Sony Bravia KDL-40D3660 - Rebooting every 30 secs

[aziztcf]

Hi!

Just got this "broken" set with interesting problem. The screen takes about 30 seconds before it wakes up(backlight+picture ok), then works for another 30 sec or so before shutting down again. The green light stays on the entire time, then it repeats the process a few times before giving the red 10-blink error indicating "Digital FE Error" according to the service manual.

Voltage on CN6600(Main power to inverter) is steady 390 the entire time, but drops on the inverter side when the backlight and picture go black. There's an INV_ERR pin which at least according to WAX3 training manual should be low, but it reports about 3.4 volts when the screen is on. It too drops to zero when the screen goes off.

The caps look fine, the regulators seem to be doing their job.. I'm totally at loss here, can anyone gimme a hand?

e: I'll get pics and accurate voltage readings tomorrow when I've got the tools. Gonna check the caps anyway.

e2: Well grabbed some pics with my cell phone and bad lighting and way too big file size(so sorry. very tired atm!) Didn't really know where to focus so the pics are kinda all over. Hope they help!

Pictures be here!

[budm]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

That INV_ERR signal is generated when one or more lamps draw too much current.
Please post good clear pictures of the boards.

[tom66]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

When you say it works; do you mean that the TV is usable for those 30 seconds, or just the backlight is on?

[aziztcf]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

When you say it works; do you mean that the TV is usable for those 30 seconds, or just the backlight is on?

The TV is usable, picture and audio work just fine. The remote seems to respond all the time too, it goes to standby.

I'm wondering why the backlight doesn't fire up when powering on if it's just about the INV_ERR signal? Or does the cpu detect it at boot and delay the next try for half an minute?

[tom66]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

The only way to be sure would be to disconnect INV_ERR, connect it to ground, and see if the TV boots up quicker and/or stays on.

[aziztcf]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

Tried to connect INV_ERR to GND, no go. I'm wondering if it's supposed to be high, cause it is during normal operation, then goes to zero when the screen goes off.

[tom66]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

I'd suggest connecting it high (to +5V), but use a limiting resistor of around 100~470 ohms. Then see if it behaves the same.

[aziztcf]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

Tried it, no help.

I just noticed that the unregulated 5v coming from main board is over 7 volts. Could this indicate a problem on the BE1F-board?

[tom66]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

That doesn't sound right; are the other rails off too?

[aziztcf]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

12V audio, Reg 12V, stby 3.3V when in standby, nothing on audio but I guess that's cause there's no input. Back_light rises to 2.9V when screen is on, dimmer at 0.7V.

[tom66]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

What I meant, is are the other rails significantly different compared to their ratings (+/-5% is typical.)

[aziztcf]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

Those were the ratings and they matched. Sorry for being little unclear. Not my first language

[aziztcf]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

Sorry, the line showing about 7,5V was 6V UNREG, not 5v. Checked the caps in the PSU, all seemed fine so I'm really starting to think it's a problem with the main board.

[woodware]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

Hi,
Had very similar problem with Bravia 40s2530. Then brought to service,as couldnt find the mistake. They reinstalled firmware and now is OK. There was the same 30 second work,than off,than another 30 secs,than red blinking 9 or 10 times. SO, try this. Hope will help.

[aziztcf]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

Ok, so I think one of the lamps seem to be drawing too much current. https://www.badcaps.net/forum/attach...5&d=1356302125 shows the same series of controller that my board has. Any way to bypass this easily to see if the problems is on the balancer or DF1 inverter ps.

[tibimakai]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

http://www.youtube.com/watch?v=oE6K4xBVweA

[aziztcf]

Re: Sony Bravia KDL-40D3660 - Rebooting every 30 secs

Hmh, the voltages on balancer transformers seem fine. I measured the FETs on the DF1 board, one of them is ~20V when the set turns on but jumps to ~200V when the inverter shuts down. Losing my mind with this one..