40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

[tom66]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

According to my calculations it should give 25.6V and 12.6V... which is still pretty high.

I put it into a little two-transistor power supply. At least the values are close enough so they're probably accurate, my power supply design is different any may regulate differently.

(W scale = volts for 12V)

This should be the correct category:
http://www.digikey.com/scripts/dksea...ity=0&PV174=23

Just select the right resistance value.

[tieny]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

Yep its connected to the 12V output.

[tom66]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

It's probably the 12V output plane. See if it has continuity to the positive terminal of the 12V caps, or output.

[tieny]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

I have the 12.9V here, but i thought it was connected to ground?

Is that huge tracing on the pcb ground? Measuring that i also get 12.9V

[tom66]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

But no 12V coming into feedback? I expect both rails to be involved in the feedback.

[tieny]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

oops, made a mistake there, the 12.9V i wrote should say 26V to output.

[tom66]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

Makes a lot more sense - does 24V come into the feedback at all?

[tieny]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

Hopefully i drew this right, I might of missed a thing or two.

[tom66]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

That seems a bit more realistic; does one of the leads of the TL431 go to the middle of that divider?

[tieny]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

Hmm not sure if its right, but looking at it, it seems to be in parallel with the three main resistors.

[tom66]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

We need to draw out a schematic of this section, can you do that, or do you need help?

[tieny]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

Theres also a 103 resistor (10000 ohms) near the two parallel 923 ohm for the 24V feedback, would it affect it in any way?

[tom66]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

I still don't know if I believe those values - 963 ohm parallel is very low for 24V feedback.

[tieny]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

Ok, so all five resistors?

https://www.badcaps.net/forum/attach...5&d=1359830813
https://www.badcaps.net/forum/attach...6&d=1359831625

thats 102, 123, 752, 183, 564

1000 ohms, 12000 ohms, 7500 ohms, 18000 ohms, and 560000 ohms

Just wondering, since its outputing the wrong voltages, is there any way to force and drop the voltage down by only 1 volt just to get it working?

[tom66]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

Yes, if it is just a number, that is a power of ten, otherwise, you need to use the table.
I suggest you replace all of them to eliminate any doubt.

[tieny]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

Yeah, these two:
https://www.badcaps.net/forum/attach...6&d=1359831625

theres 3 numbers on the resistors, I just thought the 3rd number on it says how many zeros correct?

[tom66]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

Only those resistor values used?

[tieny]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

Precision thin film resistors, "102" or 1000 ohms and "123" or 12000 ohms. thanks

[tom66]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

Get me the values of them, using the previously linked chart, and then I can find the appropriate part or category for each.

[tieny]

Re: 40" Sony LCD KDL-40EX500 Seconds to black (6 blinks)

oops sorry i meant "digikey" lol