Sony kdl32l4000 tcon or inverter?

[tucocaps]

This set has a punched-in damaged panel.

Powers on. Mainboard and psu seem OK as I'm able to get sound, remote activity , etc.

Backlight flashes briefly on power up, but then goes dark.

I'm wondering if I can somehow test/isolate the inverter and the tcon to know if one or the other is likely OK. Thanks for any help!

[techman1025]

Re: Sony kdl32l4000 tcon or inverter?

Hi ....known problem JUST REPLACE T401 inverter transformer (PN 1-857-109-11) very inexpensive ..this will fix your problem
Techman1025

[tom66]

Re: Sony kdl32l4000 tcon or inverter?

If the panel is badly damaged a bulb may be cracked... this will cause this symptom.

[tucocaps]

Re: Sony kdl32l4000 tcon or inverter?

Does it seem like the TCON is probably OK, but the inverter is damaged, based on the symptom?

[Alastair E]

Re: Sony kdl32l4000 tcon or inverter?

If screen is smashed--you cant tell about T-Con!--That does the picture, but if panel smashed--you'll not have a picture regardless!

IF a bulb has gone--will give 2 sec to black regardless of whether the BL board is OK.--Thats to say, the BL board could still be faulty but you'll not be able to tell--IF you've got a broken bulb...

Then again--IF you plan to fix--You'll be replacing all this lot anyway!.

[tucocaps]

Re: Sony kdl32l4000 tcon or inverter?

thanks alastair! I guess that's how the cookie crumbles when you have a broken panel. No real way to test TCON, and in some cases the inverter. Well, I heard the inverter can be tested with a bunch of bulbs ... but I'm not sure building that rig is worth it for me just yet.

[lookimback]

Re: Sony kdl32l4000 tcon or inverter?

These older Sony's also have protection circuits. So, you could have a fault on any of the boards and still have the backlights fire. They should attempt to start 3 times, and then the LED will flash a code and the TV will go into protection mode. At that point, you have to disconnect the power source to reset.

[tucocaps]

Re: Sony kdl32l4000 tcon or inverter?

kimback: Well, this one isn't going into protection mode. Also, I've found in most cases that the TCON is OK when the screen is cracked. However, I'm now realizing that I am making a pretty big assumption there. Even so, I've sold several from cracked screen units, and no complaints yet. Got a bunch on the shelf too.

[lookimback]

Re: Sony kdl32l4000 tcon or inverter?

In my experience, even with a broken screen, it's (usually) possible to determine whether a Tcon is good or not. Of course, you can't test it 100%. Usually, unless you have a straight horizontal crack across the top (or bottom if that's where the TABs are), you can see enough of the picture to make an educated guess. That's saying, your average accidental damage, not the "I got into a fight with my gf and she smashed it with a hammer." (I've seen a few of them too).

[tucocaps]

Re: Sony kdl32l4000 tcon or inverter?

kimback: that's a good point, and I've definitely tried to see what I can see with a cracked screen that's still "working". However, if I understand this right, if there is major screen damage and the BL won't stay on, then you are probably looking at a broken bulb. In that case, you can only "bench test" the inverter (with lamps), but can't really see anything regarding the TCON?

[lookimback]

Re: Sony kdl32l4000 tcon or inverter?

Yes, you are correct. With no backlights, there's not much you can do. Depends on the design, but sometimes you can manually turn the inverter on using a 5k resistor, just as you would jump ps_on. On the older Sony's (not sure about newer ones), what's often mistaken for inverters are actually balancer boards, and the transformers which power them are usually on the PS or, in some, are on separate boards.