Sony KDL-46X3500 switches off and shows 5 red led diagnosis.

[diif]

Re: Sony KDL-46X3500 switches off and shows 5 red led diagnosis.

It's "too fast", not "to fast".

Yep Muphry's Law in action.

[nomoresonys]

Re: Sony KDL-46X3500 switches off and shows 5 red led diagnosis.

It's "too fast", not "to fast".

LOL, good job, you caught the spelling cop in his own trap.

[RJARRRPCGP]

Re: Sony KDL-46X3500 switches off and shows 5 red led diagnosis.

TV is 2008 model LCD and not LED. If OP included pics from back of the tv, it would be more obvious.

So it's a "Core 2 era" TV. I would check the caps.

[Jas123]

Re: Sony KDL-46X3500 switches off and shows 5 red led diagnosis.

Hi guys, sorry for the delay, I have extreme personal problems, but nothing new.

So.

Lots of progress, then lots of tears.

I shorted the connector (left power on) as I connected to main board. TV turned off. Pulled main board and discover fuse close to connector had gone open. NO replacement, so shorted it with solder.

TV turned back on to 5 led fault...so hopefully back to where I was.

---

I could hear a ticking sound coming from behind the cover of what I am now calling the "secondary" TCON board.

I had to partially remove DF2 the primary power board for inverter, to give enough clearance to remove the heat-sink and cover on secondary TCON board.

I noticed the ticking sound would start and then when the backlight eventually came on, it would stop. (It may have been coming from the actual bulbs..)

Anyhow, I also simultaneously discovered that one of the fuses on the "primary" TCON board was partially open. Only letting 2V of 6V supply through.

Again, I brutally remedied this by shorting the fuse with solder.

I then connected everything and turned on the power without re-securing any of the boards properly (live and learn) and promptly somehow blew (bright white light and open..)another fuse in front of my eyes.

Guess what.

I brutally shorted that fuse as well. (No Mercy)

And this time, screwed all the boards back into place before I turned the power on.

Low and behold, a screaming noise from, I believe, the secondary TCON board for about 5 secs and then BOOOOOOOOOOOOOM....

Backlights came on.

Turn TV on and off, repeat, backlight consistantly comes on after short 3-5 second screaming sound. (Ahhhhhhhhhhhh...then on.)

NO picture however.

Shone a torch into the screen but couldn't make out any text.

NO video output on KDL-46X500, because I was going to attach a slave display to see if I got a picture then I know the main board/main AV Board (they're connected) was ok.

And that's where I was.

UNTIL.


As I was merrily testing voltages, comparatively where possible, I changed the lenses in eye wear to more extreme focus. This affected my depth perception and I managed to short (notice the pattern here..) one of the two MOSFET's on the DF3 secondary power invert board.

Proper spark and shut down.

I pulled the board and both the FET transistors had shorted.

I mined two replacements from scrap and fitted them. Not identical - 7A instead of 10A. And resistance (is it RDs?) was 1.25 ohms, where the originals were 0.75 ohms.)

My intention was to put them in and see if I could get the TV to turn on, even if the Inverter didn't like the slightly different voltages..

Once fitted, they read 30V on one (north sitting) and 26V on other (south sitting) on middle legs. 124AC on outer legs.

Comparably, on DF2 the primary inverter board (not directly shorted!!), both FET transistor middle legs read 36V. The outer two legs read 124AC.

The TV didn't turn on.

I might be imagining it, but I took the reading off the MOSFETs before and i remember the being more like 60-70V. But I could easily be mis-remembering.

The four large diodes next to the MOSFETs, directly in circuit, at cathode, read - DF2 37, 124, 37, 124 / DF3 124, 30, 124, 26.

At the anode, all 8 are 124V.

The TV now has standby voltage (5V) only at main power board, but all other DC volts - nothing. It seems the main power board is not getting the signal to turn on maybe?

I have ordered hopefully the correct comparable MOSFETs (FQPF 10N60 N-Channel MOSFET, 10A 600V) to replace original K3569, These have correct RDs? of 0.75 ohm and are 10A.

With AC voltage present at the MOSFETs on DF3 Inverter power board, even if they are not ideal, I was hoping the TV would at least turn on.

I have 3 red led fault - power problem - No turny on.

Until I replace the MOFETs with the ones I have ordered, I will not know if I am back to backlight's and no picture.

To be honest, this has taken a week of my time, and me learning on the hoof.

I have accidentally shorted enough things to wonder about the integrity of the primary TCON and Main board at this point.

I will fit these MOSFETs and I am hoping with your experience I can isolate other components that suffered in the "Big Short", as I now describe it.

Practically speaking, I am able to identify and read the pins on the relevant IC in line with troubleshoot guidelines.

So I think at this stage, I would be interested to fix this power fault. Then do some pin checks to see if main board / main AV board and TCON primary and secondary are functioning as they should be.

Unfortunately I had a day of usage with this TV and I was blown away by the quality in comparison to the cheap 32" $200 set that I own. Particularly as it was free and it was rescued. I have rescued and fixed maybe 20 items in my house from the rubbish, and these small victories go a long way in helping me cope with the personal problems I touched upon before.

I would really like to recover this TV, but it would need to be a guaranteed return as I don't have the money to waste. I am well behind at the moment.

The problem with the UK is the sellers are not reputable.

If I fail with this repair, and to be honest at this stage I give myself maybe 30% chance of success - too many uncertainties. (Which could be eliminated with some measured testing and your help - maybe I have a 40% chance. )

But if I fail, I would consider buying and replacing the boards as a set. I am aware that the TV is set up to use existing boards in the bios, and replacing a board with another, even if correct board, TV may not work..I am a bit grey on this...

I will upload pictures.

On another note. I got a second TV form this guy at the same time. KDL-37U4000. where as the big one worked straight away, contrary to him telling me it wouldn't turn on, the 37" had colour problems.

And it did.

I have started a new thread for that TV. I have isolated the fault (AS15-U SMD IC) , but I have a specific question relating to compatibility in replacing TCON board. https://www.badcaps.net/forum/showth...368#post901368

All the best, hope to hear from you soon.

And for the posters at each other over grammar/diagnosis etc - I feel for you both, but lifes tooooo short. Please be respectful to each other, it's just not worth it. If you can't agree to disagree and shake virtual hands - fresh start -bygones be bygones......then just ignore each other. Same result - no upsetty - lake peaceful.

[nomoresonys]

Re: Sony KDL-46X3500 switches off and shows 5 red led diagnosis.

You may have screwed up a lot of things with the "solder fuses" that's a NO NO, grab some pico fuses they don't cost much and try to follow the techs directions, good luck.

[SLK001]

Re: Sony KDL-46X3500 switches off and shows 5 red led diagnosis.

Dude, I recommend that you take up basket weaving. Playing around with potentially lethal voltages like you are can get you killed.

You should NEVER short a fuse, unless you know what caused it to blow and have FIXED it.

[Jas123]

Re: Sony KDL-46X3500 switches off and shows 5 red led diagnosis.

"Playing around with lethal voltages, like you're doing"

I know how and why the fuses blew, I know shorting them is far from ideal - stuck for options at the time.

The voltages on the control boards are minimal - the only risk is frying the board, rather than risk to self.

I didn't pay for the TV, I don't really give a damn.

If I had made any progress I would have switched them out.

Although the lesson what you are attempting to give is true, the extremely patronising tone, is unwarranted.

You don't know me.

Wind your neck in a bit my friend.

If you can't contribute without patronising, then feel free not to.

No problem.

Have a nice day.