Atlas 37AV500U popping sound

[tibimakai]

Re: Atlas 37AV500U popping sound

it can't be one or more of the 120V input filter capacitors that went bad?
I have re read all the posts and I have just realised that I haven't checked budm's idea to check the audio output signal if it pops too.
Later today I will check out this one too.

[tibimakai]

Re: Atlas 37AV500U popping sound

OK with an RCA cable connected to an exterior amplifier I don't have the popping sound anymore.
So it looks like it's coming from the amplifier. Am I right?
I'm open to suggestions, which component could be at fault here?
I can take more pictures if needed.

[budm]

Re: Atlas 37AV500U popping sound

That will be the Class D power amp IC which drive the speakers, they usually are two channels in one chips. We will need the pictures of the main board, the cable from the speakers plug into the connector on the main board will be real close to where the amplifiers are.
Picture #3 on post #6, it look like the power amp is the one with small heat sink on top and the two inductors for the switching noise filter on each side. but I cannot tell where the output connector is.

[tibimakai]

Re: Atlas 37AV500U popping sound

the output is on the top of the amplifier, those four wires connector. red/black and white/green wires going to that small board with four big capacitors and from there to the speakers. Those four capacitors are new.
All the electrolytic capacitors(the through hole) are replaced on the mainboard too. Most likely it's a SMD capacitor will be the issue?
this is off topic, I have "played" with the four panel flex cables on the Vizio 46" tv and I reconnected it while it was on and I messed up something, because I don't have the blue screen anymore, just the backlight. No voltage coming through the fuse either. Do you think that the issue is on the mainboard, one of the regulators it's blown?

[budm]

Re: Atlas 37AV500U popping sound

We need to get the heatsink off the IC to get P/N or we have to get the service manual to find out how the IC is connected.
The Vizo, are you talking about the fuse on the T-CON board, it should have 12vdc on that fuse which is supplied through a switched transistor on the main board.

[tibimakai]

Re: Atlas 37AV500U popping sound

in the service manual there is not much, almost nothing and it's a bit different then my TV.
Do you know a good way of removing a heatsink like this? It's pretty stuck.
Last time I have twisted off a Y buffer heatsink I ripped off the chip too.
Maybe I should get another amplifier and use that in stead of the original

[selldoor]

Re: Atlas 37AV500U popping sound

I am throwing this in for comment as I dont really know if it is relevant.
I believe inductors are used a lot in audio circuits to prevent popping
from caps charging/discharging. There are two, L3 & L4 in the area being discussed and wonder if there is a way of testing them, before wrestling with the ic.

[tibimakai]

Re: Atlas 37AV500U popping sound

I have just twisted off the heatsink.
The IC is a TPA3100D2.(7C7/DK7V)
I will try testing them with an ohm meter.
I'm reading something about the pop on page 23-24.
https://cdn.badcaps-static.com/pdfs/...fc56812a68.pdf
The dot on the chip is at the lower left side if you look at the pictures above.
I think that C127(on the right/lower side of the chip) is that capacitor which controls the pop.

[budm]

Re: Atlas 37AV500U popping sound

The Inductors and the capacitors are for filtering the Class D switching noise and PWM to demodulate the audio from PWM, a little hard to explain.
I would find the VCC pin and see if the voltage is spiking up and down in sync with the poping sound since both channels are doing it, then it should be something that is common to both channels. I believe that is for turn on and turn off pop reduction when you apply/remove power to the IC, I would monitor that pin also.

[tibimakai]

Re: Atlas 37AV500U popping sound

it's possible to use a multimeter for this test?

[budm]

Re: Atlas 37AV500U popping sound

Just set the meter to DC and chekc the VCC pins and other pins see if the numbers jump up and down, I hope your meter has enough fast response to catch the pulse.

[tibimakai]

Re: Atlas 37AV500U popping sound

Unfortunately I can't see the spike(if there is one) because it happens instantly.
It can't be one of the capacitors at the 120V input?
Any other ideas?
I can't sell this TV because of a pop.

[tibimakai]

Re: Atlas 37AV500U popping sound

Found a Sony schematic which uses the same Amp IC, maybe it can help.
I have tried the snipping tool, but it's hard to see the writing.
How can I include a page from a SM in here?
The Sony 40V4150 has this IC. Page 43
http://elektrotanya.com/?q=showresult

[tom66]

Re: Atlas 37AV500U popping sound

Unfortunately I can't see the spike(if there is one) because it happens instantly.
It can't be one of the capacitors at the 120V input?
Any other ideas?
I can't sell this TV because of a pop.

I have sold TVs before with faulty sound to people who use them with home cinemas.

[tibimakai]

Re: Atlas 37AV500U popping sound

In the worst case I will sell it a bit cheaper, but I would also like to learn about this problem.
Even that Vizio with those semi circles I have sold it, much cheaper though.
But another thing I don't understand, the previous owner said that the TV some times would not turn on.
To me it turns on all the time and has a great picture and sound.
I have replaced all the caps, even on the main board, just to be sure.
What do you do in a case where you get a TV with an "issue" and for you the TV works perfectly? Do you just sell it or keep it for a while, just to make sure that doesn't come back that issue?

[tom66]

Re: Atlas 37AV500U popping sound

In the worst case I will sell it a bit cheaper, but I would also like to learn about this problem.
Even that Vizio with those semi circles I have sold it, much cheaper though.
But another thing I don't understand, the previous owner said that the TV some times would not turn on.
To me it turns on all the time and has a great picture and sound.
I have replaced all the caps, even on the main board, just to be sure.
What do you do in a case where you get a TV with an "issue" and for you the TV works perfectly? Do you just sell it or keep it for a while, just to make sure that doesn't come back that issue?

On all my TVs I do a burn in test. I leave it on for all night. I then give it to my dad who uses it for a couple of weeks before it is sold. Bonus he doesn't have to use a 26" CRT and can enjoy a 42" Plasma from time to time and it gets a good test.

[tibimakai]

Re: Atlas 37AV500U popping sound

Thanks. That is what I'm doing with the Sony that I had to just reset to factory settings(turn off/on a couple of times and 10 blinks) and I have applied the latest firmware.
It's been a month of nightly use, which I think that it's enough.

By the way, this is way off topic, but I'm in a hurry here.
I'm about to pick up a Sony 40V4150 with a no power on and 13 blinks. It seems like an inverter error. Do you have experience with this? I couldn't find the error code meaning in the SM.
There is another one that I could pick up, but I'm affraid of it, it's a 40S4100 which has a 1/4 of the screen is black(vertical line).

[tom66]

Re: Atlas 37AV500U popping sound

By the way, this is way off topic, but I'm in a hurry here.
I'm about to pick up a Sony 40V4150 with a no power on and 13 blinks. It seems like an inverter error. Do you have experience with this? I couldn't find the error code meaning in the SM.
There is another one that I could pick up, but I'm affraid of it, it's a 40S4100 which has a 1/4 of the screen is black(vertical line).

No experience with Sony, wish I did though, they are pretty well made.

The other Sony sounds like a loose ribbon for 1/4 of the screen (common 1080p T-con has four ribbons) - could be an easy fix - could also be a bad panel though.

[tibimakai]

Re: Atlas 37AV500U popping sound

I didn't know that the 1080p has four cables and each controls a 1/4 of the screen. So on regular TVs where there are only two, then each controls half the screen. Am I right?
I thought that there are four because the screen is bigger.

[tom66]

Re: Atlas 37AV500U popping sound

I didn't know that the 1080p has four cables and each controls a 1/4 of the screen. So on regular TVs where there are only two, then each controls half the screen. Am I right?
I thought that there are four because the screen is bigger.

I guess so - but I've only serviced two 1080p sets - and only one of them had a 1080p board with 4 ribbons, but I've seen pics of T-cons for 1080p Samsung and Sony (same as Samsung panel, at least older models) and they almost always have four ribbons. Look for T-con for that model, see if that is true. Worst case, maybe the T-con is bad for that ribbon, maybe each ribbon is individually driven.