TV sometimes doesn’t power on.

[Sross002]

Hello, I have a Hitachi 42 inch plasmas, model number: HD42S69. The TV sometimes doesn't power on. I have been unplugging it from the wall outlet for long period's of time. After letting the TV sit unplugged, I plug it back in and it works. I don't know what the problem could be or what this issue is an indicator for. Can someone suggest a fix for this problem and explain to me what is going on with it?

Thanks,
Steve R

[Unspun01]

Re: TV sometimes doesn't power on.

With the back of the TV removed, please upload clear photos of the ENTIRE back of the TV, and then close up photos of each board by themselves.

Please ensure your photos are well lit, and not taken with a lousy cell phone camera.

The first step in helping you is helping us see what you see.

[Sross002]

Re: TV sometimes doesn't power on.

Here is a picture...

[Unspun01]

Re: TV sometimes doesn't power on.

Thank you for that photo, but can you also please add additional close-up photos of each of the boards so we can see the components and the part numbers on the boards?

Do you have a Power LED? When the TV does not start, do you see any blink codes from the LED? If the LED blinks, count the number of blinks before the LED pauses and restarts.

Just a guess, but your fans are quite dusty. Your TV may throw an error if the fans do not spin up to suitable RPM fast enough.

Try cleaning the dust from the fans with compressed air and gentle brushing to remove the dust and try again.

See if the fans spin freely, or if they are stuck.

Report back with information and photos.

[R_J]

Re: TV sometimes doesn't power on.

Those are not his pictures.
If your going to use the pictures from another thread, then do what they did to do your repair

[Sross002]

Re: TV sometimes doesn't power on.

That is my picture.

[R_J]

Re: TV sometimes doesn't power on.

My mistake, I saw the picture but did'nt look that close at the name, The picture is too out of focus to to see any problem.
Have you checked the power supply voltages like the standby and does the Vs and Va try to come up?
Do you here the relays click?

The large cap on the right of the power supply (black dot) does look slightly bulged?
By the way, your model number should be 42HDS69

[Sross002]

Re: TV sometimes doesn't power on.

The standby light stays as a solid red. I do hear the relays click and I see an orange light flick on in the rear of the TV when I hear the relays click, when plugging the TV in. If I leave the TV unplugged overnight, I will get it to start the next day.

[Unspun01]

Re: TV sometimes doesn't power on.

Sross002:

Please follow the advice from my earlier post - Please clean your fans of all dust and see if they move freely. Your TV may trigger a shutdown if fans do not spin up.

Take a deep breath and blow into the fan blades like you would blow up a balloon - They should each spin easily by blowing gently from your mouth.

Then blow very quickly and get the fans to spin as fast as you can - check if they continue to spin , or if they drag to a halt.

DO NOT USE COMPRESSED AIR because you may cause the fans to spin too fast and they are not designed for it.

If you rule out the fans, Please try using a hot air dryer or heat gun (temperature not more than 300C) to warm capacitors or other components on the power board.

These Hitachi Plasma TVs used pretty good capacitors but over time they may have aged. Warming the capacitors may indicate which ones are bad (if any). Make sure you get the small capacitors also since they are often responsible for startup oscillators, etc.

Also, what orange light are you referring to on the back of the TV? Are you talking about the Optical Audio Output jack (red laser diode)? Do you see the standby LED blink an error code at all?

Report back.

[Sross002]

Re: TV sometimes doesn't power on.

Where are the capacitors located? Could I buy new capacitors?
There is an Amber light that flashes inside the back of the TV. The standby light does not blink. Just stays a solid Red.

[Unspun01]

Re: TV sometimes doesn't power on.

This reply is not meant to be rude, but the location of capacitors on the power supply board is self-explanatory. They look... like... capacitors.

If you're not sure what a capacitor looks like, please tell us now so we can understand your level of understanding of electronics. Power supply repair is not for someone who does not understand basic components and you may risk electrocution.

Yes, capacitors can be purchased, but if you do not know what capacitors look like, then perhaps your efforts are better spent having a technician in your area assist you with repair.

[Sross002]

Re: TV sometimes doesn't power on.

You are correct, my level of understanding is minimal when it comes to television electronics. I am not sure what the problem is with the TV and this forum helped me in the past. Since I had a positive experience in the past, I thought I could try again. I thought maybe the problem could be fixed by a novice like myself.

[JayArr_BC]

Re: TV sometimes doesn't power on.

Capacitors are cylindrical things, they may stand on one end and look like the capitol records building in LA or they may be monted on their side and look like a chunk of pipe with two wires that come out one end and turn down into the circuit board. They are usually marked on the circuit board with a C, eg: C352, C456 etc. If you don't know what they are I'm betting you don't have the equipment to test them to see if they are good. You could replace all of them but there may be a couple of dozen by the time your'e done and that's a lot of soldering (can you solder? Do you have soldering gear?)

I think in your case I'd suggest that you purchase a replacement board from shop jimmy or eBay and forget the capacitor replacement avenue.

What's the part number of that big board in the middle?

[steviewonder]

Re: TV sometimes doesn't power on.

Largely speaking,Electrolytic capacitors tend to only work when warm,when failing,not from a cold start. Unlikely to be the problem.

[Unspun01]

Re: TV sometimes doesn't power on.

SRoss002.

Thank you for your reply. Undertaking such a repair without knowledge or tools may result in further damage, or risk to your personal safety.

For your repair, I might suggest complete board replacement rather than board-level repair... However, we need to know which board to replace.

Following my earlier advice, if you can heat up some of the capacitors on the power board for a few minutes (TV unplugged), then plug TV in and try to turn the TV on after warming... I want to see if we can determine which board is causing the problem.

It could be power supply, or mainboard, or another board. You may have to heat the capacitors on various boards (ONE BOARD AT A TIME) to help find your problem board.

See photo for idea what capacitor looks like. They can be big or small..

[Sross002]

Re: TV sometimes doesn't power on.

I will get into the TV as soon as I can find time and get back to you. Thank you for your reply.