IC512 = DX095M Low Power-Loss Voltage Regulator
IC921 = Z1017AI ZD9T14 3.3V/3A Buck Regulator
IC901 = Z1094DI ZA9V21 3.3V/5A Buck Down Regulator

Maybe someone else help to identify the part.

[Paddy707]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

SOLVED!

Good news, I managed to find a copy of the firmware 200946xv645045 through information on Tomsguide.com and after installing it, the TV works again. So far (1 hour) with no issues. Just before this issue arose I had connected a new antenna to the TV (a China made version with amplifier) and that must have sent a signal or voltage that knocked out the firmware on the main board somehow? Anyway, there obviously was no hardware problem which I was only able to determine with the service manual.
I really appreciate all the help and resources I found on this site that eventually led me to the solution. Saves me a lot of cash and saves a TV going in the landfill (I was this close to dumping it - I am indicating a very small distance).
I found Toshiba less than helpful in my search for the solution. They perhaps prefer to force me to buy a new TV than help me fix the one I have, but instead it just ensures I'll never buy from Toshiba again.
Fingers crossed this solution lasts and the problem does not recur.

[dick_barton]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

Well that's good news. Perhaps you could post a link to Tom's firmware on this thread so as that anyone else with a similar problem doesn't have to trawl to find it.

[Paddy707]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

2009XV645046 firmware works for any XV645U model but may need setup adjustment - see technical bulletins for instructions.

The firmware installation instructions are on the last page of the service manual 52XV645U or 40XV645U. Also attached are some bulletins with helpful information. Hope this helps others with similar problems

[budm]

Re: Toshiba Regza 46xv645u won't turn on, blinking power led

Good job finding the cause of the problem and thanks for the follow-up and the firmware.