BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

[Marsie]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

Anyone has a hint for me?

Tnx!

[Marsie]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

The tv is a Sharp LC-24LE240E

[Marsie]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

Hi, plugged in AV using the scart plug and got sound and able to control volume by rc!

[tom66]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

Plug a source into the set, do you get sound? (Even without pic)

[Marsie]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

So, got picture. Switched off.

Ordered 5404. Tv starts but no picture. Just a little flash of light.

Led stays green. 25V, 12V and 5V stay stable.

When powering off ( with remote control) : led flashes few seconds between red and green.
Than led stays red.

Powering on with remote control: few flashes between red and green.
Than stable green.

Doing this again gives same result again.

Anyone a hint?

[Marsie]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

That's right. It was only for a quick test....

[tom66]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

You can't use 1N5408 here. It's not a "fast" diode. You must use UF5408, HER308G, MUR460, or similar.
1N5408 will fail regardless of it having a resistor. It's just no good in a switching power supply output stage.

[Marsie]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

Got the same problem.

17PW80 V3 on SHARP LC-24LE240E


First I founbd out that diode D700 had infinity Ohm's.

Then one of the D708, D709 and D710 was shorted. Juste replaced with 3
( just for a quick test ) 1N5408. Got hot and 1 burned short.

So, I learned at school taht when palcing didodes paralel, each one needs a serie resistor, cause the slyhtliest difference in the Uf/If curve gives problems.

Each diode ahs its own Uf altough they are very small in difference. But as we know in the diode-curves, small variation in Uf makes a giant leap in If.

[dorango]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

I recently joined this forum as I just retired. My granddaughters tv packed up so I thought this would give me something to interest and occupy me for a while. I followed the information on this thread, I have just fitted the diodes and it works Thanks everybody for the help I feel really delighted as I was mostly a manual worker using tools and parts not so delicate. Now the TV her friend gave her to use has no sound so now I'm off on another mission THANKS again dorango

[il_dabra]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

Hi!
I'm writing this post because i've got a problem with this power board, but i've got the v3 revision (it comes from a sharp LC-24LE510E led tv).

I was using it, then suddenly the tv died.

I've checked the capacitors and the uf diodes, but the standby led is still dead.

I've also checked the power on the ic700, and it goes up and down from 10 to 16 V.
I've replaced also C715 due to the fact i believed it was the problem, but still nothing.

Any help is highly appreciated!
Thanks from Italy

[oddbodd]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

Yes, I've been reading about the number of different applications for this board, all with their own firmware, so it's unlikely I'll find the correct replacement.

Is it worth pursuing the problem on this board, or am I likely to be wasting my time?

If not, is there anything else I can test?



Note: I've powered it on this afternoon, and initially there was a fair bit of flickering. I've gone through the on-screen menus, trying different picture settings etc. Some settings make it flicker more quickly than others. "Normal" seems to be the best setting. "Game" and "Dynamic" flicker much faster. "Cinema" can also make it flicker.

Anyway, the picture stabilised in "Normal" setting, and is OK at the moment. Although I did notice that for a short period that the picture was brighter in the centre than at the sides. Dividing the picture into roughly 3 vertical sections, the 25% at each side was slightly dimmer than the centre 50%, if you see what I mean. That didn't last for long, though.

I shall leave the TV on for a couple of hours to see what happens.

[tom66]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

There is a schematic HERE:

Spoiler: on the main CPU...

Vestel 17MB62 isn't the most reliable main board out there...... and if it does go bad, good luck finding the right replacement, because there are so many different versions.

[budm]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

I could not tell you where the BL_ON is generated on that board without diagram.

[oddbodd]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

Mainboard 17MB62-2.6 pic.

[oddbodd]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

OK, hopefully nothing I did, then

Mainboard is 17MB62.2.6

[budm]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

BL_ON is a steady state signal, it is either HI or LO, it can be that the Transistor or the MOSFET switching device is defective, nothing to do with refresh rate.

[oddbodd]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

Thanks budm,

Could this have been caused by connecting the TV to a PC via VGA cable... something to do with differing refresh rates?

[budm]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

OK, PL706 PIN 3 is BL_ON and this signal goes out to the LED driver board.
The BL_ON is generated by the main board and it is fed to PL703 pin 15 and routed through a resistor then to PL706 PIN 3.
It looks like the BL_ON is active LO (LO= ON).
So you have BL_ON signal problem from the main board.

[oddbodd]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

No marks on the board, I'm afraid.

I've attached some pics of the power supply board, if that's any help.

Pics 1 and 2: Top right-hand corner, pin 3 of PL706 is the 3rd pin from the left.

Pic 3: Underneath, 4th solder joint in the row of 6, top left-hand corner.

I can't quite make it out, but I think the schematic says B/L_ON/OFF for pin 3 [top right-hand corner].

Edit: Aha... just found the pdf version of the schematic [attached].

Pin 3 = BKL_ON/OFF
Pin 4 = PWM_DIM

[oddbodd]

Re: BUSH LED2497ODVDFHD, 17PW80 V2, Dead!

I'm not sure if they're marked, but I'll have a look tomorrow.