I got this 47" Seiki for nothing and thought I would give it a shot. It is LED backlight of which will be new to me. Tried to power it up and saw no signs of life.
After opening, capacitors EC1 and ECL1A both being 10uf 400V were vented on the Power Supply board. The board was loaded with CapXons so I recapped entire board. After powering up now, I could make out "SEIKI" logo very faintly and shortly after power supply shuts down. I have found out a few things. I have 5V standby, I get PSon, +5, 12 and 24 volts after switching on and power supply appears to be operating normally for 10 or 15 seconds, then it shuts down. The logo kept getting fainter everytime I turn it on and now I can't see it anymore.
I read some Seiki posts and I don't think the LEDs are the problem, but I don't know. If I measure LED1+ and LED2+ after turning on, I get around 54V for a couple seconds, then jumps up to 120+ VDC for another couple seconds at which time PS shuts down. I unplugged both strings from PS board and I get the same symptoms. That is why I don't believe the LEDs are the problem, but like I said, I am not familiar with their fuction. If there is some open circuit protection, then this would not be a valid test and I could understand the PS shutting down.
I have tried unplugging power feeds to the main board but the 12V cable contains PSon, so can not see who is pulling the PS down. I really wanted to jumper 5V standby to PSon disconnecting everything from PS except the LEDs to see if the PS could light the backlights but I was afraid that might not be wise so here I am. I have enclosed a picture of the general layout and the front and back of the PS. I will remove the other boards and attach photos as needed.
I appreciate any insight and thanks.
After opening, capacitors EC1 and ECL1A both being 10uf 400V were vented on the Power Supply board. The board was loaded with CapXons so I recapped entire board. After powering up now, I could make out "SEIKI" logo very faintly and shortly after power supply shuts down. I have found out a few things. I have 5V standby, I get PSon, +5, 12 and 24 volts after switching on and power supply appears to be operating normally for 10 or 15 seconds, then it shuts down. The logo kept getting fainter everytime I turn it on and now I can't see it anymore.
I read some Seiki posts and I don't think the LEDs are the problem, but I don't know. If I measure LED1+ and LED2+ after turning on, I get around 54V for a couple seconds, then jumps up to 120+ VDC for another couple seconds at which time PS shuts down. I unplugged both strings from PS board and I get the same symptoms. That is why I don't believe the LEDs are the problem, but like I said, I am not familiar with their fuction. If there is some open circuit protection, then this would not be a valid test and I could understand the PS shutting down.
I have tried unplugging power feeds to the main board but the 12V cable contains PSon, so can not see who is pulling the PS down. I really wanted to jumper 5V standby to PSon disconnecting everything from PS except the LEDs to see if the PS could light the backlights but I was afraid that might not be wise so here I am. I have enclosed a picture of the general layout and the front and back of the PS. I will remove the other boards and attach photos as needed.
I appreciate any insight and thanks.
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