I recently started having issues with my Samsung LN52A630M1FXZA - it turns on and shows a very corrupted display, then turns itself off and on again, usually coming up properly on the 2nd or 3rd attempt. Sometimes when the display is corrupted, the speakers screech. After it turns on successfully, I can turn it on and off reliably. The failures usually happen the first time I turn it on each day.
I opened it up and the caps all looked flawless (no bulge, no leakage), but I replaced 6 caps: CM854, CM855, CM856, CM858, CM851, CM852
). I didn't replace CM859 (a 50V 47uF cap).
That didn't reliably solve the problems. The only input to the TV is from a computer via HDMI2. As far as I can tell, if I turn the TV on while the computer is sleeping, it works, but if the computer is driving a signal when the TV turns on, it sometimes doesn't work. I have an antenna, but I haven't tried powering up with the TV looking at the antenna input rather than HDMI2.
I used the "EER Reset" (or something like that) in the service menu to attempt to reset the EEPROM. I haven't shorted any pins on anything because I couldn't identify the right chip.
From reading a few other threads, it sounds like there may be problems with the main board. I've tried cooling off a few components to reproduce the issue (canned air, upside down), but so far I haven't found a reliable way. That said, I'm concerned about being too aggressive with cooling because it's humid here, and it's VERY easy to condense water / ice on components. I don't have a hair dryer to try preheating the board before I turn it on the first time (I have an iron and a blowtorch... but those don't seem ideal). I haven't tried cooling any components on the back of the board. I have a DMM but I don't have easy access to an oscilloscope.
Where should I go from here? It looks like people are selling mainboards for about $110, and I found one place offering repairs for $55, but if I can narrow down the problem to something I can fix myself, I would prefer to do that. Thanks!
edit: at least one component on the mainboard makes some noise, but I'm not sure which. It isn't loud enough that I would've noticed before taking everything apart.
I opened it up and the caps all looked flawless (no bulge, no leakage), but I replaced 6 caps: CM854, CM855, CM856, CM858, CM851, CM852
). I didn't replace CM859 (a 50V 47uF cap).
That didn't reliably solve the problems. The only input to the TV is from a computer via HDMI2. As far as I can tell, if I turn the TV on while the computer is sleeping, it works, but if the computer is driving a signal when the TV turns on, it sometimes doesn't work. I have an antenna, but I haven't tried powering up with the TV looking at the antenna input rather than HDMI2.
I used the "EER Reset" (or something like that) in the service menu to attempt to reset the EEPROM. I haven't shorted any pins on anything because I couldn't identify the right chip.
From reading a few other threads, it sounds like there may be problems with the main board. I've tried cooling off a few components to reproduce the issue (canned air, upside down), but so far I haven't found a reliable way. That said, I'm concerned about being too aggressive with cooling because it's humid here, and it's VERY easy to condense water / ice on components. I don't have a hair dryer to try preheating the board before I turn it on the first time (I have an iron and a blowtorch... but those don't seem ideal). I haven't tried cooling any components on the back of the board. I have a DMM but I don't have easy access to an oscilloscope.
Where should I go from here? It looks like people are selling mainboards for about $110, and I found one place offering repairs for $55, but if I can narrow down the problem to something I can fix myself, I would prefer to do that. Thanks!
edit: at least one component on the mainboard makes some noise, but I'm not sure which. It isn't loud enough that I would've noticed before taking everything apart.
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