Sony KDL-46ex600 T Con fuse blows

[DakotaKid]

I got this TV and it would power on, gave 5 blink error which indicates bad T Con. I found the 3A fuse on the T Con blown so I soldered a fuse holder with 3A inline and powered on the TV. The picture and backlight came on and showed "no signal message" and other info. The picture showed a lot of bleeding and blotches though the panel seems to be ok as far as no cracks or anything. After about 30 seconds the T-con fuse blew again and now it is back to the 5 blink error code.

There is no visible damage on the T-con board top or bottom but it doesn't seem to be displaying a clear and proper image before the fuse blows. Is there something I can check, e.g. 12v input or something to diagnose whether it is T Con board or a different problem?

Thanks in advance.
DK

[budm]

Re: Sony KDL-46ex600 T Con fuse blows

There should be switching power supplies on the T-CON board, you can tell by the round/sq inductors. You may have bad SMPS IC for those supplies or shorted loads.

[DakotaKid]

Re: Sony KDL-46ex600 T Con fuse blows

Thanks budm. Pictures posted. I took a closeup of the inductor coil that seems to be a little discolored though I cannot tell for sure. Is there a way to test these? If I measure across them on the exposed terminals, both show 0 ohms. Is this worth repairing or should I be looking for a replacement board?

DK

[budm]

Re: Sony KDL-46ex600 T Con fuse blows

I would disconnect those two white ribbon cables that go the panel, then put in the new fuse and see if the fuse will still blow (you can set the meter to DC AMP mode (put the probes in place of the fuse) so you can read the current draw), if not, it may have bad TFT drive ICs. I can see that it has 3 switching power supplies.

[DakotaKid]

Re: Sony KDL-46ex600 T Con fuse blows

I would disconnect those two white ribbon cables that go the panel, then put in the new fuse and see if the fuse will still blow

Thanks. I went ahead and put another fuse in and disconnected the two ribbon cables. I powered it up and it does NOT blow the fuse. The TV stays on with green power light, backlight stays on until I turn it off. If I read your last comment right that indicates is probably the TFT drive IC's. Are those part of the Tcon or (gulp!) the panel?

DK

[tom66]

Re: Sony KDL-46ex600 T Con fuse blows

They are part of the panel. You can try with only one ribbon at a time to narrow it down, it may be a bad driver IC or it may be a component like an MLCC failed (ceramic SMD capacitor.)

[DakotaKid]

Re: Sony KDL-46ex600 T Con fuse blows

Thanks tom and budm. Making progress! I have attached pictures. With left hand ribbon connected and right hand disconnected I get perfect picture on left half of screen. With left disconnected and right connected I get as shown in the picture. Definitely something wrong with the right hand side of panel / drivers / tcon. Hope this helps you guide me to next steps.

Thanks.
DK

[budm]

Re: Sony KDL-46ex600 T Con fuse blows

That is bad panel TFT drives, I had the same problem in LG 47", see post 10

[tom66]

Re: Sony KDL-46ex600 T Con fuse blows

I think you have a defective tab driver #6 from the left. Probably not repairable unfortunately. You can try checking for obvious shorts but the IC is probably bad.

[DakotaKid]

Re: Sony KDL-46ex600 T Con fuse blows

Well that's a bummer. The half that works sure looks great. LOL. Guess this one is headed to the junk pile. Thanks for the help!

DK