Re: Sceptre X505BV-FMDR



Since inverter keeps constant current for BL, not constant voltage, I just shorted out failed LED. Missing one of 70 - it's 1.42% drop in overall brightness and voltage. Not a big deal. Since it's between other (good) LED, behind diffuser and about 2 inch from LCD panel, darker spot is almost invisible on screen. As I understand electricity, it shouldn't make other LED work harder as current through them stays the same unlike in Christmas lights with shorted bulb

However now I have a different problem. Screen has three vertical...

Re: Sceptre X505BV-FMDR



That explains...

I just asked that seller on eBay if he can give me a full datasheet or tell maximum current for those LED. Will look forward for his response

BTW, what is normal backlight voltage for Sceptre x505?

I don't remember exactly how many LED total there. It looks something about 60. So counting 60x2.4V should be about 144V total, shouldn't it?

How 300V peak at starting inverter wouldn't kill them unless 300V is just idle voltage?...

Re: Sceptre X505BV-FMDR



Seller due20150801 on eBay where I purchases 2835 LED posted 20ma. Perhaps that was just current used to measure front voltage, not max ampreage. Other dastasheets found in Google show 80ma, 120ma and 240ma as max value.

It looks like max current very depends of manufacturer and not sure what is max on mine.

Interesting, how BadGoo (the name of author in one of postings on this thread) used 2835 LED for such repair of similar TV and they didn't burn?

Since I still have 96 of them for 6 cent a piece,...

Re: Sceptre X505BV-FMDR



20ma/3.4V front voltage max for replacement LED 2835

The problem is that random LED's burn in random BL strips, not a replacement LED...

Re: Sceptre X505BV-FMDR

I have exactly same problem with the same Sceptre X50 TV as topicstarter reported on the first page. I found a bad LED in backlight strip and replaced it with 2835 LED as it was recommended in this thread. 100 LED's were found for $6 on eBay

I don't have low temperature soldering compound and used regular eutectic tin-lead 60/40 compound. Burned 3 LED's with practicing before learned a proper technique to solder them. 4th LED was successful and backlight was restored. I assembled TV back and it turned on as normal. However after about 3 minutes...

Re: New Members - please post your introductions here

Just joined here looking how to fix BL in Spectre TV. Graduated from University of Radio-Electronics in 1987. Worked as developer of computer and other digital cirquitry. Then server admin for decades however continue Electronics a a hobby. I'm glad I found this forum. So much helpful information vs. of marketing bu11$h1t from majority of other sites