Hi Folks, can anyone tell me if there is much difference between the r2a20299ft and r2a20291ft? Can I use r2a20291ft in place of r2a20299ft? Any info will be much appreciated. Thanks in advance.
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All left and right refers to looking from rear of TV (or looking from front with TV upside down)- TV came with vertical bars and no image. Found faulty TVS on left buffer board. Also replaced T-Con (may have damaged the original while hot air removing components, board has slight warp) and have full image but few horizontal lines on the screen. Some of the lines appears to be 2 pixel tall while others are 1 pixel tall.
- Disconnecting left and right buffer board potentially reveals problems on both sides with different signals (unless this T-Con require jumper like Samsung FB_TRDY1&3) Fault
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Problem
This is an LG edge LED lit LCD Display. The LEDs are on the bottom edge of the display. There are 2 bars (left and right) Each bar has many LEDs and a 6 pin connector. Each pin drive several LEDs thus is the highest current flow / heat junction. The weak lead free solder gradually fails with thermal expansion/contraction cycling and increases resistance. PSU will compensate up to a point, then when the current is too high, PSU just shut down the backlight causing a dark display. I have even seen one which the connector just fell off as solder points became completely detached.... -
- Prior owner tried a replacement main board. No difference.
- Samsung 2x red blinking standby LED = panel fault
- Jumpered FB_TRDY_1 (pin 1 CN1300 left. main tcon->left side buffer boards) and FB_TRDY_3 (pin 95 CN1301 right. main tcon->right side buffer boards) This allows testing individual T-Con (on main board) connection to panel on this Samsung. Found fault on left side (viewing from rear of TV)
- Each side has 2 buffer boards, disconnected left side flex between 2 buffer boards. Fault is on the left most board.
- Tape masking eventually isolated to CN1300 pin 15 (CKV4_GOA) Display
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Hi all,
I'm interested in understanding how a buffer board chip is working. I know there's about 90 outputs per chip to the plasma panel, but I'm more interested to know about the input pins. I guess that some of them are address pins, but I want to know more.
So far I've found nothing at all. I haven't found any datasheet about the various buffer chips, and I haven't found any schematic for the buffer board using them (Y Buffer Board in Samsung's terminology).
Any information will make me happy. It can be from any buffer chip or plasma TV manufacturer.... -
LG42PC3D -UD originally with green lamp but no display or audio.
Owner says was working, then went 'pop'.
All 5V caps bulging. replaced.
All PSU output voltages within spec but -Vy is low on YSUS.
One of three parallel fets between SUS_OUT and SUS_DN is zenering,
eventually shorts DG. Replaced all 3 - -Vy now OK.
Y scan buffer test point does not follow YSUS output below -50V
Note: This unit seems to expect YSUS output to park at -Vy in between
drive signal pattern periods. A replacement drive signal board confirms this....11-18-2021, 11:49 AM
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