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!