sony kdl-46xbr6 slow refresh

[tom66]

Re: sony kdl-46xbr6 slow refresh

This device is fairly simple. You can check if it is in regulation by probing the FB1/FB2 pins (6&11) - these should measure almost exactly 0.8V each.

[freakaftr8]

Re: sony kdl-46xbr6 slow refresh

Agree. I'm almost certain it's the switching controller ic. Just for good measure I ordered replacements.

[freakaftr8]

Re: sony kdl-46xbr6 slow refresh

Crap. The one somewhat working tcon crapped out. Blank screen. Was getting ready to test voltages. All fuses still good

[freakaftr8]

Re: sony kdl-46xbr6 slow refresh

Got the tcon back working. It managed to blow a link resistor between pin 2 and 3 off the IC. This makes be back up my assumption that the IC is bad. Your thoughts? Altgough pun 1 and 2 are fet output pins and the link blew between the IC pin 1 and 2. Hmmm see pic

http://i845.photobucket.com/albums/a...psd5wl5rea.png

[freakaftr8]

Re: sony kdl-46xbr6 slow refresh

Btw. The tcon also took out the fuse on the mainboard. Replaced fuse and that resistor on the tcon and its back working. And I'm getting .8vdc in pin 6 and 11 of the bad board. So it at not be the IC after all

[tom66]

Re: sony kdl-46xbr6 slow refresh

Try measuring pins 7 and 11 too.

[freakaftr8]

Re: sony kdl-46xbr6 slow refresh

well I went ahead and replace that IC No change. so its gotta be something else but I'm not sure what could cause this off and except for incorrect voltages going to the IC possibly?

[tom66]

Re: sony kdl-46xbr6 slow refresh

Are the FETs it drives OK?
Output caps OK, not shorted?
Check volts across output capacitor on both.

[freakaftr8]

Re: sony kdl-46xbr6 slow refresh

The fets are the 8 pin regulators located to the right of the IC correct? Pin 2 and 3 go into pin 4 of the fets as a gate driver. The fets as far as I can tell with a diode meter test ok. This doesn't necessarily mean they are good though? Usually I'm looking for a bridged connection.
All capacitors on the board appear to be ok.

[freakaftr8]

Re: sony kdl-46xbr6 slow refresh

It appears the circuit in question drives the 1.0v to the DDR2 ram. The output of the fets goes one to a microprocessor on the other side.

[freakaftr8]

Re: sony kdl-46xbr6 slow refresh

Well got the new regulators in today. No change. So it's not the regulators or the driver ic or any shorted components in the area. I'm stumped. Could it be what they are driving? The bottom voltages and controllers in question go to the ddr2 ram on the tcon and also go to the processor with sony etched on it.

[freakaftr8]

Re: sony kdl-46xbr6 slow refresh

okay update I started probing around the board it sounded is shorted MLCC capacitor off the PLL 1.0 volt rail which is the rail that was in question. Replaced shorted capacitor still have same slow motion picture. What is the PLL 1.0 volt it looks like its controlling the main video processor which is the chip labeled Sony Cxd9935gb.

I would like to note that this circuit out of all four voltages on the board is the only circuit that has a very low ohms reading across all the capacitors. Roughly 43 Ohms. even on the board that produces a good picture but only last for a few minutes until it goes to vertical stripes has 43 Ohms across. does seem a little odd but I can't find any shorted capacitors on either the working or the non-working board. Even when I had the voltage regulators removed from the board I still got 43 Ohms across the pins

[freakaftr8]

Re: sony kdl-46xbr6 slow refresh

Ok should have looked into this closer. essentially there's four voltage outputs. it appears that the first voltage output is 3.3 volt. Second voltage output is 1.9 volts. Third output voltage is 1.8 volts and the last output voltage is 1.0 Volt. this is on v good bored that works for a little bit. On the bed bored both of these middle voltages are 1.8 volt. My question is why would they have two independent rails running the same voltage? Unless something's wrong

[tom66]

Re: sony kdl-46xbr6 slow refresh

PLL 1V is for the CPU, it's the PhaseLockLoop power supply.

The rails might be independent because of noise concerns - or if they power up separately or in sequence.

[freakaftr8]

Re: sony kdl-46xbr6 slow refresh

I'm giving up on these t-con boards it just blew a main board fuse on mainboard. In my opinion not worth the hassle anymore as I believe it is a processor issue no. And in that case BGA no thank you. on the other hand on the other t-con board is the AS15 chip supposed to get super hot within seconds

[bluetinc]

Re: sony kdl-46xbr6 slow refresh

Hey, I figured I'd chime in here as I'm chasing the same problem with the original failure showing as the TV shutting down after a few hours with a 14 Flash pattern, finally not displaying anything with F603 blown.
So far, like you guys, I've tracked this to the 1.0V Core power for the Sony Cayenni-T. I've taken the power switcher out of the circuit and powered the 1.0V externally and everything looks perfect. That isolates this into the switching supply. I'll keep you guys updated.

[freakaftr8]

Re: sony kdl-46xbr6 slow refresh

Hey, I figured I'd chime in here as I'm chasing the same problem with the original failure showing as the TV shutting down after a few hours with a 14 Flash pattern, finally not displaying anything with F603 blown.
So far, like you guys, I've tracked this to the 1.0V Core power for the Sony Cayenni-T. I've taken the power switcher out of the circuit and powered the 1.0V externally and everything looks perfect. That isolates this into the switching supply. I'll keep you guys updated.

did you have the usual slow image problem after replacing f603? 2 tcons I have presented this after replacing the fuse.
The other has perfect image for 5 mins then fades out.
Can you elaborate on what switcher you removed and where you injected the 1.0 volt.to and where did you get the voltage from? Think we may be on to something. I've already replaced the 4 diodes and the fuse and the two 9853a ics and the rss040p03 and the rss040n03 power ics to no avail. So that almost sums up the switching circuits.

[lookimback]

Re: sony kdl-46xbr6 slow refresh

AS15s have always had a high failure rate, could be a problem there. I don't know if they usually get real hot like that. I've only ever seen the bleached out, and negative picture with them though. Other than that, maybe a processor issue. Could explain why they're rare and expensive.

[freakaftr8]

Re: sony kdl-46xbr6 slow refresh

This particular board does not use an AS15.

[lookimback]

Re: sony kdl-46xbr6 slow refresh

Oh, I misread your earlier comment about the AS15.