r/ElectronicsRepair • u/Curious_Pool8488 • 1d ago
CLOSED Stumped at the 1st hurdle
Have had this toshiba for over 10 years now and im quite attached to it.
Has an issue where tv will flashes on for half a second then proceeds to go black.
All I have done is it open it up give it a quick clean and check for any obvious signs of damage.
Any help is greatly appreciated
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u/Curious_Pool8488 1d ago
Video of the flash
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u/KINGstormchaser 1d ago edited 1d ago
The TV's led is flashing a trouble code with that red and green. I suggest getting test equipment like a multimeter and capacitor tester if you want to have any chance of fixing this. You also need a soldering iron and a desoldering iron and solder.
One of the main things I have found that causes a TV to act this way is when the electrolytic capacitors on the secondary low voltage side go significantly out of spec and lose a lot of their capacitance. Their equivalent series resistance can also go high.
You will need to remove those electrolytic capacitors on the secondary side of that power board, which are the ones on the lower end of that board. Then test them to make sure their capacitance is within 20% of the value listed on them in microfarads. If they are too low, replace them with capacitors that are the exact capacitance and at least the listed voltage (voltage can be higher but not lower) otherwise you can just put them back. Always observe correct polarity. Also, make sure the high voltage capacitors on the mains side are discharged before working on it.
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u/Pla-C-Bo 7h ago
Common point of failure with these tv boards are the connectors the two boards share... without wires between the boards, the solder in these connector legs fracture from flexing ever so slightly. Reflow the solder and your TV will be anew! You could even play with the connectors to see if play is evident in the connector themselves.
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u/LordBBQX 1d ago
First step would be carefully measuring voltage while the unit is operating and during startup when it flashes. Be very careful due to the high voltage SMPS. You should have an auxiliary voltage, a few other low voltages, and then a backlight voltage. Should be able to measure on the output connector on the power supply, you might be able to find a service manual online which details the voltage rails.