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Aric, Technician
Category: TV
Satisfied Customers: 44905
Experience:  15+ years in the field. Owner of AV Installation, OEM and Repair company
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We have a projection older Mitsu large HD TV. Comcast was

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We have a projection older Mitsu large HD TV. Comcast was kind enough to discontinue our service. When they turned it back on this week, all we can see on the TV screen is static. None of the buttons work on the front of the TV, and the TV Timer button blinks and then turns off the TV after awhile. Is there any hope for the TV, or is it junk?
Hello there and welcome to Just Answer. My name is XXXXX XXXXX I will be assisting you today. I am an engineer with over 30 years of electrical and electronic training, repair and installation experience. I will try and answer your question accurately and precisely so that we can get you on your way.

Now..Ok. Power the TV up and let it switch itself off as it has been doing.

ON THE TV, press the MENU and INPUT buttons together for 5-8 seconds. If you don't have these buttons, press ACTIVITY and the Channel Down button. On some sets the INPUT button is labeled DEVICE.

The status LED will then flash indicating a two digit code separated by a brief pause.

It could be three flashes and then two flashes which would be 32.

The sequence will repeat 5 times.

Can you tell me the code please?

Remember, you can only do this AFTER the TV has shut itself down.

Please let me know so that we can continue.

Customer: replied 4 years ago.

Currently I have the TV in the "net command" mode and because it started memorizing first the analog channels, and now is counting up and memorizing the digital channels, and cannot try what you are suggesting. If possible, I will try your suggestion once this process has stopped.

Thanks, Jim

JIm, if you are Net Command mode then the TV is working is it not?

Assuming that it shuts off, run that procedure. It will (hopefully) tell us what is going on.

Customer: replied 4 years ago.



The TV shut itself off and I tried what you said. The code is "12."


Please advise.

Ok, so the TV is shutting off not because it is faulty but because it sees no signal. This is simply to save the color guns which have a finite life.

Tell me what you have plugged into it and how.

Then we can continue.

Customer: replied 4 years ago.

The TV is plugged into a power source of course.


The cable goes from outside to my cable box.


I have an HD wire going from back of cable box to the HDMI 1 source back of TV


I have an audio wire going from the TV to a Home Theatre Receiver.


Nothing else is plugged into the TV.


I have a PA PR150BNM cable box from Xfinity. By the way I plugged the cable box into a different TV last night and the picture worked immediately.

Ok so using the INPUT button on the Mitsubishi remote, select HDMI1.

Please let me know what happens so that we can continue.

Customer: replied 4 years ago.

I do not have an input button, I have a device button. Normally this is how we switch from TV, to DVD, for example. Right now sometimes I see "antenna" come up on the TV in the upper left screen. When I hit device, nothing happens, either from the remote, or from the TV. None of the buttons on the TV respond except for what you told me to do to get the "12" code.

Customer: replied 4 years ago.
Relist: Incomplete answer.
Steve had me on the path to fixing the problem, but then went offline. Not sure why?? I hope I do not have to start over. I hope that my issue and where we are at was stored.
Do not select Antenna as this is not the correct setting for the TV to be set for "Device". Instead what you want to do is keep pressing Device until you have the TV set to the HDMI Input that you're plugged into. Please try that and let me know what happens. Again, do not select Antenna, select HDMI.
Customer: replied 4 years ago.



I understand that I want to use the Device button to get to HDMI. Currently both the Device button on the remote, and on the TV do not respond. I cannot see the device area that I have seen in the past.


If it helps, Steve, the previous tech had me hold two buttons and the "code" that resulted was 12. Maybe 12 means something to you. He said that the TV is not getting a signal which is why it keeps shutting itself off.


I know the cable box works because I tried a different TV last night with it and it worked perfectly.

The code 1-2 indicates "No Fault" per Mitsubishi's fault code.

The TV will shut itself if if does not sense a signal- only meaning that it was set to the Antenna setting and you were using HDMI, so the set shut off when it did not sense an antenna.

What exactly show up on the TV screen right now if you power the set up?
Customer: replied 4 years ago.

All I see when TV is powered is static.

Okay then if you go to the set and press Device, Menu, or Volume what happens?
Customer: replied 4 years ago.

Both on the TV, and/or on the remote none of the usual buttons work. The only thing I have been able to see is the "Net Command" area where different things can be programmed. Then the picture looks normal with a blue screen background. Once that is gone, back to static without buttons working.


The TV is older, but when working has a great picture. Not sure if it would be worth it to hire someone to look at it, and it weighs a lot, so difficult to move.


Okay unplug your TV, then press and hold the power button on the set for 15 seconds and release. Then plug the set back in and turn it on. Let me know if the Device button on the set will then allow you to change the Input to HDMI.
Customer: replied 4 years ago.

Ok. I followed your steps. When I plugged the TV back in the timer button was blinking. I waited for the green light to stop blinking, then turned on the TV. I still see static, and none of the buttons on the TV, including the Device button do anything.

Unfortunately, the Mainboard, or the Power Supply output to the Mainboard on your set has failed. They work in tandem to allow the set to turn on, the Power Supply provides the voltages to various circuits in the TV, and the Mainboard contains much of the communication required for the Power Supply to turn on.



The power supply is the board that the AC cord connects to inside the TV. Often times, one or more capacitors on this board fail, and will give you these symptoms.




The Mainboard is the board directly mounted to the rear panel of the set, that routes and processes all of the AV signals to the TV. This is a common mode of failure for these sets. Average cost or this type of repair is around $350 parts and labor. There is no reset or series of buttons you can press to fix this problem, and the set will require service. I would personally consider carefully whether or not to put that kind of money into this set, as a new TV can be had for around the same cost as repairing this one.

However, if you'd like you can use the link below to locate a tech in your area:


If you need further assistance let me know and please do not forget to rate my service before logging off.

Customer: replied 4 years ago.

How certain are you that I need a mainboard? Could I purchase a main board and install it myself, or would that be dangerous? I would agree that the cost would not make sense if that is the problem.


It seems odd that Comcast shut off our service because of a misunderstanding. When they turned it back on the TV worked for 1 day, yesterday, and then last night all I could get is the static I have been reporting.


If you are pretty certain, that this is my problem, I will probably purchase a new TV. If a tech determines that a few more simple fixes could solve my problem, I would love to not replace the TV.


How much do I pay for your answer?


Thanks, Jim

As stated, the problem is EITHER the Mainboard, or the power supply.

Mainboard houses the AV, and Tuner connections and the EEPROM (processor), that allows the set to bootup.

Power Supply takes AC and rectifies into various DC voltages. The blinking light typically is caused by one or more faulty capacitors in the power supply, or the EEPROM not booting.

That said there is NO way to know for sure without having the set diagnoses in person by a tech with a service manual. We can only narrow it down so far online.

One last thing to check, is a button that reboots the EEPROM on your set that is called "AV reset". Check the front of your set for this button, then press and hold it for 8 seconds and release.

If this works, then we got lucky. If not, then I would personally put the money into replacement of the TV as this would be the last user reset you could perform.
Customer: replied 4 years ago.

OK, a question because I have already tried the reset button. You said the Mainboard is about $300 parts and labor. If the problem is the power supply as opposed to the main board, is that any cheaper?

No unfortunately the cost is about the same. Most of the labor is using a meter and the service manual to test and isolate which board is causing the issue. Additionally I realize the problem surfaced not long after the cable was restored, but its unrelated because the cable has absolutely no effect on the TV's buttons. They supersede any external connections, signals, etc.
Aric, Technician
Category: TV
Satisfied Customers: 44905
Experience: 15+ years in the field. Owner of AV Installation, OEM and Repair company
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