Sharp LC-46LX830H Power cycling

[Bolt Upright]

Hi there,

First real post for me. The other day my Sharp TV started power cycling on and off every 2 minutes. It started up as per normal but then an audible 'click' was heard, perhaps a protection relay, and it completely shut down. After a couple of minutes the tv turned back on to where it was when it shut down.

This cycling continued until I decided to shut it down and take the back off. I let everything cool down and tried again and the same thing happened. I can't see any damaged caps but I did notice one of the heat sinks was very warm to the touch after only a couple of minutes. My problem at the moment is that I only have an analogue multimeter so it is very difficult to get accurate voltage readings. I shall be buying one very soon!

Any thoughts about the quick warming heat sink?

[nomoresonys]

Re: Sharp LC-46LX830H Power cycling

Flip it over and inspect all your solder joints.

[Bolt Upright]

Re: Sharp LC-46LX830H Power cycling

After a thorough inspection, I can't see any problems with the soldering.

Any other suggestions would be most appreciated.

[nomoresonys]

Re: Sharp LC-46LX830H Power cycling

Try unhook cable from power board to mainboard, plug power back into powerboard see if it quits cycling.

[Bolt Upright]

Re: Sharp LC-46LX830H Power cycling

Yep tried that, still no luck.

[nomoresonys]

Re: Sharp LC-46LX830H Power cycling

Ok, did you try it with everything unplugged from powerboard, plug power cord in to powerboard and still cycling?

[dick_barton]

Re: Sharp LC-46LX830H Power cycling

If you can get it to switch on can you turn the backlight (not brightness) down as much as possible and see if the time to shutdown increases.

[Bolt Upright]

Re: Sharp LC-46LX830H Power cycling

Hello again, here I am several months later giving this tv repair another go.

A couple of things,
I how have a digital multimeter which will help immensely.
I have noticed that the tv cycles on and off when in standby mode. ie. the red light comes on and then about 30 seconds later is goes off. The relay clicks and the process continues.