Sharp 70' LEDs Spike 260v at start up?

[Diah]

Re: Sharp 70' LEDs Spike 260v at start up?

who asked you to bring replacement MB ??? yours problem not at it.. send it back and put your original MB.

other wise please if i tell you on some things i do know... don't ask how it will work.. i am not kidding. it is science too.

i did explain it several time the spike at start up who cause it and what are the result.. if we don't bring some things in circuit to eat this spike then LEDs will day after day toasted .... i suggest to you this method only because your screen huge. if you take it out 99.9% will damage . go back to your first threat where i explained how to do.

[JayPoorJay]

Re: Sharp 70' LEDs Spike 260v at start up?

In the first thread you suggested putting a table lamp in series. I'm willing to give it a try - but I need specific instructions/directions. How do I do that?

[vinceroger69]

Re: Sharp 70' LEDs Spike 260v at start up?

Hey Man, Hi...

It's a standard US table lamp,,, I can put whatever size and style bulb in it that you suggest. I'm in the USA,,, so it's 110/120V, around. Having a clear understanding of the wiring is what I mean. And an assurance that this is something that will actually work... Never heard of such a thing.

What's the reason that putting a filament bulb in series works?
How does it work?



On another note - got the MB in the mail, installed it, and it APPEARS to be a dud... No matter how I tried to boot up the TV I was unable to get the screen,,, light or dark,,, to display anything that would allow me to reset the TV, see the menus, or start it up in the special K screen where the "Industry Init" option is displayed,,,, well, anyways. The power light on the front of the TV came on and stayed on nicely. Just NO kinda image what so ever. Replaced the OLD board and things went back to "normal". A normal broken tv, lol.

Any suggestions, new main board initial setup? I'm all ears. Or, I'll return it tomorrow or Friday AM.

Again. That's to you all. I really really y'all sharing your hard worked for wisdom, knowledge and experience.

Peace

i would return that non working board and get a full refund and try the lamp method suggested removing a 70in lcd is your last option in my opinion as very high risk of cracking it etc.

[JayPoorJay]

Re: Sharp 70' LEDs Spike 260v at start up?

So, with a better method of communication, Diah and I worked thru the lamp method. No good result. Tried all three channels/groupings of LED leads, working on the MINUS side placing a lamp with 60watt and 35watt bulb, in series.

TVs indicator would blink on initial plug in, then when force started would try and power up (LEDs lighting) then powering down. Shining a light on the screen an image could be seen.

I am willing, and it seems the only option is to open the TV, remove the screen (risky) and try to match the LED strips. Test them. Then determine whether to source NEW complete strips is the best option, or to replace individual LEDs on the OE strips. I like the second option. As I understand it, complete strips for the TV have always been unobtain-ium... Then, do I get 100 new individual leads and work the daunting task of replacing the ALL, or just the few that have gone south.

At a crossroads.

[Diah]

Re: Sharp 70' LEDs Spike 260v at start up?

So,

there are somethings wrong.. can you show me the powerboards lable you installed.. and the original one. there are 2 version of PCB one for 60 size and other for 70 .. both identical but the BL spike are different

[JayPoorJay]

Re: Sharp 70' LEDs Spike 260v at start up?

I'm at work now, but will when I get home. I was pretty careful about comparing and checking the p/n's,,,, but anything is possible. Thanks!

[JayPoorJay]

Re: Sharp 70' LEDs Spike 260v at start up?

Hello again y'all.

I traveled for a few days so have been away from the monster...

To Diah... I have the MB with it's brackets all back on the TV and to get photos of the OE board part numbers I would have to disassemble again. Now, tonight, I just don't have the energy for that. Worked all day and weekend.

Q: Is there anyway to KNOW which individual/single LEDs would be the correct replacements BEFORE taking the screen off the TV? I communicated with Shop Jimmy and they said complete sets were never made.

I ask because I would absolutely prefer to have the screen off the chassis for as short a time as possible. I would like to repair (if I can even do this) and replace the LEDs and replace the screen in one shot, if you know what I mean...? I don't want to have to wait a week between having the screen off and laying around while I wait for the replacement parts.

Neeeerve wracking, this thing is.

[JayPoorJay]

Re: Sharp 70' LEDs Spike 260v at start up?

Here is the info off the 2 boards.
They're identical, unless I'm missing something.

[nomoresonys]

Re: Sharp 70' LEDs Spike 260v at start up?

That info does not tell the whole story, you pretty much MUST go by the info on the white sticker, that printed board info is what they start with, then they populate acording to need.

[nomoresonys]

Re: Sharp 70' LEDs Spike 260v at start up?

Might very well have a mismatch.

[nomoresonys]

Re: Sharp 70' LEDs Spike 260v at start up?

https://www.youtube.com/watch?v=izaPfMU6hHE

[JayPoorJay]

Re: Sharp 70' LEDs Spike 260v at start up?

Good Morning... I watched the vid and had another look. No completion type bar code style sticker like in the Samsung. All I saw were these. I'll post what I did see. I'll have a close look after work.

Also, I reached out to the guy from the eBay link above and he feels fairly confident that his strip will match mine. When I suggested the plan of using his strips and SAVAGING the remaining LEDs I would need and soldering them into the remaining board (if need be), he said his own success rates doing this are 50/50...? $75 bucks a pop for the strips and I haven't seen anymore anywhere.

[nomoresonys]

Re: Sharp 70' LEDs Spike 260v at start up?

If your edge lit leds are tiny like this sony I'm currently messing with, I'd say getting whole strips is best plan, maybe see what the backlight pros here say but I'd go whole strips.

[JayPoorJay]

Re: Sharp 70' LEDs Spike 260v at start up?

Hey, NoMore... All the pictures I've seen, and there ain't a lot, are larger rectangular style with like 4 clear solder joints at corners... The guy has 2 strips that are advertised as being 100%. But who knows...

If I were to purchase it would bring me to $200+ in. Still not too too bad. But still I am hesitating. Then, finer solder, flux in a needle, better iron and a hot plate of some kind are on the shopping list - suction cups X4, and FEAR of breaking the damn thing anyways. Fun fun.

[nomoresonys]

Re: Sharp 70' LEDs Spike 260v at start up?

I see, well in that case, using new leds would be better than used, go for the singles then if it's bad backlight/s.

[nomoresonys]

Re: Sharp 70' LEDs Spike 260v at start up?

.

[nomoresonys]

Re: Sharp 70' LEDs Spike 260v at start up?

The harbor freight suction cups should be fine, no need for the fancy overpriced ones.

[JayPoorJay]

Re: Sharp 70' LEDs Spike 260v at start up?

The harbor freight suction cups should be fine, no need for the fancy overpriced ones.

Yup. Thanks

[Diah]

Re: Sharp 70' LEDs Spike 260v at start up?

70 size PCB should labeled some where with KB131W the small size KB119W

the early strings i think they used almost double LED 6,v 7030 100 pieces less than 6$ 200 pieces enough to replace all. only need the iron tips 0.1mm and solder wire thickness less than 0.5mm to have clean work. plus consider if you like it or not, you will burn nail or finger. LOL

[vinceroger69]

Re: Sharp 70' LEDs Spike 260v at start up?

https://www.aliexpress.com/item/32445357361.html
something like this may work but what what and colour type im not sure plus you need too check anode and cathode matches your leds used