Sony Bravia blinking red 7 times after lightening KDL-55DL-55EX720

[thesteve]

Hi. This is my second post. So far no signs of life on this message board.

I have a Sony KDL-55EX720 that works beautifully. But after an incident involving lightening, the set will shut down after a minute or so and flash red 7 times.

I have a donor main board to use to swap parts if necessary. I tried swapping the board completely, but so far have had limited success updating the firmware which turns out is mandatory.

Before I try any risky surface mount soldering, I thought I'd ask for advice.

Thanks.

Steve

[neilc6]

Re: Sony Bravia blinking red 7 times after lightening KDL-55DL-55EX720

You can find a service manual at Elektrotanya if you google. 5 blinks is panel/tcon. I would check for 12V on the tcon fuse. If not present, there may be a blown surface mount fuse on the main board which supplies the 12V. If you have 12V, then try powering up the TV with only one side connected at a time between the tcon and panel and see if one side displays an image/doesn't produce an error.

[thesteve]

Re: Sony Bravia blinking red 7 times after lightening KDL-55DL-55EX720

Thanks for your reply. I was thinking I was blacklisted or something.
This is an artificial problem, I believe brought on by high static voltage near the HDMI section from the HDMI ground.
The 7 blinks seems to be caused by the over temperature detection circuit. Maybe there's an easy way to disable this false logic signal? I have the full schematic which points to a 6 pin surface mount chip, "mm3285fnre." IC9008.

[neilc6]

Re: Sony Bravia blinking red 7 times after lightening KDL-55DL-55EX720

Oops I looked at 5 blinks and not 7 blinks. There is a troubleshooting flowchart in the service manual.

[thesteve]

Re: Sony Bravia blinking red 7 times after lightning KDL-55EX720

Hi, yes, I should have mentioned it's for the thermal sensor. I think the tiny surface mount chip got fried by the lightning. I found the location on the board and the data sheet. Luckily it's located on the top side of the board so I can probe it for logic while it's on. Maybe I can just jumper it to stay happy (if the IC is the problem). Or I could swap it from my other BAT main board.

[thesteve]

Re: Sony Bravia blinking red 7 times after lightening KDL-55DL-55EX720

I found the problem.

The thermal sensor is doing its job... the trouble is its neighbor, the HDMI port processor (ic5500) which gets so hot I burned my finger.
This makes sense since the lightning that zapped my electronics came from the HDMI cable from my cable box.
I remember now, that after restarting the TV after the lightning, the original HDMI port I was using no longer worked.
Then the shut down problem began with the 7 red LEDs.

Oh well, maybe I can put a mongo heat sink on the bad chip and hope only the shorted part burns itself out.

Or maybe I can somehow isolate the pin(s) that are tied to the bad HDMI port.