Sharp LC-52LE640U - Inverter/Lamp system failure

[wcsd106]

Hello All,

Thanks for taking the time to read my thread and I hope I can find some good information. I have been coming here for a long time just never took the opportunity to register.

Here's the system I'm dealing with right now:

Sharp LC-52LE640U LCD Television

Symptoms:

When power is applied, the 'V' indicator blinks 1 long and 1 short which, per the service manual, is indicative of Inverter/Lamp system failure.

I've done a preliminary look over the main board and have not located any capacitors with obvious defects.

I will have more time to troubleshoot the set tomorrow morning, but am hoping that someone can point me in the general direction.

The main board of the set is a RUNTKA931WJQZ / DPS-152DP which is a Power Supply / LED Board. I believe my problem should be isolated to that main board.

Any replies will be greatly appreciated, and I will endeavor to provide any information requested to better reach a solution.

Thanks.

[wcsd106]

Re: Sharp LC-52LE640U - Inverter/Lamp system failure

FYI: I am able to access the adjustment process mode (Service Menu) by holding the INPUT and VOL - buttons on the side panel down while applying power to the set.

I will take some photos of the menu.

[wcsd106]

Re: Sharp LC-52LE640U - Inverter/Lamp system failure

For what it's worth, the Lamp Error counter was at 5 (Maximum allowable) I have reset the lamp error counter and the TV is now powering on... I am going to try extended powerup (watch a movie) as well as turning it off and on to see if I can cause the error to reappear.

[ccain]

Re: Sharp LC-52LE640U - Inverter/Lamp system failure

Hi, new member here and an EXTREME amateur electronics enthusiast.
I stumbled upon your thread and this forum trying to answer the very same issue. A lot of OUTSTANDING info on this forum BTW. Thank you for that!

Anyway,

I have the same exact unit and have the same error code. The only difference is that for a couple of days prior to the TV defaulting into standby mode, I noticed a dark portion of the screen in the lover left hand side.

Logic dictates (to me anyway ) that a bad inverter board could create a dim spot on the screen but I haven't ruled out lamp failure.

So, I tear into the unit. I've had the power supply board out a couple of times to inspect it. I haven't run any diagnostics on it yet because I lack the proper meter at this time (Amazon is your friend and it'll be here in a couple of days)

Anyway, looking at the power supply unit, I can't detect any faulty capacitors or anything like that, visually (I know that doesn't mean anything). BUT... I can boot the TV up in bypass service mode (CH dn + Vol up) and the backlights come on and what not. That got me thinking that the PSB was in itself OK. Once you unplug and try a fresh start up, it defaults back into standby mode and the LED flashes again.

Still searching the net, I read that sometimes the inverter board can have grounding issues and, as I hadn't taken it out yet, I thought I'd have a look at it. So, I remove it, everything looks ok but when I reinstalled it, something different happened. Now, when you put it into service mode, the left side of the screen lights up from the midpoint and fades to black on the extreme left side for about a second and then the TV defaults back into standby and the LED flashing continues.

If you try to use the bypass mode, the same image appears then fades away.

Perhaps I have stumbled onto the culprit by sheer dumb luck and will now be looking at replacing the Inverter Control Board. What do you guys think?



wcsd106, did you ever get your issue resolved?

[Ltank]

Re: Sharp LC-52LE640U - Inverter/Lamp system failure

This is a LED LCD TV correct? The dark spot most likely a Led backlight is out. They are considered part of the screen. You would have to open it and try to replace it with the closest thing that might work. LEDS must be heatsinked.

[ccain]

Re: Sharp LC-52LE640U - Inverter/Lamp system failure

Hey Ltank, yes, it's an LED LCD TV.

Update. I pulled the mainboard today and found something very interesting. The printed circuit board shows signs of extreme heat around the Mediatek ARM. I mean, this thing got HOT. Hot enough, in fact, to bubble the coating on the board and discolor the board for about 3/4 of an inch all around. The metal cap on the ARM shows bluing around the edges and there is a decent amount of discoloring on the circuits leading from the ARM to the connector that connects to the TCON. Interesting.

[Alastair E]

Re: Sharp LC-52LE640U - Inverter/Lamp system failure

Hey Ltank, yes, it's an LED LCD TV.

Update. I pulled the mainboard today and found something very interesting. The printed circuit board shows signs of extreme heat around the Mediatek ARM. I mean, this thing got HOT. Hot enough, in fact, to bubble the coating on the board and discolor the board for about 3/4 of an inch all around. The metal cap on the ARM shows bluing around the edges and there is a decent amount of discoloring on the circuits leading from the ARM to the connector that connects to the TCON. Interesting.

Sounds like someone tried reballing/reflowing with a blowlamp!

--May or may not be related to the fault, you'll need to get that test-meter and track the fault down....

[mattstolte]

Re: Sharp LC-52LE640U - Inverter/Lamp system failure

any luck on what the problem was I am dealing with this issue myself

[wcsd106]

Re: Sharp LC-52LE640U - Inverter/Lamp system failure

Still unsure of the problem. Resetting the lamp fail error count to zero made the TV work again, but a couple of weeks ago it had the same problem once again. Another reset and the TV is functioning, but something is causing the lamp error count to rise.

I'm all ears if someone has a suggestion as to what to look for.