Hey everyone,
I was given a Sanyo DP5749 Plasma that has failed. The symptom is the TV tries to start up and shuts back off about 3 seconds later. With the service manual I was able to determine that the TV is shutting down due to detecting a missing power rail. The 5V supply to the logic board is okay at startup but after a second it disappears. The TV shuts off shortly afterwards.
I traced the problem to a 3.3V enable signal from the D board to the power supply. This signal disappears for some reason which shuts a few power rails on the PSU off. The signal comes from a custom Panasonic chip on the D board so I am unable to trace it further than that.
According to other threads on here about this model, it appears a common problem with this TV is a NAND flash chip on the main board getting corrupted. The service manual also verifies that this is a known problem. However, the symptom that is listed is power cycling of the TV with a 15 second or so delay. This is not the symptom I have as the TV shuts down after 3 seconds and does not try powering up again until you push the power button.
Before I pay some guy on eBay $40 for a flash chip which hopefully has the correct firmware on it, I would like to be sure this is in fact the problem.
Does anyone have any input?
I was given a Sanyo DP5749 Plasma that has failed. The symptom is the TV tries to start up and shuts back off about 3 seconds later. With the service manual I was able to determine that the TV is shutting down due to detecting a missing power rail. The 5V supply to the logic board is okay at startup but after a second it disappears. The TV shuts off shortly afterwards.
I traced the problem to a 3.3V enable signal from the D board to the power supply. This signal disappears for some reason which shuts a few power rails on the PSU off. The signal comes from a custom Panasonic chip on the D board so I am unable to trace it further than that.
According to other threads on here about this model, it appears a common problem with this TV is a NAND flash chip on the main board getting corrupted. The service manual also verifies that this is a known problem. However, the symptom that is listed is power cycling of the TV with a 15 second or so delay. This is not the symptom I have as the TV shuts down after 3 seconds and does not try powering up again until you push the power button.
Before I pay some guy on eBay $40 for a flash chip which hopefully has the correct firmware on it, I would like to be sure this is in fact the problem.
Does anyone have any input?
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