Sony XBR75X850C no picture backlights on

[jetadm123]

Re: Sony XBR75X850C no picture backlights on

Congrats on the fix! Love to see a photo of that 75" Sony up and running!

[freakaftr8]

Re: Sony XBR75X850C no picture backlights on

Thanks. I manage to find 90% of all the screws to go back into the assembly. I really tore this one down. Interesting that through the tcon it must talk to the right panel board that has the panel driver eeprom IC. The left does not have this IC. So if there is a breach On the right panel board you cannot cross talk and send information the left. Essentially is a W output.. in order of format, Input conformation to output back to input then input to other side. If tcon does not get confirmation on the right side which houses the Panel ID IC, it will not send anything to the left nor allow tcon voltages to come up on tcon. This is why I saw a picture when voltage was forced, Ignoring the confirmation.

Pics to come.

[jeffer76]

Re: Sony XBR75X850C no picture backlights on

Can you please post photos of the parts replaced, locations, and part numbers of the replacements parts used.
I'm sure this will help many other people.

[freakaftr8]

Re: Sony XBR75X850C no picture backlights on

I found a shorted M LCC capacitor at location CSA191 on left panel source driver board.

I did not get the picture of the shorted MLCC capacitor. I took the picture but somehow it got deleted off my camera and now I have the TV all back together unfortunately.. But in the end this was the only problem with the TV why it had no picture. Also it appears that the tcon originally was bad

[freakaftr8]

Re: Sony XBR75X850C no picture backlights on

Also it appears it's a 25v 1uf MLCC

[dooby91]

Re: Sony XBR75X850C no picture backlights on

I've been working on a similar tv the XBR55X930D. At first I though just like you did replace the T-Con and I would be good to go. I have the tv broke down right now and need some advice. The symptoms are very similar like the T-Con is not turning on. My experience in component level repair is very limited. TV has no picture, has backlight and menu sounds when clicking the remote. I tested AVDD and I get nothing on my meter. I jumped twelve volts to the panel to AVDD and saw the screen change. I'm not sure what im looking for to tell if the panel or buffer boards are bad.

[budm]

Re: Sony XBR75X850C no picture backlights on

I've been working on a similar tv the XBR55X930D. At first I though just like you did replace the T-Con and I would be good to go. I have the tv broke down right now and need some advice. The symptoms are very similar like the T-Con is not turning on. My experience in component level repair is very limited. TV has no picture, has backlight and menu sounds when clicking the remote. I tested AVDD and I get nothing on my meter. I jumped twelve volts to the panel to AVDD and saw the screen change. I'm not sure what im looking for to tell if the panel or buffer boards are bad.

Any good clear straight shot pictures of your T-CON board?
Do you have 12VDC at both end of the SMD fuse with ref. to ground on the T-CON board?
The AVDD is the boosted Voltage generated by the LCD BIAS power supplies IC.

[dooby91]

Re: Sony XBR75X850C no picture backlights on

Yes 12v fuse is good on the T-Con Board and getting 12v with the meter. Again my experience is limited but i think the panel or one the the components after the T-Con is bad/shorted. When testing the voltages going out the the T-Con going to the panel I get 1.8 and 0.5 pretty much everywhere. I'll take some pics for you guys tomorrow I'm out of town right now.

Thanks

[budm]

Re: Sony XBR75X850C no picture backlights on

Once we get the pictures then we can see the P/N as printed on top of the LCD BIAS power supply IC and then look up the spec sheet for it.

[budm]

Re: Sony XBR75X850C no picture backlights on

BTW, since your TV model is not the same as OP, you should start a new thread and also upload the pictures of the backside of the TV showing all the boards. OP 's TV has FRC board and the T-CON board and he found bad cap on the panel board (tab bonding board).