LC-42SB45U Needs To Warm Up To Turn On

[DerbyDad03]

Greetings from a first time poster.

I am having problems with my Sharp LC-42SB45U LCD TV S/N 810873158.

The unit takes roughly 45 seconds to power on when cold. When the device was working correctly, I would attempt to power the device on and the red standby indicator would go off for a second or so, then the green power indicator would come on.

Now when I try to power the device on, the red standby light will go out and it could take anywhere from 30 to 45 seconds before anything happens. What then happens is that most of the time the green power light will come on. However, sometimes - even after waiting 30-45 seconds - the red light will come back on and I'll have to try to power on the device again. Other times the green light will flash then quickly change to red and I'll have to try to power on the device again.

When the device doesn't power on after the 30-45 seconds, the cycle time for those "other" symptoms drops down to a few seconds. e.g. I'll wait 30-45 seconds and the red light will come back on. I'll try to power the unit on and the red light will go off then come back on after, let's say, 10 seconds. I hit power again and it might flash off and then back on immediately. Eventually, the green light will come on and stay on. It may take as many as 5 attempts to get the unit to power on.

I tested the "power on time" after the unit has been on for a few hours and it appears that the the unit comes on immediately once it has warmed up. I cycled it 2 or 3 times and it powered on normally each time, but I've only done that test once. I can repeat that test this evening if need be.

As far as I can tell, something needs to warm up before the unit will power on but I'm not sure where to start looking. I could try a heat gun (on low) but I'd like to have an idea as to what I should be heating up, e.g. the power supply board or the main board or something else. I could also put a space heater under the set to "pre-warm" it to see if the symptoms go away. As I said, I suspect it's a warm-up issue, but I could be wrong.

Any troubleshooting tips would be appreciated. Thanks!

[budm]

Re: LC-42SB45U Needs To Warm Up To Turn On

It sounds like bad cap with high ESR, once the unit warms up the ESR will go down and allow the unit to function again.
How about uploading good clear pictures of the whole back side of the TV so we can see how all the boards are connected together? and then good clear pictures of the power supply board.

[DerbyDad03]

Re: LC-42SB45U Needs To Warm Up To Turn On

It sounds like bad cap with high ESR, once the unit warms up the ESR will go down and allow the unit to function again.
How about uploading good clear pictures of the whole back side of the TV so we can see how all the boards are connected together? and then good clear pictures of the power supply board.

Thanks for the response. I'll take the pictures, but it'll be a few days. I'll need to remove the TV from the wall mount, etc. It may have to wait until the weekend, but I'll get to it.

[DerbyDad03]

Re: LC-42SB45U Needs To Warm Up To Turn On

Here are some pictures of the power supply board. There is at least one bulging & leaking cap, so I'll head out to my favorite indy electronics store for one on Monday. If you guys see anything else that looks suspicious, please let me know.

Thanks for your help!

Overall Power Supply View

Note the cap in the lower right corner. There was more of the innards on top of the cap before I vacuumed the board.



Close Ups Of Bad Cap:

Before Cleaning



After Cleaning, Side View



Half Views of Power Supply



Bad Cap in upper right:

[ReeceyBurger123]

Re: LC-42SB45U Needs To Warm Up To Turn On

Look up what a bad capacitor is. You have one ! See the picture I attach the device with yellow stuff out the top is failed and will need to be changed.

[freakaftr8]

Re: LC-42SB45U Needs To Warm Up To Turn On

Yes the green one on the upper right side just above the yellow transformer looks like c850 something that's bad replace it. Bet your problems would go away.

[DerbyDad03]

Re: LC-42SB45U Needs To Warm Up To Turn On

Look up what a bad capacitor is. You have one ! See the picture I attach the device with yellow stuff out the top is failed and will need to be changed.

Thanks for verifying that the cap I pointed out in my post is the obvious bad one.

I assume that means that you don't see anything else that looks suspicious, correct?

[DerbyDad03]

Re: LC-42SB45U Needs To Warm Up To Turn On

Yes the green one on the upper right side just above the yellow transformer looks like c850 something that's bad replace it. Bet your problems would go away.

Thanks. I hope the leaky one is the only bad one. Nothing else appears to be bulging or leaking, so I try that one and see what happens.

Thanks again.

[ReeceyBurger123]

Re: LC-42SB45U Needs To Warm Up To Turn On

Wait ! The green cap is a defective series, you must replace the others as well if not you will have the same issue a few months down the line.

[DerbyDad03]

Re: LC-42SB45U Needs To Warm Up To Turn On

Wait ! The green cap is a defective series, you must replace the others as well if not you will have the same issue a few months down the line.

What do you mean by "the others". There's a lot of caps on that board.

Do you mean the 3 other large green caps between the 2 heat sinks?

[ReeceyBurger123]

Re: LC-42SB45U Needs To Warm Up To Turn On

Yes the other large green caps.

[DerbyDad03]

Re: LC-42SB45U Needs To Warm Up To Turn On

Yes the other large green caps.

Do you know if all 4 caps are 2700uF, 16V? I only looked at the leaky one.

I've already mounted the TV back on the wall. Football!

Thanks again.

[ReeceyBurger123]

Re: LC-42SB45U Needs To Warm Up To Turn On

You will need to take the back off to check them again, I really do urge you to replace them mate.

[DerbyDad03]

Re: LC-42SB45U Needs To Warm Up To Turn On

You will need to take the back off to check them again, I really do urge you to replace them mate.

Oh, I do plan to replace them. I was just trying to avoid unmounting the TV again. I left most of the cover screws out, so taking the back off will be quick once I get it off the mount.

I found this kit on eBay, which claims it's for my model TV, but there is no 2700uF cap in the parts list. As you can see from my picture, the cap that is leaking reads 2700uf. This kit won't work, will it?

http://www.ebay.com/itm/Sharp-LC42SB...4AAOSwjVVVxP9x

Thoughts?

[DerbyDad03]

Re: LC-42SB45U Needs To Warm Up To Turn On

Nevermind...I found a kit that includes all of the caps I need.

I'll let you know how it works out.

Thanks for the help so far.

[ReeceyBurger123]

Re: LC-42SB45U Needs To Warm Up To Turn On

Cool beans mate, let us know how it goes

[DerbyDad03]

Re: LC-42SB45U Needs To Warm Up To Turn On

It's the age old question: Does size matter?

As you may recall, it was suggested that I replace all 4 of the green CapXon caps on the Power Supply board shown below. I should mention at this point that by the time it was suggested that I replace all 4 CapXon caps I had already closed up the TV. I did not check the values of the caps in the "group of three" in the upper right. The only cap I know the value of is the leaky one in the lower right, which is speced at 2700uF, 16V.



The component list for the kit I ordered from eBay, which was specified for my model TV, contained a 2700uF cap, so I took it on faith that it was the correct kit. Now that I have received the kit, I am no longer so sure. The first thing I noticed was that there is only one "large" cap that is roughly the same physical size as the CapXon caps. That cap is rated at 2700uf 25V, not 2700uf 16V. Based on what I remember about caps from a previous life, that shouldn't be a problem, correct?

Next, assuming that when I open the TV I am able to match values from the kit with the other 3 CapXon caps, it's obvious that none of them are going to be even close to the same physical size. Will that matter?

Now, one way or another I am going to have to take the TV off the wall to check the values, but I'm just looking for some wisdom as far the kit goes. In other words, when I open up the TV, will I be able to complete the operation at that time or will it just be a repeat of the exploratory surgery so that I can determine the values of the "group of three" and get those caps elsewhere?

This is the description of the kit as shown on eBay:

11 High Temperature capacitors:
2700uF (1),
1000uF (1),
680uF (2),
100uF (1),
47uF (2),
33uF (1),
22uF (1),
10uF (2)
Kit does not include the large 400-450v capacitors

Here is what I received, so you can see what I mean about the sizes:



Assuming some of the smaller caps match the values of the 3 CapXon caps, can I use them even if the physical size is so much smaller?

BTW...I mentioned "remembering caps from a previous life". I used to work with large, oil caps like this about 40 years ago while serving in the US Coast Guard. They were used in mega-watt LORAN transmitters that used vacuum tubes with 15KV DC plate voltages. Scary stuff!

[clapp]

Re: LC-42SB45U Needs To Warm Up To Turn On

It's the age old question: Does size matter?

As you may recall, it was suggested that I replace all 4 of the green CapXon caps on the Power Supply board shown below. I should mention at this point that by the time it was suggested that I replace all 4 CapXon caps I had already closed up the TV. I did not check the values of the caps in the "group of three" in the upper right. The only cap I know the value of is the leaky one in the lower right, which is speced at 2700uF, 16V.



The component list for the kit I ordered from eBay, which was specified for my model TV, contained a 2700uF cap, so I took it on faith that it was the correct kit. Now that I have received the kit, I am no longer so sure. The first thing I noticed was that there is only one "large" cap that is roughly the same physical size as the CapXon caps. That cap is rated at 2700uf 25V, not 2700uf 16V. Based on what I remember about caps from a previous life, that shouldn't be a problem, correct?

Next, assuming that when I open the TV I am able to match values from the kit with the other 3 CapXon caps, it's obvious that none of them are going to be even close to the same physical size. Will that matter?

Now, one way or another I am going to have to take the TV off the wall to check the values, but I'm just looking for some wisdom as far the kit goes. In other words, when I open up the TV, will I be able to complete the operation at that time or will it just be a repeat of the exploratory surgery so that I can determine the values of the "group of three" and get those caps elsewhere?

This is the description of the kit as shown on eBay:



Here is what I received, so you can see what I mean about the sizes:



Assuming some of the smaller caps match the values of the 3 CapXon caps, can I use them even if the physical size is so much smaller?

BTW...I mentioned "remembering caps from a previous life". I used to work with large, oil caps like this about 40 years ago while serving in the US Coast Guard. They were used in mega-watt LORAN transmitters that used vacuum tubes with 15KV DC plate voltages. Scary stuff!

Physical Size doesn't matter my friend.
as long as the Farad Value Matches, and the Voltage rating is the same or Higher it will work just fine

[DerbyDad03]

Re: LC-42SB45U Needs To Warm Up To Turn On

Physical Size doesn't matter my friend.
as long as the Farad Value Matches, and the Voltage rating is the same or Higher it will work just fine

That's what I was hoping to hear.

The girls are home from college for the Thanksgiving break. In deference to my health and well being, I won't be attempting the repair until after they go back to school.

They'll be no living with them (or SWMBO) if I disable their Netflix/Food Channel/Say Yes To The Dress for any length of time.

Me Them
.↓...↓

[ReeceyBurger123]

Re: LC-42SB45U Needs To Warm Up To Turn On

Haha let us know how it goes in the end