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Old 07-02-2013, 10:01 PM   #1
DaBoys
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Default Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

TV was on and suddenly went dark with no sound and led started blinking twice which according to the service manual, is the G6 power supply board (PFC, 3.3V STBY and 12 volt regulated). It also has a G8 board that is the LLC resonance circuit board and provides the 24V regulated. This board still was providing the 3.3V STBY, of course since I was getting blink codes and also the AC off detect 3.3V.

I ordered a NEW board (not Ebay) and when I installed it, it did nothing. No picture, sound and no voltages except AC to main rectifier and a rectifier output that is low but no DC outputs. Assumed I had gotten a bad board and returned it for a new one and it did exactly the same thing.

When I put the original board back in, it still gave the same indication of 2 blinks and standby power available. I started measuring around and found the R6540 resistor/fuse was blown. It is just before the circuit branches to feed some more circuits that eventually provide some of the 12V regulated outputs and the PFC out that feeds the G8 board. I hope to replace the resistor/fuse and install the G8 board and hopefully this will not just the board again because one of the other boards besides the G8 board is actually causing the problem

I have the schematics but they are in the service manual that I have and the size is 18MB so I'm not sure if this site allows uploads that big.

This G6 board has outputs the aforementioned G8 bard as well as to the BATX (main) board and the T-CON board and I hope these boards aren't the ones with the short.

I am hoping someone is knowledgeable about this setup and has some warnings or checks I can perform. I am not very familiar with switching power supplies and it seems weird to be doing DC measurements on circuitry feeding a transformer but I guess that's the only way you get a reading of that high frequency chopped signal (at least that's what I remember is occurring).

Right now, I have the G6 board isolated and am making the measurements with no connection to adjacent boards.

I have looked at the caps and they don't have visual signs of failure and after looking closer, I did actually see some staining by that resistor/fuse that blew.
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Old 07-02-2013, 10:03 PM   #2
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

Trying to upload service manual to see if I can. Guess I can't.

Last edited by DaBoys; 07-02-2013 at 10:07 PM.. Reason: To upload document
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Old 07-03-2013, 03:18 PM   #3
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

I was hoping to get a response from a tv repair guru but sadly I didn't. I ordered the G8 board and replaced it. Then replaced the R6540 fuse/resistor on the G6 board and called Sony support to see if there were any final checks I can do to make sure the G6 board has normal voltages. They were as worthless as I thought. They just told me to call a serviceman. So I just plugged it in and low and behold, it turned back on. So, the problem was the G8 board failed and took out the G6 fuse/resistor. I hope I can at least help someone on this forum.
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Old 07-03-2013, 03:32 PM   #4
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

One final note regarding Sony. The whole reason I had this TV in the first place was that my original Sony had the problem with the green hue that was an extremely common problem. So much so, that it had a class action lawsuit and so they offered a discounted new TV as a remedy. When I got the TV, I wasn't given the option to buy an extended warranty and wasn't even given a receipt that showed how much I paid for it. I called about that and they said they won't give me one and if I have a problem just use my shipping document. Then when it failed 13 months later (1 month after warranty expired), I called to see if they would repair it since it was only out by 1 month and the reason I had it in the first place was because my previous TV had a major defect. I thought they would want to keep good customer relations. I, of course, was very wrong. I had read in other posts by a SONYCARES badcaps user that they would provide actual TECHNICAL support and I see that was baloney. So, needless to say, I will never buy another Sony product and I have 3 Sony TVs (not including the one that had the first defect), a home theater system, a DVD recorder, a DVD player and a Playstation 3. No wonder they are no longer number 1.
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Old 01-24-2014, 07:09 PM   #5
ari2009
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Default Re: Where you bought that R6540?

I have the same problem on this fuse resistor. Need to replace
Thanks
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Old 03-16-2015, 10:29 AM   #6
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

I have two blinks on KDL-55NX720.

I still need to check R6540 fuse which is providing power to G7 board (LED power board).
On G7 board, i found short on Q6602 and Q6603. Did anyone try to replace just those transistors to make the board work?

Thanks
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Old 03-16-2015, 11:55 AM   #7
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

Also can someone send me where i can order R6540 fuse/resistor. Its 0.1ohm 0.5W fuse resistor.

thanks
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Old 03-16-2015, 01:52 PM   #8
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

I have a working 55EX720, it's the screen that is messed up. If anybody needs something, let me know.
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Old 03-16-2015, 04:19 PM   #9
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

Hi, Champaklal, I was searching youtub and found a video with title "Sony kdl 46ex523 blinks twice 2 times wont turn on fix repair" maybe it can help you. I have the same problem, a Sony KDL-46EX501. It doesn't turn on and standby light blinks twice, turns off and repeats. I need some guidance as to what to test other than the connector's pins on the power board. I hope the video is of some helps to you.
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Old 03-16-2015, 06:15 PM   #10
champaklal
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

thanks for the video link Mandraco. In my tv, i have two board. One - power board and another converter board for LED power supplies.

I order two transistors and fuse so lets see if that fixes the issue.

I could see short on those transistors and fuse(R6540) is open so most likely that might be problem to two blinks.
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Old 03-16-2015, 11:31 PM   #11
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

KDL60EX720_schematic

wbr
Attached Files
File Type: rar KDL60EX720_sch.rar (9.92 MB, 197 views)
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Old 03-17-2015, 09:35 AM   #12
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

What is a best heat sink compound to use so those transistor which i will be replacing will last long.
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Old 03-22-2015, 11:21 AM   #13
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

replaced those two transistors and fuse register. TV is working now.
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Old 09-23-2015, 07:18 AM   #14
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

Can someone email me the technical docs for this set? Im troubleshooting a KDL 55EX720 and it is powering down, then giving me 4 red led blinks. Im guessing this one is similar to the KDL 60EX720
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Old 11-16-2016, 03:48 PM   #15
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

Can you tell me where you ordered the transistors from? Thanks.
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Old 02-13-2017, 05:36 PM   #16
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Default Re: Sony KDL 60EX720 with 2 blinks but not the prblem from service manual

Shop jimmy has aps299 power supply repair kit.
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