Me wrong or ShopJimmy?

[capwizard]

Me wrong or ShopJimmy? Does anyone know the answer??

LG 42LE5300 my tested result shows : 19 X 12, Total LEDs = 228 LEDs , but ShopJimmy's picture shows 52 X 4, total LEDs = 208 LEDs

Voltage needs wait 1 min. = 105.7v, one LED votage = 5.54v
How many LEDs in an array = 19 LEDs, How many arrays = 12, Total LEDs = 228 LEDs

PS: This edge screen has twins LEDs, all the led arrays worked OK, so I won't open the screen to find out the answer!

LG 42LE5300 service manual:
https://www.electronica-pt.com/esque...artdown/24431/

[petehall347]

Re: Me wrong or ShopJimmy?

no idea sorry .
p.s what is that board for on your meter ?

[capwizard]

Re: Me wrong or ShopJimmy?

Poormans LED TV Backlight Tester.
https://www.badcaps.net/forum/showthread.php?t=59136

[petehall347]

Re: Me wrong or ShopJimmy?

looks good until you go and touch it whilst on .

[capwizard]

Re: Me wrong or ShopJimmy?

Electroshock therapy treatment help poorman be rich and add some more memory.

[petehall347]

Re: Me wrong or ShopJimmy?

these damn switch-mode supplies give me a shock if i get nearer than 5 inches away with my hand .
turn them led lights down and forget how many are in there . pain in the arse stripping panels to change them .

[budm]

Re: Me wrong or ShopJimmy?

5.54V for Dual -LED, you are getting that may be due to you are not running at close to max If so the calculation comes out wrong?
I.E. Look at Vf VS If chart.
https://cdn.badcaps-static.com/pdfs/...4398d8add2.pdf

[capwizard]

Re: Me wrong or ShopJimmy?

"you are getting that may be due to you are not running at close to max If so the calculation comes out wrong?"

Ive set Tester current at 6.8 mA for safety reason, normally single LED should be at 20 mA -30 mA, but total LEDs test current also low, calculate results that are aiming for unknown values, the percent error formula turnout to be pretty accurate.

"Not running at close to max" that did bother me, then I found out testing at 5ma, 10ma, 15ma, and 20ma the result almost the same, and can accurately predict the number of LEDs, but not the total power consumption. Thank you for your response.

[budm]

Re: Me wrong or ShopJimmy?

"normally single LED should be at 20 mA -30 mA" Not these White backlights LEDs they run at 200~400mA.
Lower current = lower Vf so your cal for the qty of LEDs will be off.

[capwizard]

Re: Me wrong or ShopJimmy?

You're the Best! it's hard to believe that TV industry put up the current so high to get what they want, every time I saw the spec. I thought that was A misprint! In my case, LEDs current is at 55mA.

From ShopJimmy: base on AUO's panel T420HW07 V.1 it is 208 LEDs. He is right!.....

ShopJimmy's picture shows 52 X 4, total LEDs = 208 LEDs is for Panel Sticker Number: T420HW07 V.1 LG/Vizio T420HW07 V.1 LED Strips - 4 Strips

From my calculation: base on LG's panel LC420EUH it is 228 LEDs. im right!.....

Voltage = 105.7v, one LED voltage = 5.54v, how many LEDs in an array = 19 LEDs, How many arrays = 12, Total LEDs = 228 LEDs

PS: My LG 42LE5300 TV LED screen till unopened..... WHY! they use different brand of panels? Because they sale so many TVs all over the world , always out of the supply.

Reference:
LG's panel LC420EUH


From ShopJimmy:
Important Message: PLEASE make sure the LED panel in your TV matches the information in this listing before ordering. DO NOT simply order by model number, as this may result in receiving LED strips that are incompatible with your TV.

[budm]

Re: Me wrong or ShopJimmy?

If you look at the chart (LC420) when the LED string are driven at 55mA (TYP.), the Vf is 117.8V (TYP.).
The T420 is driven at 120mA (typ), Vf for one string is 88.4V (TYP.)

[capwizard]

Re: Me wrong or ShopJimmy?

You are so smart, I saw that and i talk to myself don't waste my time to mention it, nobody will pay attention to it.......