Sony Bravia no Picture

[Th3_uN1Qu3]

Re: Sony Bravia no Picture

Yeah, could've been a bad fuse, or maybe someone misread the label and dropped a 0.5A instead of a 5A. I always thought SMD fuses were a bad idea.

[tlm387]

Re: Sony Bravia no Picture

Actually the old t-con board turned out to be fine I'm am running the original. My best guess was a bad fuse from the manufacturer, or a perhaps a power surge at some point in time.

[Th3_uN1Qu3]

Re: Sony Bravia no Picture

0.7A is way, way below the 5A rating. Which means you should be comfortable running this TV as it is now. Most likely, at some point, something went awry (most likely the old t-con board, as i recall you have bought a replacement) and the fuse blew.

[tlm387]

Re: Sony Bravia no Picture

So what. Solder wires to the fuse terminals, bring them out, hook your amp meter up. Done.

Great Idea!

I am measuring ~.653 DC Amps with the LCD on and a movie playing, and the meter wired in circuit. Now thats less than the 5 AMP rating so all should be well right? Does that sound like a normal reading?

To me that does not sound like enough AMPS to power the entire t-con and LCD panel, but don't really have a working knowledge of electricity so I could be wrong here.

And I assume I measure this on DC current and not AC. Is this correct?

Thanks again for all your input!

[Th3_uN1Qu3]

Re: Sony Bravia no Picture

Yeah I want to test the current load at that point, but it is on the underside of the main board and will be very difficult to measure with everything plugged in.

So what. Solder wires to the fuse terminals, bring them out, hook your amp meter up. Done.

[tlm387]

Re: Sony Bravia no Picture

Yeah I want to test the current load at that point, but it is on the underside of the main board and will be very difficult to measure with everything plugged in.

I only bridged the fuse so that I could see if that fuse was the issue. I have only tested the tv once and I am not leaving it plugged in unattended. So until the new main board comes in I will not be enjoying this tv.

[PlainBill]

Re: Sony Bravia no Picture

Well I could be wrong here, but the t-con has a 3A fuse (not sure of it's voltage), which is less than the 5A fuse on the main board. So if the panel or t-con itself was drawing too much current than theoretically should't the 3A fuse blow first?

Maybe. Or maybe the tcon has multiple fuses off the power input. It's a much larger scale, but at one time fuses in a home fusebox all had identical bases. If a 15 amp fuse blew, put in a 20 amp or 30 amp. Heck, put in a penny!!! Guess how many fires started that way?

Now, you are a grown-up, it's your TV, you can do what you want with it. Myself, I would remove the solder, put an ammeter across the blown fuse and see how much current is drawn. If it's well below 5 amps I'd replace the fuse. If it's close to or more than 5 amps, I'd find out where the current is going.

PlainBill

[PlainBill]

Re: Sony Bravia no Picture

Somewhere around I have exhibit 'B' for this issue. Exhibit 'A' is no longer in my possession.

Long version. Years ago I swapped for a crappy Compaq notebook - probably a '486 based system. (Yeah, that long ago). One of the problems was a circular dead spot the size of a dime in the lower right corner of the display. After buying a parts system and some more swapping I wound up with one pretty good system and one that worked but had a bad display. Both went on to other users. So much for exhibit 'A'.

About two years ago I advertised on the local Freecycle "Looking for non-working monitors." One of the items I picked up was a 15" Acer monitor that used an external power supply. As soon as I saw it I knew that was going to be a parts monitor - it looked like the top of the case had melted, and there was a dark spot about the size of a match head toward the upper right corner of the screen. The explanation offered for the melted case was that the monitor wouldn't come on unless it was warm in the room, so the owner had used a hair dryer to heat it up!!! Testing the monitor showed 'no backlight'. I opened it up, used a 'case mod inverter' to power the backlights and turned it on. Yes, it's working, but this dark spot is now a bright spot. OOOHH!! Burned out transistors!! I turn off the power to the inverter and I see the spot is still glowing. SOMETHING is getting hot in there!!!.

Now, could shorting transistors (or drivers) in an LCD panel start a fire? I don't know, but I sure wouldn't want to find out.

PlainBill

[cadillacman]

Re: Sony Bravia no Picture

That made my day.

@ OP: be sure to remove the jumper and drop in a new 5A fuse when the new board arrives - you don't want to melt anything. I've done that enough times.

thats why you use a tiny strand of wire

was that out loud?

yeah man it had to blow for a reason. If after fuse replacement it stays working, what the hell man go with it. Im sure you probhably already have the damn thing back togther, but take it back apart and put that fuse in there. Id hate to hear from you a month from now saying " damn sony burned my house down!"

Usually after i fix tvs i make them my personal tv for a week. if all is good they they go back to thier owner or up for sale depending. ( and sometimes i just cant help but keep them for myself)

im definately going to remember this post the next time i have to deal with a headache kdl series sony. As if the kraptastic lcd panel isnt enough on these pieces of poo

[tlm387]

Re: Sony Bravia no Picture

Well, the answer won't give you a lot of comfort. That circuit is the switch supplying power to the panel. Nothing on this section of the schematic could cause the fuse to blow, even if it shorted out. The conclusions are a tcon or panel drawing too much current, or a defective fuse. If you notice the shaded triangle with the ! next to the fuse, that fuse is a safety item.

PlainBill

Well I could be wrong here, but the t-con has a 3A fuse (not sure of it's voltage), which is less than the 5A fuse on the main board. So if the panel or t-con itself was drawing too much current than theoretically should't the 3A fuse blow first?

[Th3_uN1Qu3]

Re: Sony Bravia no Picture

or a defective fuse.

That made my day.

@ OP: be sure to remove the jumper and drop in a new 5A fuse when the new board arrives - you don't want to melt anything. I've done that enough times.

[PlainBill]

Re: Sony Bravia no Picture

I GOT THE SUCKER WORKING!!!!

Apparently I did I bad job on my jumper solder job, when i did it I just did a visual inspection to see that I had bridged blown fuse, being the size of a small bread crumb I should have tested for continuity. (Among other potential problems)

So going back over the schematics I re tested all the fuses on the main (input) board. There are a 6 fuses listed on the schematics. There is a fuse called F1422 (5A 24V) which powers the TPC8109(TE12L) chip. This chip then runs out to the display. At least that is what I am interpreting from the attached schematic. After my jumper job I still was not getting continuity from this fuse, so I redid the solder connection and tested again for continuity and the test was positive. I made sure I did the best solder job I could with a my $9 dollar radio shack soldering iron and no magnifying glass. This time I removed the F1422 and just soldered the two points on the board together.

I plugged it all back in and it worked. I'm shocked that a $.95 cent fuse which is smaller than...most things I've ever seen, knocked out this whole tv. Seeing as how that fuse blew for a reason, I'm still going to run the replacement board once it arrives. But I'm glad to know why this tv stopped working.

Now if I could just figure out what blew that fuse...

Anyways I owe it to you all for helping me brainstorm through this process. MUCH THANKS!

Well, the answer won't give you a lot of comfort. That circuit is the switch supplying power to the panel. Nothing on this section of the schematic could cause the fuse to blow, even if it shorted out. The conclusions are a tcon or panel drawing too much current, or a defective fuse. If you notice the shaded triangle with the ! next to the fuse, that fuse is a safety item.

PlainBill

[tlm387]

Re: Sony Bravia no Picture

I GOT THE SUCKER WORKING!!!!

Apparently I did I bad job on my jumper solder job, when i did it I just did a visual inspection to see that I had bridged blown fuse, being the size of a small bread crumb I should have tested for continuity. (Among other potential problems)

So going back over the schematics I re tested all the fuses on the main (input) board. There are a 6 fuses listed on the schematics. There is a fuse called F1422 (5A 24V) which powers the TPC8109(TE12L) chip. This chip then runs out to the display. At least that is what I am interpreting from the attached schematic. After my jumper job I still was not getting continuity from this fuse, so I redid the solder connection and tested again for continuity and the test was positive. I made sure I did the best solder job I could with a my $9 dollar radio shack soldering iron and no magnifying glass. This time I removed the F1422 and just soldered the two points on the board together.

I plugged it all back in and it worked. I'm shocked that a $.95 cent fuse which is smaller than...most things I've ever seen, knocked out this whole tv. Seeing as how that fuse blew for a reason, I'm still going to run the replacement board once it arrives. But I'm glad to know why this tv stopped working.

Now if I could just figure out what blew that fuse...

Anyways I owe it to you all for helping me brainstorm through this process. MUCH THANKS!

[tlm387]

Re: Sony Bravia no Picture

I work on these stupid sonys all the time.

there is a VERY EXTREMELY SUPER MINI TINY fuse on the signal board that popped when the t-con went bad. I am thinking smaller than SMD0603
you must replace this fuse. This fuse supplies the 12V to the T-con board, and if popped, you will get no 12V to the panel.

These boards are riddled with tiny fuses. id say theres maybe 5 to 10 of them in various circuits. there is one popped, and i think its near the center of the board on the back side.

Yeah I spent some time testing the fuses that I could find. I found a 5A 24V micro fuse type 1608 (Sony part #1-576-933-21) that I just could not get continuity from so I thought I found the problem. I jumped the fuse with a dab of solder, but all that happened was a rely clicking on and off until the standby light flashed a main board error.

So i un-soldered the jumper and the tv went back to behaving as it did in my first post.

For the record I have checked the fuse on the t-con and its appears to be fine.

Rather than run the risk of damaging the tv further by jumping fuses that have blown for a reason, I went ahead and ordered a replacement main board from MAT Electronics. I'll post my results when it arrives. Any body have experience with this company? I'm a little concerned because I never received a conformation email.

[Scenic]

Re: Sony Bravia no Picture

I should have been a doctor. They get to work on the same model day after day.

[cadiman]

Re: Sony Bravia no Picture

That would be why tvs don`t work after replacing the t-con board?

This happens to me every time I think I learned a bit more than the day before... then a different model tv kicks my butt and I start all over again.

I should have been a doctor. They get to work on the same model day after day.

[mbates14]

Re: Sony Bravia no Picture

I work on these stupid sonys all the time.

there is a VERY EXTREMELY SUPER MINI TINY fuse on the signal board that popped when the t-con went bad. I am thinking smaller than SMD0603
you must replace this fuse. This fuse supplies the 12V to the T-con board, and if popped, you will get no 12V to the panel.

These boards are riddled with tiny fuses. id say theres maybe 5 to 10 of them in various circuits. there is one popped, and i think its near the center of the board on the back side.

[cadiman]

Re: Sony Bravia no Picture

I have 12v on a kdl 32xbr4. A grey panel is a blown fuse on t-con board.
I would not trust a used t_con. They all seem to be bad or going bad with Sony.

What I am having trouble with is some of these sonys are repaired with a new t-con board (not a used one) and some are not repaired by replacing the t-con board.
I don`t see how a whole panel can fail and I think people are buying bad t-con boards from ebay that people think have a faulty panel.

I am pretty sure it is a t-con failure. The problem is a new one is very expensive.

I have read more info on faulty t-con boards than bad panels on Sony.

I wish I had a working sony xbr to test this theory.

[PlainBill]

Re: Sony Bravia no Picture

Just to be certain, does anybody know how much voltage I should expect to see going into the t-con?

I would expect to see either 5V or 12V going into the tcon. 0.16 Volts is much too low. I would trace the supply line back to the main board.

PlainBill

[tlm387]

Re: Sony Bravia no Picture

Just to be certain, does anybody know how much voltage I should expect to see going into the t-con?