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View Full Version : Guide: How to repair the uneven (left-right and vice-versa) brightness.



gsv883
05-02-2012, 11:16 AM
NOTE: This Guide was not made by me, but rather this was a guy from Russia who did the mod to correct the uneven brightness on his Yamakasi Catleap, it SHOULD work on the other Korean monitors having the same problems.

The Korean monitors all suffer from uneven lighting, such that your monitor is bright on one side then gets darker as you move to the other end of the monitor, for most of us, this is not noticeable unless you set your screen's brightness from 0-3 clicks.

Here are extreme examples of what I am talking about:

http://cdn.overclock.net/6/6d/6d1bb4a7_Snapshot_20120404.jpeg
As you can see, the right end of his screen is darker than the left end.

http://cdn.overclock.net/c/c5/c52952c0_yamakasi_2560_light_proglem.jpeg
This one suffers from right-to-left screen darkening.

To resolve this, you have to do the following:
1) Swap resistor #113 (43k Ohm) with a 100k Ohm resistor.
2) Solder one end of a 100k Ohm resistor to the terminal of transistor #103.
3) Solder a 0.1 - 1 micro-Farad capacitor to the free end of the resistor in step 2.
4) Unsolder diode #704 and put this diode in place of resistor #725 (220 Ohm). White striped cathode will be on the right relative to the picture.
5) Connect with a wire the capacitor from step 3 to the left terminal of the empty diode terminal #704.

A rough diagram of the steps as mentioned above.
http://cdn.overclock.net/d/d0/d028beb6_f56099005969.3.png

This is how the portion looked like before it was corrected
http://cdn.overclock.net/e/e9/e91782e0_8efb3c0eb8de2.jpeg

CAVEAT
Do this at your own risk

Sn0_Man
05-02-2012, 11:22 AM
Thanks for posting!

Is this a 2B board in the pictures?

HyperMatrix
05-02-2012, 11:32 AM
Thanks for putting the guide up mate.

gsv883
05-02-2012, 01:00 PM
I think it's a PCB from the 2C model.

Taker
05-09-2012, 10:10 AM
It looks great on the image point # 3. It can be seen very well as the capacitor is soldered.Some guide for Dummies?

namlocnz
05-10-2012, 02:27 AM
if our monitor had an extreme case of this would that warrant return to base?

Junkboy
05-10-2012, 02:32 AM
if our monitor had an extreme case of this would that warrant return to base?

I would hope your extreme cases that it would but depends on severity, I think this will be one of those things we'll find for sure when it unfortunately happens to one of us.

whitespider
05-10-2012, 02:38 AM
I would hope your extreme cases that it would but depends on severity, I think this will be one of those things we'll find for sure when it unfortunately happens to one hundred of us.
Fixed. ;)

Junkboy
05-10-2012, 02:42 AM
Fixed. ;)

If it happened we would have a mutiny on our hands. :D

I would kinda hope they would turn these on and check your sever issues though, we'll know soon enough.

goji
05-10-2012, 04:07 AM
Really hoping I don't have this problem, I would much rather have some dead pixels and or backlight bleed.

Brian
05-11-2012, 08:38 AM
Has anyone with a 2B had this issue?

Dougiet
05-15-2012, 06:44 PM
Step 3 /5 is the capacitor being soldered to the wire and resistor only? or is there something else going on there?

Shadman
05-16-2012, 05:27 AM
Step 3 /5 is the capacitor being soldered to the wire and resistor only? or is there something else going on there?

I believe so, but I'd wait til someone else says yes first.

Taker
05-25-2012, 03:14 AM
Someone who has done can give more information and a picture of the completed work. I did not clarify a few steps from the first post.

P.d: You can do this mod with no SMD components?

NightFox
05-25-2012, 03:31 AM
gsv883, (http://www.120hz.net/member.php?128-gsv883)

Pictures are in fact larger. Please make them clickable.

Addition
The original resolution pictures:
http://s019.radikal.ru/i609/1204/0b/f56099005969.png
http://s019.radikal.ru/i602/1204/1a/8efb3c0eb8de.jpg
The result:
http://s019.radikal.ru/i602/1204/bb/255d64f21b44.jpg

NightFox
05-25-2012, 07:35 AM
Original message (http://forum.ixbt.com/topic.cgi?id=28:27061-28#896) (caution: Russian! :D use google translation (http://translate.google.ru)/translate.ru (http://translate.ru))

More on the topic:
I read that different people may have left half brighter than the right one and otherwise.
The author of this mod (it Yamakasi ES / LM270WQ1 (SD) (B1) without inscription "evalution". Sticker native, not sticked on top) wrote earlier about this (essence):

This is exactly the same case, but I have left half. Corrected by soldering a resistor. This display lights in electronics into 2 groups - left and right, and the channel imbalance at low brightness can be huge. The matrix display 6 groups. The Apple stabilize the 3 channels, but there is a chip aligns very accurately. (free translation)

NightFox
06-09-2012, 04:00 AM
Can anyone has ever seen.
Scheme: http://apt.kimenet.ca:8082/dump/img/Catleap_Q270/catleap_mod.pdf