Ian S.
New User
May 5, 2014, 8:18 PM
Post #1 of 8
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Samsung UN46D7000 Turns on and Off Repeditivly.
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I bought a Samsung 46D7000 LCD TV knowing it had this problem and I was hoping it could be fixed, I took a chance.
When the TV is plugged in, it turns on and about 1 second later (just as the Samsung Smart TV lights up on the screen), the TV turns off, then on, and then off. It will do this indefinitely.
The power board is clean, no bad caps as far as I can see, but haven't tested any. No cracked resistors, nothing. I know that to test a capacitor, one pin has to be unsoldered from the PCB and I have been hesitant to do this up until now.
When I disconnect the cable running from the power board to the main board, the on/off cycle stops and there is 1 click and there is power on the P/S board. On the Samsung 7000 series TV's the backlight should illuminate when the power cable is disconnected from the main board, but my backlight does not light up.
I tried the other method of turning on the backlight by jumping A5V to P_DIM 1-4 and nothing.
I connected the negative lead of my multi-meter to the TV chassis and the positive to the terminals on the power connector going to the main board. I checked each pin and all the voltages seem normal.
1. OD_LEVEL - 5.3V
3. OD_ON/OFF - 5.09V
5. GND
7. B13V - 13.86V - With the screen connectors connected, the voltage is 13.74V
9. B13V - 13.86V - With the screen connectors connected, the voltage is 13.74V
11. V amp - 13.86V - With the screen connectors connected, the voltage is 13.74V
13. V amp - 13.86V - With the screen connectors connected, the voltage is 13.74V
15. GND
17. B5V - 5.39V
19. B5V - 5.39V
2. P-DIM4 -
4. P-DIM3 -
6. P-DIM2 -
8. P-DIM1 -
10. B13V - 13.87V
12. BLU ON/OFF - 4.74V
14. GND
16. GND
18. A5V - 5.39V
20. POWER ON/OFF - 3.37V
I got the TV to work, but only for a minute or so.
I took off the cable from the power board to the main board and took wires 1-10 out of the connector. I put back in 3 wires twice (nothing working, but no clicking either) then I started 1 at a time.
When I got to wire 7, the TV started to act normal (no clicking, normal on/off button) with sound, but no picture. I plugged in wire 9 and the picture came on. The only wire not connected was wire 10 (B13V). The TV worked for about a minute and then started the on off cycle again.
I bought a used power supply (BN44-00427B) that I was assured works perfectly (taken out of a TV with a cracked screen) and the TV does the same thing. This time though, without the cable connected to the main board, the backlight does light up but the TV still clicks on and off. With the old power supply, and with the cable disconnected from the main board the TV did not click on and off but the backlight never came on.
But this new used P/S clicks on and off when just the 110V power cord is connected. I called the guy I got the board from and he is saying the main board in bad and overloaded the P/S he sold me.
Anyway, I went to the Samsung repair center and they want $150 just to look at the TV, so to hell with them.
I know this is a long post, but I wanted to give as much info as possible.
Any help in diagnosing the problem would be fantastic. I am giving this another week and if I can't figure it out, I'm going to buy a p/s and a main board, let's hope it doesn't come to this.
Thanks,
Ian
(This post was edited by Ian S. on May 5, 2014, 8:25 PM)
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