old Bravia double fail?

[nomoresonys]

Re: old Bravia double fail?

and you followed the firmware upgrade procedure, exactly like it says on the sony site?

[nomoresonys]

Re: old Bravia double fail?

ok lets try this, unplug cable from powerboard to mainboard, plug power cord in, see if theres anything on the display or the backlights come on.

[nomoresonys]

Re: old Bravia double fail?

can you post a picture of the whole back, as to see how everything is connected?

[eccerr0r]

Re: old Bravia double fail?

Yeah saw a YT video of someone doing the upgrade, and it does not behave the same way.
I also disconnected the MB from the inverter board and the backlight did not turn on.
The photos in the SM is pretty much the same as the TV...

[nomoresonys]

Re: old Bravia double fail?

check the fuse on the inverter board.

[eccerr0r]

Re: old Bravia double fail?

Fuse is good, or at least Vdrop across it is 0V.
Agree this is suspicious that both the inverter board or CCFL tubes and the MB are both bad?
This sort of leads back to PSU problems, but standby is working (else the remote wouldn't powerup) and the PSU is giving solid 12V and 24V...

[nomoresonys]

Re: old Bravia double fail?

what kind of meter do you have, close to 0 ohms is short, no continuity is short.

[nomoresonys]

Re: old Bravia double fail?

go ahead and ohm test those mini transformers on the inverter board, they should all be very close to each other, similar testing there: https://www.youtube.com/watch?v=b36w2GNrH6Y

[eccerr0r]

Re: old Bravia double fail?

I'm getting 24V across the input of the board and 0V across the fuse (24V on both sides of the fuse) so there's no short here.

I'm wondering if I should cut bait at this point with both the inverter/CCFL not lighting *and* the mainboard not lighting the optical SPDIF port/not picking up firmware from USB? Unless there's still a chance there's only one thing that's causing both problems other than the PSU as it seems like it's working... Perhaps there's some magic sequence that needs to go through the enable to light the CCFL tubes, but the wire/pin is simply labeled "Enable" (and the other wires on the connector are ground, inverter board failure, and pwm dimmer - a total of 4 wires that go from the mainboard to the inverter board.)

Is it worth to fix the inverter board and then have to also fix the mainboard? I was hoping the mainboard at least show signs of life, I could jury rig a backlight. Or perhaps just fix the inverter board to fleabay the board as "working" as I definitely can't sell the mainboard. About the only thing that I could resale is the PSU, but ... I want another working TV.

[nomoresonys]

Re: old Bravia double fail?

did you test those mini transformers? easy test, I think the thing to do is test the powerboard as stand alone, usually involves using a couple, few, resistors as jumpers and see if the backlights come up and stay on, like UNHOOK the cable from powerboard to mainboard at mainboard and stick the resistor legs in that end of cable if they will fit.

[nomoresonys]

Re: old Bravia double fail?

maybe some of the supertechs can chime in with easier methods, all I can do is try my best, it IS an interesting puzzle for sure.

[nomoresonys]

Re: old Bravia double fail?

what kind of meter do you have, close to 0 ohms is short, no continuity is short.

LOL, This is wrong, my bad.

[eccerr0r]

Re: old Bravia double fail?

O-K! not sure how I screwed up before, as I thought I did the same experiment to segregate the two.

BACKLIGHT WORKS!!! I was able to light it by poking the enable pin. And of course what I see on the screen is disheartening, indicating problem is indeed in the mainboard (or one does have to suspect tcon but right now I think it's the former): a whole bunch random colored vertical lines across the whole display.

Now whether to go buy a mainboard or not... or perhaps it yet can be restored...

[nomoresonys]

Re: old Bravia double fail?

ok, try having one ribbon cable at a time hooked up from tcon to panel, see if theres any display or white screen whatever it shows, do both sides, best to make all unhook and hookups with tv unplugged from power to avoid any errant surges etc.

[eccerr0r]

Re: old Bravia double fail?

Not sure what you mean by tcon to panel connection, thought that was usually soldered?

Anyway with the LVDS cable disconnected - screen is fairly uniformly gray instead of the randomly colored vertical lines uniformly across the screen (no underlying corrupted image visible like "Bravia" that I thought it would normally display upon boot, just lines.)

Still have to focus on the mainboard as it is not supplying the proper enable signal to the backlight - once again is it a double fail of a mainboard and tcon at the same time?

[nomoresonys]

Re: old Bravia double fail?

its the flat ribbon cables that go from tcon to panel driver boards, usually a little flat clip that you snap up with a fingernail, then power up tv with only one side connected, then do the other side, make sure the cable ends are not touching anything like the metal chassis to avoid shorting anything out, they flip up easy, should never force anything.

[nomoresonys]

Re: old Bravia double fail?

can poke around the mainboard and tcon, see if you have any voltages, should probably find at least one spot with 12 volts near where the lvds connector of mainboard and the lvds connector of tcon are, so tcon fuse is ok? see if you have around 12 volts on each side of fuse, metal chassis for ground, can also look mainboard over, sometimes theres many little fuses on them, one or more could be bad if they are there.

[eccerr0r]

Re: old Bravia double fail?

I can see the +5V around the board, and some other voltages but did not xref with SM yet... so unfortunately no obvious problems.

Incidentally it's funny the inverter board is made by Samsung and has some crappy solder job on it. But if it works, it works...

[nomoresonys]

Re: old Bravia double fail?

did you see if you have around 12 volts on each side of fuse on tcon board?

[eccerr0r]

Re: old Bravia double fail?

Can it be assumed the tcon fuse is intact because the behavior of the panel is different of LVDS cable (which has power on it?) is plugged in or not?