Olevia 337-B11 Only turns on when it feels like it

[rpgruss]

Got another puzzler here. The patient is an Olevia 37 inch LCD TV, model 337-B11. The previous owner told me he had the power supply replaced, it worked for a while then would not turn on.

Get it home, it works perfect. Great picture, no problems. It worked all night, watched a few movies. Turn it on the next day, nothing. No picture, no sound. On Olevia TVs, the power light is on when the TV is off, and off when the TV is on. The behavior of the power light indicates the TV is turning on, the light turns off when I press the power button from standby.

If I turn the TV off, the power light comes back on, indicating the TV is in standby. If I turn the TV on and off a few times, it will eventually come on. Once it's on, it doesn't ever stop working. Turn it off, it's a crapshoot if it will work.

Opened it up, didn't see anything 'obviously' wrong. Pictures are below. Any thoughts? I'm wondering if the mainboard is having an issue. Thanks in advance!

[retiredcaps]

Re: Olevia 337-B11 Only turns on when it feels like it

The previous owner told me he had the power supply replaced, it worked for a while then would not turn on.

A replacement power supply, unless brand new from the manufacturer, could be questionable quality.

If I turn the TV on and off a few times, it will eventually come on. Once it's on, it doesn't ever stop working. Turn it off, it's a crapshoot if it will work.

It sounds like a classic case of caps with high ESR. As the caps warm up, the ESR drops allowing the TV to work.

A hair dryer may come in handy?

Alternatively, when the TV doesn't work, see if the DC voltages are fluctuating or low.

Pictures are below.

Take a look at the inverter board as well.

[rpgruss]

Re: Olevia 337-B11 Only turns on when it feels like it

No hair dryer, and it hasn't failed yet today to check voltages. I pulled the power supply out and used and ESR meter on all the caps on the secondary side; all of them appear to be good (none over 1 ohm except a 22uf which read 1.9 ohms). Some of the caps did seem to take a bit to 'settle' on a number, is this indicative of a problem? Also, do I need to worry about the primary side capacitors? I tried to measure one and it bounced all over the place for a good couple of seconds, longer than any on the secondary. Not sure if this is due to the switching circuitry interfering or what.

[Mr Bill]

Re: Olevia 337-B11 Only turns on when it feels like it

one of my panasonic fc 22uf caps reads .28ohm esr so that 1.9 may be suspect. Even 1ohm esr may be out of spec if they are low esr caps. What is the brand and series of the caps in the power supply?

[rpgruss]

Re: Olevia 337-B11 Only turns on when it feels like it

Ok, I was thinking recapping was in order, now I'm definitely on board for that!

The capacitors are all Lelon RXW, except one Elite EL series.

I do have a problem identifying one capacitor, they put the friggin glue right over the value and voltage. If you look at the left side of the power supply, there are 2 heat sinks. Below the lower one, there are 2 smaller capacitors to the left of a bigger one. The little one on the left is the culprit. Is it safe to assume that is cap would have the same values as it's neighbor? The one I can read is 22 uf and is the one that reads 1.9 ohms.

[Mr Bill]

Re: Olevia 337-B11 Only turns on when it feels like it

Here is the datasheet for the lelon rxw caps. Lookup a few you have and see if the impedance is within spec. I would recap because lelon's are known for failure. As for the glue, you should be able to pick it off to see the value. It may be easier once you remove the caps that are in that area.

[cashkennedy]

Re: Olevia 337-B11 Only turns on when it feels like it

At first i thought your problem might be similar to the ones I and a few other people had with the olevia 342-b11, which we fixed here https://www.badcaps.net/forum/showth...=olevia+mosfet

But, those tv's wouldnt ever turn on cause there were fried mosfets. Also they have a different brand power supply, but possibly olevia submits a design to a company to make, and thus designed both.

Either way id suggest you check the mosfets as well on the power board if replacing the caps doesnt help.

And yes i absolutely hate the interior logic (OSD, menus, and function of the power light) on my 342-b11, it also takes like 30 seconds to turn on which is ridiculous. Its like, ok you pressed power on the remote, 10 seconds later it turns off the blue led, 10 seconds later it shows the olevia logo, and finally another 10 seconds later it is useable.

[rpgruss]

Re: Olevia 337-B11 Only turns on when it feels like it

Welp, looks like most caps are out of spec or very close to the line. Digikey time. Thanks a ton for that datasheet!

As for the mystery cap: the glue is this awful awful white crap that is super hard and takes most of the capacitor label off with it. I don't think I'll be reading that cap.

[rpgruss]

Re: Olevia 337-B11 Only turns on when it feels like it

At first i thought your problem might be similar to the ones I and a few other people had with the olevia 342-b11, which we fixed here https://www.badcaps.net/forum/showth...=olevia+mosfet

But, those tv's wouldnt ever turn on cause there were fried mosfets. Also they have a different brand power supply, but possibly olevia submits a design to a company to make, and thus designed both.

Either way id suggest you check the mosfets as well on the power board if replacing the caps doesnt help.

And yes i absolutely hate the interior logic (OSD, menus, and function of the power light) on my 342-b11, it also takes like 30 seconds to turn on which is ridiculous. Its like, ok you pressed power on the remote, 10 seconds later it turns off the blue led, 10 seconds later it shows the olevia logo, and finally another 10 seconds later it is useable.

I actually read that thread! As I mentioned, the TV was previously fitted with a new power supply, so it is entirely possible that a substitute was installed. I do have the original power supply, it has burned mosfets on it. May need to fix that up.

[rpgruss]

Re: Olevia 337-B11 Only turns on when it feels like it

Got the new caps in, still having the same issue. I only replaced the caps on the secondary side; I've been told those are the ones under the most stress. Would it be worthwhile to replace the primary side ones, or should I be looking elsewhere?

Retiredcaps: I checked the voltage, there are no descriptions of the pinouts, so I'm guessing here. What looks like the 12v line only has 8 volts when the tv won't turn on. Standby line does go low though, it drops from 5v to 3.5v.

I also have the original power supply, I put it in the tv and the front standby LED started blinking. Checked the voltage, and it is all over the place. Hard to tell the exact range as I have a digital meter, but around 2-5v. Maybe I should try to fix this one instead?

[retiredcaps]

Re: Olevia 337-B11 Only turns on when it feels like it

Would it be worthwhile to replace the primary side ones, or should I be looking elsewhere?

Yes, on the primary side is the very important startup cap. It is usually 47uF 50V.

[selldoor]

Re: Olevia 337-B11 Only turns on when it feels like it

Hi there is usually a small 50v cap on the primary side which is the startup cap.
Perhaps you could list the caps and we could make a guess which one it is.
I will look through that other thread to see if I can spot anything.
In the meantime perhaps you could try retiredcaps hairdrier plan.

Before you try and turn it on heat the small caps in the primary area with the hairdrier and see if it comes on straight away.

Edit - Ha beat me to it - that'l teach me to watch tv at the same time

[rpgruss]

Re: Olevia 337-B11 Only turns on when it feels like it

Here are all the caps on the primary side:

470uf 35v
22uf 50v (5x)
47uf 50v
4.7uf 50v
150uf 450v
One unknown, they put this stupid hard glue right over the numbers, but based on the size and location I figure it is 47uf 50v.

All are Lelon RXW series caps, except the big kahuna which is a Nippon Chemi Con KMQ

[mjlewis422]

Re: Olevia 337-B11 Only turns on when it feels like it

Hi there is usually a small 50v cap on the primary side which is the startup cap.
Perhaps you could list the caps and we could make a guess which one it is.
I will look through that other thread to see if I can spot anything.
In the meantime perhaps you could try retiredcaps hairdrier plan.

Before you try and turn it on heat the small caps in the primary area with the hairdrier and see if it comes on straight away.

Edit - Ha beat me to it - that'l teach me to watch tv at the same time

What if the hairdryer trick does work? What does that mean?

[retiredcaps]

Re: Olevia 337-B11 Only turns on when it feels like it

What if the hairdryer trick does work? What does that mean?

Answered in post #2.

[mjlewis422]

Re: Olevia 337-B11 Only turns on when it feels like it

I was mainly trying to figure out if it was the power supply or the inverter board that was the most likely culprit. I just ordered a new psu board (haven't had any luck with the inverter board yet) so, I'll see what happens.