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Ask Louie Your Own Question
Louie
Louie, Technician
Category: TV
Satisfied Customers: 12459
Experience:  25+ yrs. experience in the field and 5+ yrs. online, down to component level.
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I have a model M420Sl and the screen is black but has audio.

Customer Question

i have a model M420Sl and the screen is black but has audio.
JA: What's the model number of your TV? How old is it?
Customer: M420SL about 4 years old
JA: Does the TV menu work? Do you have the same problem on all sources/inputs?
Customer: can not get to menu
JA: How long has this been an issue? What happened right before this popped up?
Customer: this happen once before and when i powered up in AM. Turned it off and worked next time I turned on. Turned on this AM and audio work but screen was black
JA: Anything else you want the tv expert to know before I connect you?
Customer: no
Submitted: 9 months ago.
Category: TV
Expert:  Louie replied 9 months ago.

Hi and welcome to the site, I’m Louie. Sorry you had to wait awhile but I’ll do my best to help.

Initially, consider an experiment (if have not been done). Power on the TV and set to a program/channel. If at all possible, darken the room where the TV is. Wait for about 5 minutes or more. Shine a flashlight at an angle (not directly) and nearly but not touching the screen where the volume level / menu display is usually seen.

Press the VOL UP/DOWN or MENU button and note if a dark/ghostly image of the volume level or MENU could be seen.

Postback results.

The above is a test to determine if it is a backlighting issue.

Customer: replied 9 months ago.
I have it on CBS and I can see the CBS logo
Expert:  Louie replied 9 months ago.

...dark/ghostly image of the "...CBS logo..." ?

Customer: replied 9 months ago.
Expert:  Louie replied 9 months ago.

Unfortunately, the described symptom almost always would be indicative of an internal hardware issue.

Are you then considering a DIY (do-it-yourself) repair approach? If yes, access to and familiarity with a multi-meter may be needed.

Customer: replied 9 months ago.
No
Customer: replied 9 months ago.
Any way I can get to the menu to check the input source
Expert:  Louie replied 9 months ago.

Would information / contact details of an independent TV repair shop serve your need then?

Expert:  Louie replied 9 months ago.

On "...Any way I can get to the menu to check the input source...", there would be a MENU button on the side panel of the TV as well as INPUT button. The challenge would be viewing these as the screen would be dark.

If considering accredited / independent TV repair shops, please click HERE.

Select your state or better yet key in your Zip Code and then click on the Submit button.

I realize that the above information may perhaps be not what was expected. Unfortunately, there is no quick-n-easy fix and neither is there a workaround; sorry for having to be the bearer of bad news.

Customer: replied 9 months ago.
I left the TV on this AM to do a procedure at the hospital! When I returned at 3:30 the set was working!!! Not a back light problem??
Expert:  Louie replied 9 months ago.

Could still be.....or likely a cold solder / loose connection with the backlight/inverter circuit.

...or now even the power supply that powers the inverter.