How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Aric Your Own Question
Aric, Technician
Category: TV
Satisfied Customers: 41220
Experience:  15+ years in the field. Owner of AV Installation, OEM and Repair company
Type Your TV Question Here...
Aric is online now
A new question is answered every 9 seconds

I have a 40" Coby flat panel tv that wont turn on.

This answer was rated:

I have a 40" Coby flat panel tv that won't turn on.

How long have you had the set for and when did the problem occur?

Was it after a storm or power outage?

Are there any signs of life at all on the TV (Power light blinking, steady, click sound when power is pressed, etc.)?

Customer: replied 4 years ago.
Answers to your questions:
1. The TV was purchased in February of 2012.
2. No
3. The power light indicator is on and it will dim when trying to turn the unit on, but after about 5 seconds it returns to full brightness again.

Please disconnect the set from AC power, then press and hold the power button on the TV itself (not the remote), for 10 seconds. After another minute, plug the set back in and press power once. Do you still have the same problem?

Customer: replied 4 years ago.

short inside the set stopping it from fully powering up.

It is most probable that there is a failure on the power supply board inside the TV. Commonly the capacitors on this board will receive a surge and then fail. They can sometimes be visually verified by removing the rear of the set and inspecting them for bulges or leaking fluid at the top or the base of the caps. This is the most common mode of failure for these sets.

Seeing as you are barely into owning the set, you should contact the retailer and you will need to ask them where the closest service location is to have the TV repaired. I wish I had better news, but there are no buttons you can press to fix this and the TV will require service at this stage. If you need further assistance, let me know.

Customer: replied 4 years ago.
Since this tv is beyond the manuf. warranty period. Could I replace the power supply board if there is no visual evidence of damage to the capacitors?
You said the TV was purchased in February of 2012 correct? Do you not have a one year warranty with the set, or was it a refurb?
Customer: replied 4 years ago.
refub only 90 days

That makes sense.

The only power supply for this TV that I could locate, is a refurbished unit as well for sale at the link below:

Customer: replied 4 years ago.
Thanks for the part lead.

These parts are a "no refund" purchase. I'm not questioning your advise, but what is your confidence level this would fix the problem? Is it a $60 gamble?
I am 99% sure, but if you want to be 100% sure, then you will need to be able to use a meter to measure the voltages coming out of the power supply board. If you require further assistance, please let me know.
Customer: replied 4 years ago.
Ok, if you can tell me what points to check I have a meter.

I have digital pics of the power supply and it looks just like the one you referred to from e-bay.

The first thing you'd want to check is the caps on the power board for bulges or leaking. Any of these needs to be replaced. The Power Supply Board is the one inside the TV that the power cable directly attaches to. Any capacitors on this board that are bulged, or leaking a brownish fluid around them are faulty and could cause the problem you're having.

Please only proceed if you have experience measuring live voltages on a circuit board level.

Next, use a DMM set to DC volts, find a common ground on the power supply and probe all of the Outputs for voltage (correct voltages will be stamped on the power supply at the outputs). Do this with NOTHING connected to the Power supply but AC power, and the small board that has the Power Switch. Turn the power switch on, and then measure the voltages on the Power Supply. If a voltage is missing/ fluctuating, then the power board needs to be replaced.

If the power supply outputs its rated voltages, then connect the other boards one at a time until one causes it to shut down. This board would have the short causing the supply to SOS, and would need to be replaced.

A good source to locate replacement boards is and

Customer: replied 4 years ago.
Ok, I will proceed as directed above.

However, I'm in the eastern time zone, so it maybe tomorrow before I can respond back to you...or are you finished with your advice?

Do I need to accept your answer so you can be paid now? And if I needed to ask you something else concerning this issue are you still available after paying you? How does that work?

I'm in the Eastern Time zone as well, but will be logging off for the night soon. The steps above I gave should be all you need to isolate the problem down to the power supply or another component. If you do need further assistance though, this dialogue will remain open and you can still reply back with questions pertaining to this perticular problem. To do that, you simply need to log onto and then click on "My Questions".
Aric, Technician
Category: TV
Satisfied Customers: 41220
Experience: 15+ years in the field. Owner of AV Installation, OEM and Repair company
Aric and 4 other TV Specialists are ready to help you
Customer: replied 4 years ago.
Here are my findings:

The power supply(PS) board is connected through a wiring harness to the main board(MB) where the a/v inputs and outputs are located. The TV power on switch is 24 volts that is connected through the MB. I was able to isolate the back light(inverter) board only. Does that make sense?

The results were as follows; with AC to the "HOT" side of the PS board I measured the rated voltages on the "COLD" side of the PS board. All voltages are all correct when you initially power on the TV switch, but after a few seconds the power drops out on all outputs of the PS board.

Do all of the outputs drop even with no other boards connected to the power supply board?

Customer: replied 4 years ago.
As I tried to indicate above, (which maybe confusing the way I wrote it), the only circuit board I can isolate is the inverter board. The PS and MB boards have to be connected together in order for the TV power switch to work.
Gotcha. I would replace the supply.
Customer: replied 4 years ago.
You're welcome.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

  • I'm screaming your praises!! WOW! I plugged my TV in and bammo! The picture came on bright and beautiful. What a relief! YOU saved me some money and headache. VM United States
< Previous | Next >
  • I'm screaming your praises!! WOW! I plugged my TV in and bammo! The picture came on bright and beautiful. What a relief! YOU saved me some money and headache. VM United States
  • I love this site! $9 instead of a repairman or new/used frig can't be beaten. This older woman will worry less now that she knows about this site. Bless you all. Windy USA
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY

Meet The Experts:

  • Louie



    Satisfied Customers:

    25+ yrs. experience in the field and 5+ yrs. online, down to component level.
< Last | Next >
  • Louie's Avatar



    Satisfied Customers:

    25+ yrs. experience in the field and 5+ yrs. online, down to component level.
  • Rod's Avatar


    TV & Communications Sys Repair

    Satisfied Customers:

    FCC Commercial License, Previous owner of Electronics Repair shop, 40+ years in electronic systems.
  • Pete's Avatar


    Electronic Engineer

    Satisfied Customers:

    Over 16 years of experience installing and repairing electronics.
  • Steven's Avatar



    Satisfied Customers:

    Ma. Master Technician Lic. Authorized Warranty Support.
  • euro-pro llc's Avatar

    euro-pro llc


    Satisfied Customers:

    20 years in TV repair,certified by all major brands- Sony,Samsung, LG,Toshiba, Panasonic, RCA,
  • Daniel's Avatar


    Electrical Engineer

    Satisfied Customers:

    BSEE (Electrical Engineer), 10+ years electronic design experience ,chip, board, component expert
  • Conrad's Avatar



    Satisfied Customers:

    Training on many types of consumer electronics, training on Sony Samsung and JVC