Toshiba 55ul610u blinking blue power light

[KevinCro]

I have a toshiba 55ul610u that has only flashes the blue power light. I got a service manual but it was very brief. The service manual says that a blue flashing light means the cooling fan is not working. However, the cooling fan is working upon visual inspection. I have pulled the main board and the tcon board where the fan is located. There are no bad caps or burnt components of any kind. Any help is appreciated. I have searched the net and haven't found this problem described anywhere else.

[ReeceyBurger123]

Re: Toshiba 55ul610u blinking blue power light

How many pins/wires does the fan have (red, black, yellow ?) I have seen fans where the RPM tachometer fails which basically feeds back to the mainboard to tell it that the fan is spinning ?

[KevinCro]

Re: Toshiba 55ul610u blinking blue power light

I'll check after work. That's a good theory. Hope it works out.

[ReeceyBurger123]

Re: Toshiba 55ul610u blinking blue power light

Ok mate

[KevinCro]

Re: Toshiba 55ul610u blinking blue power light

I checked the fan and there are three wires going to it. A black Blue and Red. I'm guessing the blue wire is the tach? I'll post a pic in a few minutes.

[KevinCro]

Re: Toshiba 55ul610u blinking blue power light

Here is the whole board. Any guess why all those thermal pads are stacked up in there like that. That's the way it was when I first pulled the cover off.

[budm]

Re: Toshiba 55ul610u blinking blue power light

What is fan make and model number?

[KevinCro]

Re: Toshiba 55ul610u blinking blue power light

Made by delta electronics model #KSB0412LB

[budm]

Re: Toshiba 55ul610u blinking blue power light

The Blue wire may be for the ROTOR LOCKED error signal line, check the DCV between GND and Blue wire when the fan is running, then try stopping the fan to see if the DCV on the blue wire changes state. I cannot find the spec of the FAN so I do not know if HIGH on blue wire is normal or LOW is normal, but that does not matter because it should change state when fan is forced to stop.

[KevinCro]

Re: Toshiba 55ul610u blinking blue power light

With the fan running I get 45.5 volts. With it stopped I get anywhere from 2 to 3 volts.

[KevinCro]

Re: Toshiba 55ul610u blinking blue power light

I am getting the 5v standby and then the power tv goes high when I turn the set on. It seems that the tv is turning on. The cooling fan on the tcon runs. The backlight isn't turning on but I couldn't see an image on the screen with a flashlight. I'm willing to take a shot in the dark and replace a board. Any suggestions on which board is most likely the culprit? The blinking led is supposed to be a fan problem. So I'm guessing either a signal is not being sent to the main board to tell it the fan is running or the main board isn't properly receiving it. Thoughts?