Sony XBR-75X940E intermittent 6 blinks error code

[GoodCapDude]

Hi everyone. First post on Badcaps!

I am trying to fix a Sony 940E from 2017 that either starts normally (and works perfectly until turned off) or goes straight to the 6 blinks error code without showing anything on the screen. It is frustrating to know that it can still work perfectly but is barely usable because of the difficulty starting it up. I am willing to try to short the BL_ERR but I would like to avoid that if possible. Does anyone have a view on this? Thanks a lot.

[EazyBone]

Bl error. It can be that power board above the main one which went bad, it could be led driver, could be bad LEDs. Shorting the pin would probably tell if it's the LEDs are bad if it'll start and you can go to YouTube and do a screen test and see if one of the LEDs is bad.

If LEDs is bad then shorting the pin is the only way beside changing them as far as I know

[Diah]

you have crack soldering point at PSU

[nomoresonys]

Check the soldering as suggested, could be a backlight, suppose it could also possibly be a marginal/bad electrolytic capacitor on one of those boards. The hairdryer trick (just heating the electrolytic caps for a minute or two and trying the tv before they cool off) sometimes works to sniff out a marginal/bad capacitor.

[GoodCapDude]

you have crack soldering point at PSU

Thank you for your reply Diah. I'm not very skilled, I removed one of the three boards forming the PSU (G6, the other two are G75 and G78), I looked at soldiering points but there is little I can identify by just looking, right? Or is a "cracked soldering point" visible to the untrained eye? It's frustrating to think that this set could be back to life with just some solder at the the right spot!

[GoodCapDude]

Bl error. It can be that power board above the main one which went bad, it could be led driver, could be bad LEDs. Shorting the pin would probably tell if it's the LEDs are bad if it'll start and you can go to YouTube and do a screen test and see if one of the LEDs is bad.

If LEDs is bad then shorting the pin is the only way beside changing them as far as I know

Thank you for your reply EazyBone. The leds seem fine when the TV start normally. The problem is that now that it is facing down, I have no access to what's on the screen. I'd rather not move it as it weighs a ton. I can still see the white led at startup, the red led blinking 6 times or whether the panel is normally lit.

[GoodCapDude]

Check the soldering as suggested, could be a backlight, suppose it could also possibly be a marginal/bad electrolytic capacitor on one of those boards. The hairdryer trick (just heating the electrolytic caps for a minute or two and trying the tv before they cool off) sometimes works to sniff out a marginal/bad capacitor.

Thank you for your reply nomoresonys. Your name is thought provoking! 😂 I'm not sure about the hairdryer because those capacitors are so close to each other that I'm not sure I can heat one in particular. Also, since the TV does start normally from time to time, it'll be hard to tell if it's whether I heated up the capacitor. Maybe I should buy a multimeter to test every capacitor? I've seen some device allow testing components without removing them from the board. I really like this TV but maybe the most efficient way to go is trying to short the BL_ERR and just see how much life it still has in it?

[nomoresonys]

Thank you for your reply nomoresonys. Your name is thought provoking! 😂 I'm not sure about the hairdryer because those capacitors are so close to each other that I'm not sure I can heat one in particular. Also, since the TV does start normally from time to time, it'll be hard to tell if it's whether I heated up the capacitor. Maybe I should buy a multimeter to test every capacitor? I've seen some device allow testing components without removing them from the board. I really like this TV but maybe the most efficient way to go is trying to short the BL_ERR and just see how much life it still has in it?

Sure you can try it, if you look closely at how the wire is in the connector you can remove it without having to cut or damage the wire then ground it. That way you can just slip it back on if it's not the problem. At least a lot of them are configured in that manner, I use a really small screwdriver to unlatch it.

[nomoresonys]

Bad solder joints can be easy to spot or tricky, I would add a little to any that look even a little suspect, just be careful not to bridge anything that shouldn't be. Also don't want to get any globs that could result in a bad joint. Pay attention to transformer joints and anything on a heatsink. They work hard and usually crack first. Examples of bad joints there: https://www.google.com/search?client...&bih=671&dpr=1

[GoodCapDude]

Bad solder joints can be easy to spot or tricky, I would add a little to any that look even a little suspect, just be careful not to bridge anything that shouldn't be. Also don't want to get any globs that could result in a bad joint. Pay attention to transformer joints and anything on a heatsink. They work hard and usually crack first. Examples of bad joints there: https://www.google.com/search?client...&bih=671&dpr=1

Thanks for the link. I think I have a clearer view of what a bad joint is. I have checked all 3 boards and did not find anything that really stood out. My confidence level in my assessment is quite low obviously. Also I think it has to be subtle since it works from time to time, right? So I put everything back together and the TV started. But then I turned it off and on and I had the 6 red blinks again. So I'm back to square one.

Thankfully, I can keep the TV opened a few more days but it looks like I'm going eventually to have to ground BL_ERR and throw it away if it does not work. And maybe put it on the wall if it works. But then I may realize that by bypassing the error code, I find a significant backlight problem. There is no way I can investigate the led strips with this beast, it is too massive. I could never put it back together.
Thanks for your help in any case!

[tiki66]

Maybe a segment of LED's won't turn on when they are cold so tv goes into backlight error. But usually when there is something with these tv's and backlight it goes into 4x error, not 6x...

Anyway, try grounding BL_ERR and it could solve your problems. It is pin #27 on CN1001 on LD board that you have to ground (that small flat cable that goes from MB to LD board)

[nomoresonys]

Sonys are notorious for this kind of fault, that is starts sometimes but mostly will get the 6 blink code. Doesn't have to be but I think mostly it's related to a faulty backlight led that works only when it feels like it.

[nomoresonys]

Guess it could be a connection problem, maybe give that single cable going from powerboard to ld/backlight board a little wiggle just to try to make sure none of the wires are broken or only getting intermittent contact and take that cable off and check for burn or discoloration on each end. I use stripped bread ties inserted in the ends of the cable to check each wire for continuity with multimeter.

[GoodCapDude]

Thank you nomoresonys and everybody. I may have found a "cold solder" in at least one these four identical components (first pic). The culprit would be in the close-up pic. Could this explain an erratic start behavior of the TV?

[nomoresonys]

Sure go ahead and add some solder so it looks like the rest and try it.

[nomoresonys]

Any update?

[Davi.p]

Hello, I have repaired 13 of them.... noo it's a joke.. what a beast!! One power board only for PFC, a second board with PFC.. ok i would need the real code of the power board of the last photos and the led driver board so i can find a decent picture, in the shape of 1-xxx-xxx-x ok?.. I'm suspecting the led driver board, especially if it has one bga chip, it may needs a reflow or better.. i do not think bad leds.. useful information could be found in the service uart port log, this is defenitely not a beast for the home tinkerers and jugglers, needs special care, what is the situation there as professional repair shops? bye

[GoodCapDude]

Any update?

Hi nomoresonys, thank you for the interest. I was planning to give an update once the story is over but it's still going on!

So I went to a professional repair shop which is going to test the three boards (forming the power supply) one capacitor and other relevant items at a time (he told me he would desolder them and resolder them). Before that, I tried to ground the BL_ERR and the TV started to blink red four times instead of six times. I was not too sure what to make of that. I hope I did not damage the connector.

I will give an update this week with the outcome. They must get back to me this week.

[GoodCapDude]

Hello, I have repaired 13 of them.... noo it's a joke.. what a beast!! One power board only for PFC, a second board with PFC.. ok i would need the real code of the power board of the last photos and the led driver board so i can find a decent picture, in the shape of 1-xxx-xxx-x ok?.. I'm suspecting the led driver board, especially if it has one bga chip, it may needs a reflow or better.. i do not think bad leds.. useful information could be found in the service uart port log, this is defenitely not a beast for the home tinkerers and jugglers, needs special care, what is the situation there as professional repair shops? bye

I first thought you truly had repaired 13 of them! I don't know what a PFC is. I'm going to post pics of the boards that I sent to a repair shop. I think the led driver board is outside the scope of what I'm willing to try to repair this TV. It's gonna be power supply or nothing. Thanks for your help.

[Davi.p]

why don't to try search for a led driver board by second hand? Which is its code? Is it so uncheap?