Magnavox 42MF230A/37 HDTV Random Turn On

[herb97]

I've had this unit for approximately 5 years with zero problems. For the past 3 days it has begun to randomly turn itself on. Also the AV identifier will now occasionally pop up on the screen when in full operation.

I am just a frustrated viewer, not particularly technically astute. My attempts to fix ended after unplugging, letting it sit, and plugging it back in to the power source. Not surprisingly this proved ineffective.

Any help would be appreciated.

[retiredcaps]

Re: Magnavox 42MF230A/37 HDTV Random Turn On

For the past 3 days it has begun to randomly turn itself on.

Odd, we usually get people saying the TV turns itself randomly off, not on.

[tom66]

Re: Magnavox 42MF230A/37 HDTV Random Turn On

Two potential issues:
- Maybe standby rails are dropping out and resetting (for an unknown reason) causing the TV to turn on?
- Maybe the side button board has dirt in it or a loose connector; this also explains the AV identifier (which might be triggered by a button.)

Both problems will require you to open up your set and take pictures.

[PlainBill]

Re: Magnavox 42MF230A/37 HDTV Random Turn On

Tom66 has identified one of several potential areas that could be causing the problem. The 'control panel' is one. Another is the remote sensor sending spurious signals to the standby processor - either generated internally or from another remote. (Recall the scene from 'Grumpy Old Men' with the TV remotes). Another possibility is a problem with the standby processor, but that seems unlikely.

I'd suggest opening the TV up and disconnecting the cable to the control panel. If it then works properly, you know the cause, and you can often pick them up inexpensively.

PlainBill

[splatee]

Re: Magnavox 42MF230A/37 HDTV Random Turn On

First off sorry to bring an old thread back but I still can not seem to start a new one even after a few posts and figure this is related to my issue.

I picked up a magnavox plasma 42mf230a for free that randomly turns on by itself and off and then would just powers cycle and makes a click sound when powering on and off. The image looks great when it works.

I downloaded the service manual and checked voltages coming from the power supply and hey all seem to be within spec. I checked e power supply board for bulging caps and did not see any but went ahead and resoldered them in case of a cold solder joint. I also unplugged the "Y" board and "X" board and tv would still power up and down on its own. I even went as far as to unsolder the rfi sensor for the remote to make sure it was not picking up something. He tv did not come with a remote either so I can not go into the service menu.

Any other ideas? I'm pretty sure it is probably a cap issue on the power supply but don't want to randomly change them, there are a lot of them. On a side note all the boards and panel are labeled Samsung.

One other thing I have not looked at is the PDC board aka power down control board, wonder if that may be an issue?

Thank you