Toshiba 55L310u Noise/Snow in Picture

[mmartell]

Tv works normal except for the green snow in the picture. Not everywhere at once maybe following darker shades or similar.

Tcon is integrated in the panel boards but I did measure gamma 1-14 and they're ok. Also 1.3v and 3.3v present there. VREF is 16.3v.

Main board processor is NOT a bga so it's not that but It may be failing internally.

Thoughts on whether I should go with a replacement board or further investigate the tcon ?

[jjanssen7]

Re: Toshiba 55L310u Noise/Snow in Picture

play around with the LVDS cable... sometimes that style develops a dodgy connection. Looks like Tcon to me otherwise...

[mmartell]

Re: Toshiba 55L310u Noise/Snow in Picture

Don't see anything wrong with the cable definitely pulling and replugging doesn't make a difference.

I should have said the artifacts are not seen at startup they appear within a couple of minutes of turning on so related to something heating up. I put a heatsink on the main processor didn't help.

Could probably use a Flir camera but don't have one of those.

[mmartell]

Re: Toshiba 55L310u Noise/Snow in Picture

Had another very similar lvds cable on hand. Swapped it in and still had the sparklies.

Assuming for a minute it's a tcon problem any suggestions on how to troubleshoot it ?

[mmartell]

Re: Toshiba 55L310u Noise/Snow in Picture

To try and eliminate the main board as the problem I Frankensteined in an RCA main board.

Looks great if you're on LSD.

I went into the service menu and can make changes to the panel type but of course there's no going back should I make the wrong choice...

Have a few more candidates before I quit this approach.

[dick_barton]

Re: Toshiba 55L310u Noise/Snow in Picture

I'm sure there was a problem very similar to this one sometime in the year which concluded that the fault was down to the mainboard and a replacement mainboard cured it.

[mmartell]

Re: Toshiba 55L310u Noise/Snow in Picture

I am leaning toward mainboard too but was trying to get a decent pic from an alternate mainboard to rule out the tcon definitively.

[ikmpch]

Re: Toshiba 55L310u Noise/Snow in Picture

I am leaning toward mainboard too but was trying to get a decent pic from an alternate mainboard to rule out the tcon definitively.

I would suggest firmware update/reset for the tv main board first. If you can get the service manual, I would check all the components on the main board and also check voltages produced and sent to T-CON board. Good luck.

[mmartell]

Re: Toshiba 55L310u Noise/Snow in Picture

Replacement main board produces the exact same issue. Problem must be on the tcon.

[nomoresonys]

Re: Toshiba 55L310u Noise/Snow in Picture

I think it's a tcon issue, just had a similar deal with a Sanyo, had the even horizontal lines, replacement tcon cleared it up.

[matt88]

Re: Toshiba 55L310u Noise/Snow in Picture

Hello sorry guys new here could anyone please help me identify the problem of my toshiba power tv 44 inch

[mmartell]

Re: Toshiba 55L310u Noise/Snow in Picture

Don't know how I missed this but this ic probably the gamma ic labelled i1991 is sensitive to temperature swings. Heating it causes the pic to bloom almost white and cooling it with a shot of upside down canned air snaps the pic back to beautiful with zero artifacts. It didn't feel hot to the touch though which I find odd.

I removed it and put it back and the pic looks great but the ic is roasting hot now, can't keep a finger on it.

Anyone know anything about this ic or know of an alternative ? It's a QFN32 package.

[mmartell]

Re: Toshiba 55L310u Noise/Snow in Picture

And here's a pic of it...

[mmartell]

Re: Toshiba 55L310u Noise/Snow in Picture

I put one of those thick heat transfer pads you find under YSUS boards on this ic and it's running HOT, the rubber is almost too hot to touch!

It's running though without artifacts but I'm afraid to leave it unattended in case it catches fire lol. Maybe these chips run very hot under normal operation ?

Edit: NOT normal. I was starting to see a darkish spot at the bottom of the lcd panel where the gamma ic is. Definitely running too hot!

If anyone has one of these I would like to purchase it instead of waiting for shipping from China as Aliexpress is the only place I can find it.

[jjanssen7]

Re: Toshiba 55L310u Noise/Snow in Picture

I can look for one of those in my scrap TV pile and ship it to you... PM me if interested. I'm in Chilliwack, B.C.

[dick_barton]

Re: Toshiba 55L310u Noise/Snow in Picture

Hello sorry guys new here could anyone please help me identify the problem of my toshiba power tv 44 inch

Hello Matt88
You will need to start your own thread and give as much information as possible ie description of the fault, any voltage readings taken, some photo's of your boards.

[mmartell]

Re: Toshiba 55L310u Noise/Snow in Picture

This has been resolved by changing out the IC in question.

Big shout out to jjanssen7 for tossing one in the mail to me from a scrap set he had on hand.

Thanks for everyone's input.

[nomoresonys]

Re: Toshiba 55L310u Noise/Snow in Picture

Very nice save.

[ReeceyBurger123]

Re: Toshiba 55L310u Noise/Snow in Picture

Nice one brilliant diagnoses, seeing a lot of panel mounted PCBs ending up faulty with Ic and ceramic cap faults, plus I hate working on them

[mmartell]

Re: Toshiba 55L310u Noise/Snow in Picture

Hair dryer - handyman's secret weapon

Yes not very practical to work on them with bench tools. I had to make a temporary bench with a couple of sawhorses and a piece of plywood so I could get the thing in position to be repaired.