Samsung LE46M87BD - main board hdmi question

[tn245]

This TV originally was doing 2-secs to black. Long and fun story which I'll spare you but I've got the backlights working now.

Now it works great on DTV but switching to HDMI does what you can see in the picture. Gradually fades into lots of lines. It also immediately crashes the raspberry pi I have connected as soon as I switch to that input.

I have the TV working, because the backlight fix involved tracking down a cracked panel TV to steal bulbs from and it also had a working main board. But it would be nice to know if this board is trash or repairable anyway.

Pictures of the board attached. Immediately you might notice the resistor that someone has added. What do you think that is doing? I tried testing some regulators but the TV reboots as soon as I touch the middle pin of the first one I got to. Also there are lots on the back side of the board.

Just wondering mainly if someone has seen this before, and if it's worth bothering to go further with.

Thanks!

[johnboy1313]

Re: Samsung LE46M87BD - main board hdmi question

If you have another main to test with, I would swap the good mainboard in and get every voltage reading I could get, then swap the original back in and compare readings.

[tn245]

Re: Samsung LE46M87BD - main board hdmi question

Any ideas where specifically to test voltages?

Here's a pic of the back side of the board btw.

[flocko]

Re: Samsung LE46M87BD - main board hdmi question

That resistor is fitted to all these BN94-01206C boards if you have a spare board with this same part number fit it and see if you get the same. but dont go by the BN41-xxxxas this is the board pattern number Flocko

[tn245]

Re: Samsung LE46M87BD - main board hdmi question

Really? Ok, I assumed it was someone's repair. The spare board I have is a slightly different version. Part no BN94-01490E.

[flocko]

Re: Samsung LE46M87BD - main board hdmi question

BN94-01206C is fitted to the LE46M87 BN94-01490E is fitted to LE46M86 i would check what panels are fitted ? as Samsung were fitting all manor at this time

[tn245]

Re: Samsung LE46M87BD - main board hdmi question

The panel is Samsung LTA460HT-LH2. The spare board came from same model LE46M87 but with AUO T460HW02 V0 panel. Had to change the panel in the service menu but the spare board works fine.

The question is about the old board. What's wrong with the hdmi inputs and is it worth trying to repair or just forget it? I may check the regulators, but as most of them are on the back side and some are under metal covers I'm not that excited about doing it. I have the TV working, but as these boards seem pretty rare and expensive it seems worth at least looking into whether it's fixable. Was hoping someone had seen something like this before.

[tn245]

Re: Samsung LE46M87BD - main board hdmi question

Well I swapped back in the old main for some more testing and lo and behold it decided to work today and has been going all morning. So it's either an intermittent thing or something just wasn't quite sitting right the first time. Will keep testing and see but will be happy if I can sell the other board as it's an expensive one. The only reason I asked really is because of that resistor which made me very suspicious that something had previously been up with the board, but good to know it's fitted as standard. Thanks.