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Sony TV that won't turn on, help!

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ben w

New Member
I have a Sony flat panel, model KDL-46BX420. It won't power on or do anything. I can hear the circuits when I plug it in. There are two solid green lights on the bottom left front panel. I think one of them is the sleep timer light? Not sure what the other light is, just has a symbol thats a little vertical line. Any help or ideas on what the problem is would be greatly appreciated. I hope Im posting this in the correct spot :)
 

DerStrom8

Super Moderator
It's very difficult to say without seeing the TV first-hand. Is there any chance you could open it up and take pictures of the boards?

Matt
 

alec_t

Well-Known Member
Most Helpful Member
Do the 2 green lights provide an error code?
 

DerStrom8

Super Moderator
Before you do that, let's take a look at the manual: http://www.searspartsdirect.com/partsdirect/user-manuals/KDL46BX420-sony-parts-LCD+TELEVISION-manual

The LED on the right shows whether power is on or off. According to your description, it is powered on so the statement "It will not power on" is false.

The LED just left of center is the picture off LED. If it is green, it means the power saving is set to PICTURE OFF.

The LED just right of center is the standby LED. It will light up red when the TV is in standby mode.


You said the picture off LED is lit up green, which means there is not a problem at all--your TV is working as expected. You will have to change the power saving mode so that the picture is not switched off.

Sorry for asking you to open it up first, that was the electrical engineer in me :p

Hope this helps,
Matt
 

ben w

New Member
Im sorry if I didn't word it correctly. I meant when I plug it in, the TV does get power. It just doesn't do anything when I hit the power button on both the remote and on the TV. There is no blinking lights indicating any error codes. I never changed any power saving settings. Even if I needed to change the power saving mode, how would I do that if the screen wont come on to access settings?
 

alec_t

Well-Known Member
Most Helpful Member
Even if I needed to change the power saving mode, how would I do that if the screen wont come on to access settings?
I was wondering that. Does your owners's manual indicate how to do a master reset back to factory defaults?
 

DerStrom8

Super Moderator
Even if I needed to change the power saving mode, how would I do that if the screen wont come on to access settings?
I was wondering that as well, but in case you didn't notice I linked you directly to the manual. I did so for a reason.

Matt
 

ben w

New Member
yes I tried the master reset funtion. Nothing happened. Thanks for the link. Whats weird is all the other problems people have been posting involve blinking/red LED lights. After googling for days I haven't came across one person that has the two solid green LEDs. Of course Sony hasn't been any help, they just tell me to take it to get serviced.
 

RCinFLA

Well-Known Member
Look for aluminum electrolytic caps with budging tops. Most common problem where set won't turn on.
Many flat panel TV's and monitor switching power supplies violate the peak ripple current specs on filter caps causing them to run hot and dry out.

Replace with higher voltage rated of same cap value if size allows.
 

ben w

New Member
Look for aluminum electrolytic caps with budging tops. Most common problem where set won't turn on.
Many flat panel TV's and monitor switching power supplies violate the peak ripple current specs on filter caps causing them to run hot and dry out.

Replace with higher voltage rated of same cap value if size allows.
damn. I wish I was more familiar with circuit boards. Im not sure what to look for, but I'm willing to try. I was sure the two solid green lights would be some sort of error code someone would know...Even if I cant figure it out, I appreciate yalls help :)
 
Last edited:

Nigel Goodwin

Super Moderator
Most Helpful Member
Look for aluminum electrolytic caps with budging tops. Most common problem where set won't turn on.
Many flat panel TV's and monitor switching power supplies violate the peak ripple current specs on filter caps causing them to run hot and dry out.

Replace with higher voltage rated of same cap value if size allows.

It's NOT a problem with Sony sets, they use higher quality components (at least in Europe :D), I've never seen a Sony TV with capacitor problems of that kind.

No point in replacing with higher voltage either, it's not the voltage rating that's the problem - it's the cheap crappy electrolytic's that the cheaper manufacturers use, you simply need to replace them with good quality 105 degree (low ESR if you can get them) capacitors, Panasonic and Rubycon tend to be good.
 

MrAl

Well-Known Member
Most Helpful Member
Hi,

Does your TV still have sound? That is when you turn the volume up, can you hear the program show even though you can not see the picture?

That happened to my set and it turned out there were bad electrolytic capacitors. Once they were replaced (about $5 for parts including extras) the set turned on just fine again.

As Nigel points out, that usually doesnt happen with Sony, but if you happen to take it apart it doesnt hurt to check. The top of the cap cans bulge slightly and sometimes there is some black or brown gunk around the cap top or bottom when they go bad, usually.
 

MrAl

Well-Known Member
Most Helpful Member
Hi again,

When my Sony CRT failed it was the main transistor for the high voltage section. Never checked the caps because it was only a year old.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Hi again,

When my Sony CRT failed it was the main transistor for the high voltage section. Never checked the caps because it was only a year old.
As we've said all along, Sony don't fit crap quality capacitors, so they don't fail :D

LOPT transistor failures on Sony CRT sets were commonly caused by dry joints on the line driver transformer, which is something you resolder if you ever change the transistor - apart from that it was almost always the LOPTX arcing internally, which instantly blows the transistor again.

My procedure was as follows:

1) LOPT transistor found to be S/C

2) Examine driver transformer VERY carefully for dry joints with a magnifying glass.

3) If dry joints, resolder, replace transistor, and see if it works.

4) If no dry joints give customer a quote for replacing the LOPTX and transistor (and STILL resolder the transformer as well).

Notice that if there were no dry joints I didn't even bother removing the S/C transistor.

A further complication was that it often blew the main-micro (a large SM device) - funnily, despite using the exact same chassis, it depended greatly if it was a 4:3 set, or a 16:9 widescreen set - I can't remember which way round it was, but one type killed the micro probably 50% of the time, and the other probably only 5% - weird or what? :D
 

MrAl

Well-Known Member
Most Helpful Member
Hi,

It's good to know at least one company stayed away from the cheap caps. They can really be a pain. I am surprised at how many products fail just because of the caps.
 

MrAl

Well-Known Member
Most Helpful Member
Hi,

That was done, and three or four of the electrolytic caps in the low voltage power supply were found to be bad, then they were replaced and the TV has been working ever since. I used better caps this time too.
 
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