Can anyone upload a pic of the Atmel 24c256 chip? I cannot find it to save my life! Thanx!
Here it is on my LNS4051D, with wires soldered on pins 5 and 6.
In case the photo goes away one day, it is an 8-pin chip labeled IC203, slightly to the left and below the center of the Main board. An arrow (triangle) on the board points to pin #1, which is in the lower right corner of the chip. Pin #5 is in the upper left corner, with #6 right below that. (all of this while looking at the board when installed in the TV in the correct orientation.) Following the advice of another member, and (correctly!) figuring it would not work on the first try and I'd be doing it multiple times, I carefully soldered wires to each of these pins so I could do the shorting more precisely.
I believe this same board (but with different EEPROM parameters) exists on the LNS2651D, LNS2652D, LNS3251D, LNS3252D, LNS4051D, and LNS4052D. I looked at photos, and other than an extra connector for external connection, the Main board on these TVs appears to be the same as for the LNS2641D (and probably others in the ...41D series).
BUT - this did not yet work for me, so it could be wrong. When I plug in the TV with pins 5+6 shorted, it clicks only once and does not cycle. That suggests that I've found the right IC and shorted the right pins.
But pressing the buttons on the remote (Mute, 1, 8, 2, Power) that are supposed to turn it on in Service mode do nothing at all.
If anyone who has done this successfully knows what I might be doing wrong, please let me know. Otherwise I'll be ordering a new Main board soon.
UPDATE - I have the service manual for this exact TV, tried every permutation on remote-button sequence I could think of, etc. and nothing worked. I ended up replacing the main board, which successfully stopped the power cycling, but it just turned the screen white. I then replaced the T-con board as well, which has it all fixed now. I then put the original (bad) main board back in to see if it might work with the good T-con board. It did not - was the same as before. I tried shorting the EEPROM, etc. and it still did not work. From having traced the voltages through the main board, I am convinced that it is just a firmware issue and can probably be reset somehow, but I cannot do it.