Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

[johnboy1313]

I have a Sharp LC60E77UN that I picked up over the weekend. I'm excited about this one. It's the biggest TV I've worked on to date. The TV powers on and off with the power button. There is backlight and sound, just no picture. I suspect T-Con. The set apparently has two T-Cons, RUNTK4225TPZZ (the bigger squareish board) and RUNTK4221TPZA (the thinner board). I've found the SM, but can't find anything to help troubleshoot my no video problem, just specific inputs. Any help would be appreciated.

[tom66]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

The bottom board is a frame rate converter for the 120Hz feature probably.

The top board is the T-con board although it appears to use an FPGA (basically a fully customisable logic chip, not fixed structure) so its functionality may be different.

I'd check all regulators, fuses and make note of test voltages. You may want to consider borrowing the scope, as you can trace the LVDS signals and see if any are present or missing -- just a matter of seeing where they are going awry.

Several of the flat flex cables look a little dodgy, so I'd also try re-seating them.

[johnboy1313]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

I'm not sure if I'll be able to get the scope anymore. It's a long story but it had an intermittent no start issue that I had nothing to do with and it seems like the EE suspects that I did something to it. I may have to buy both boards and return whichever doesn't do the trick.

[tom66]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

You may want to consider investing in one, for around $50 you can get a decent analog one. It may also be the main board though that is relatively unlikely.

[dhallet]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

Any update on this repair?

[johnboy1313]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

Unfortunately, no. I haven't had the money to get a decent scope.

[tom66]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

You can get an analog scope for under $50
http://www.eevblog.com/2013/07/25/ee...scope-on-ebay/
which will be suitable for the diagnosis of the signals coming into and out of the t-con board.

[ijohannessen]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

johnboy1313, did you find the service manual on the internet somewhere? If so, do you mind sharing the link. elektrotanya only has a 3 page tech bulletin for this model.

Thank you.

[johnboy1313]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

I'm pretty sure I got it from Elektrotanya. I think I have it at home on my computer. To be honest, I can't be certain. If I have it, I'll break it up into smaller chunks and post it here tonight.

[budm]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

Big download:
http://elektrotanya.com/?q=showresul...oria=&kat2=all

[johnboy1313]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

Thanks Bud

[johnboy1313]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

I will have a scope tonight. Once I have it, what am I looking for to determine if it's a main/scaler/t-con board issue? Is it as simple as following the 12V to the panel with the scope?

[tom66]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

You would be looking at each of the LVDS data lines between boards, you can see the differential bus (traces tight together.)

If there's no activity on those from the main board, likely main board at fault (but rare, given sound), if there's no activity on the FRC motion processor (I think that's what the middle Sharp board is) then that's bad (if it's got input coming in), if nothing coming out of T-con (and it's got input), then that's bad.

[johnboy1313]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

You would be looking at each of the LVDS data lines between boards, you can see the differential bus (traces tight together.)

If there's no activity on those from the main board, likely main board at fault (but rare, given sound), if there's no activity on the FRC motion processor (I think that's what the middle Sharp board is) then that's bad (if it's got input coming in), if nothing coming out of T-con (and it's got input), then that's bad.

Are the data lines different than the power lines? Will there be any ground lines? I'll have to go through the SM when I get home.

[johnboy1313]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

I'll be completely honest here. I have no idea what I'm trying to do here. I believe the attached is the page that lists what each pin is for the main board output to the panel. Not sure which pins to probe.

[johnboy1313]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

Should the probe be on 1X or 10X?

[tom66]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

10X. You want to probe the TA1+, TA1-, TCLK+ etc. lines but you only need to probe one with a signal on it... you don't really care about what the signal is just if it is getting lost.

[johnboy1313]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

Should I connect a source? Without one, I'm getting nothing at all across any of them (from the main)

[tom66]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

It could make it easier.

[johnboy1313]

Re: Sharp LC-60E77UN Good Power, Backlight, and Sound, No Pic

I can't get the TV to change source to the DVD player I have hooked up. I can't tell if the input button just displays a menu that needs to be cycled through with the channel button or if the input button actually changes the source. With that said, there is absolutely no difference across any of the pins coming from the main. I don't really know how I should have the scope set up though. I'm not sure what the waveform would look like if there was a change.