Magnavox 42MF438B/F7 power light blinks for several minutes then goes solid but still no pic. cannot power box off with remote or power button on tv

Anon, try re programming/setting it up, if that does not work look for a compatible remote.
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THIS IS NOT A POWER SUPPLY ISSUE PLEASE REPLACE MAIN BOARD THEN YOUR PROBLEM WILL BE SOLVED .
THANKS

Join Date: Nov 2011 I have a Philips 47PFL3603D/F7 with the same problem. It was the IR sensor board causing the problem. You can search online to find the board, which almost everyone will most likely not have in stock, and cant be ordered. The part you need is this: 313926859181 IR Remote Sensor.

Models it will fit are as follows: Substitute Parts 313926859182
Known Models
MAGNAVOX 42MF438B/27
MAGNAVOX 42MF438B/27
MAGNAVOX 42MF438B/F7
MAGNAVOX 52MF438B/27
MAGNAVOX 52MF438B/F7
PHILIPS 32PFL3403D/85
PHILIPS 42PFL3403D/27
PHILIPS 42PFL3403D/F7
PHILIPS 42PFL3603D/27
PHILIPS 42PFL3603D/F7
PHILIPS 47PFL3603D/27
PHILIPS 47PFL3603D/F7
PHILIPS 52PFL3603D/27
PHILIPS 52PFL3603D/F7

If you can find the board, great! A replacement board costs about $12.00. If you can't... we'll there is something you can try ; )

Either way, if you know it's the board, what's the harm in trying?

Remove the back from the TV. You can actually leave it on your stand to do this if you can spin it around to gain access to the back of it. Be sure to unplug everything first!!!

Looking at the back of the tv, the board will be located in the lower left side by the speaker. It will have 2 cables attached to it. Remove them, and take out the screw or two that holds it in place. There will be a plastic tab that keeps it in place also.

Take your fingernail and bend the tab back, and the board should come free. After that you should be holding the board in your hands. The side of the board with the connectors on it is the side you want to manipulate. There will be a tiny surface mounted capacitor beside one of the wire connection sockets. Take a utility knife and scrape it off/ you could use a soldering iron but it should come off very easy with a knife.

Plug it back in, and give it a try! If it works... great! If not, find a replacement board, and try that.

Hope it helps someone!!!!

If you take back off you should see a problem with the power supply board, caps bulging outward could be 1500uf or 2200uf

Your television is in need of repair. Hard to tell what exactly needs to be repaired but when the power light blinks in that way then this is the TV's way to tell you it needs to be serviced.

that set is highly rated by users .. it first came out in early 2009 (i think) so you might check to see if any warranty remains ... the display is illuminated by several lamps .. each lamp has its own high voltage inverter .. all the innverters are powered by an output of the low voltage power supply (often 18 volts)... i would suspect a problem with that low voltage power supply.. either a bad capacitor or a thermal issue .. .. ..

Not good. Make sure you have not blocked cooling to TV. It need s air flow. sounds like overheating

I have exactly the same problem with a Magnavox LCD 42", very similar model 42MF437B/37. I don't have a solution. If you unplug the TV and plug it back it starts working, sometimes for hours, sometimes for less than 5 minutes, before it turns off again. Does anyone have any real solution?

Mine was doing the same thing. Update the firmware and it fixes the problem. Updating the firmware is done by downloading the file to a thumb-drive from the phillips product support page then plugging in the drive into the side of your television and turning it on. See your manual for slightly better instructions.