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Samsung LE40A536 constantly restarts itself
sparky:
have you checked the switch at the side
dave
Bambooz:
All the buttons check out fine. Both on the little PCB on the side (menu, channel, volume, etc. buttons) as well as the power button in the center. No glitchy-ness whatsoever.
Kinda interesting that this one doesn't have a hardware power switch.
All those button boards are connected via 1 plug to the mainboard.
Can be seen in the video at around 0:25 at the bottom right.
Rightmost connector = speakers, the one to the left of that = all the buttons + IR sensor.
Disconnecting the whole plug has no effect on the problem. Disconnecting the side panel buttons from the power button and IR sensor board (in the center) doesn't help either.
New EEPROMs are on the way. If that doesn't fix it I'm pretty much lost.
I've also tried measuring the output of all the LDOs on the mainboard both while on and in standby, to see if any of them drop down too much. It uses a bunch of 1117's and a few 78Dxx's. All voltages are dead on, except for the two 3.3V ones which sit at 3.28V. Dunno if that's enough for the thing to go berserk, but it shouldn't IMHO as it's still within 1% of the nominal value.
What really confuses me is that the longer i poke aroung on the solder side of the mainboard, the more 2wire serial EEPROMs I find :sign0085:
There's one very close to the CI Slot (the one mentioned in previous posts ; shorting SCL and SDA reset the power on counter to zero), another one close to the side panel HDMI port which i didn't notice before because it was covered in excess flux from the factory (was unreadable), and yet another one close to the LVDS connector to the panel.
Great. Now which one am i supposed to reset/erase or replace..!?
edit: forgot to mention that i know NOT to play with the main firmware EEPROM unless i want to brick it completely ;)
sinclairtv:
This seems amazingly long winded. Change the eeprom first then worry about anything else. 5 gets you 10 that its the eeprom thats the problem.
Bambooz:
--- Quote from: sinclairtv on November 22, 2011,13:13:35 ---This seems amazingly long winded. Change the eeprom first then worry about anything else. 5 gets you 10 that its the eeprom thats the problem.
--- End quote ---
Apparently not.
The EEPROMs arrived after more than a week (from a local seller on ebay). They're new cut-off-tape ST24C256B (marked ST 4256BWP).
Replaced the original with one of the new ones. After plugging it in, only the standby LED is on (doesn't turn on by itself). Trying to power it up with the power button in the front does nothing at all (LED stays solid, no reaction).
When you try it with the remote, the LED turns off (as if it's about to turn on), nothing happens (no backlight, no sound), and it goes back into standby (solid red LED) after ~10-20 seconds.
I've tried it multiple times, and let it sit there for a while just in case it was still doing something (re-writing the EEPROM perhaps).. but no. Same thing.
:(
sparky:
are they soldered the correct way
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