Leaking Cap or ink marking?

[redzep]

Hi all--

Newbie here, have searched all day, but cannot figure out if these caps are bad or not. The are not bulging as far as I can tell, but some have these dark purplish marks, that look like they COULD be leaking, but also look like somebody could just have taken a marker and marked them.

This is from a Mintek DTV-260 LCD Color TV.

Many thanks for all your expert opinions.

Best
R

[mariushm]

Re: Leaking Cap or ink marking?

Can't tell from the angle... the camera flash makes it hard to determine how swollen they are.
Pictures made from slightly above the board and from the connectors side would be useful... to see the top of the capacitors.

First impression is that the black ones right between those connectors with lots of wires are bad... same with the blue capacitor at the right end. Check the tops, they should be flat ... check the bottoms as well, if it looks like they're coming out the capacitors may be going bad.

In the end, they could be bad even without showing signs. All capacitors are very close to that large heatsink which is going to be obviously hot while the tv runs. Heat eventually kills capacitors.

[retiredcaps]

Re: Leaking Cap or ink marking?

1) I going to say they all look flat to me with no obvious bulges.

2) What is the problem with the TV?

[c_hegge]

Re: Leaking Cap or ink marking?

It looks like ink to me, but as retiredcaps said, that doesn't necessarily mean they aren't bad.

[shovenose]

Re: Leaking Cap or ink marking?

They look fine to me.

[Evil Lurker]

Re: Leaking Cap or ink marking?

Ink markings.

However, I would yank off the caps on the right hand side of the board and check their ESR... they look a tiny bit bulged. Could be a sign that the ESR is slowly creeping up and the cap are just starting to go bad.

[redzep]

Re: Leaking Cap or ink marking?

Thanks to all for your responses. There is no evident bulging, as the accompanying photos suggest... so maybe it's not the capacitors.

Problem I'm trying to fix: Mintek LCD TV, connected to PC. Turns on and after several minutes, there is a loud POP, and the screen goes black, from outer edges towards center.

Turning TV off then back on fixes situation, but only briefly then it pops back off again. Happens with both VGA and DVI connections, different cables, etc.

Thought that sounded like bad capacitors so I took a look, but consensus seems to be they aren't the culprits. Any other ideas are welcome, and ...

THANK YOU ALL!

[retiredcaps]

Re: Leaking Cap or ink marking?

Any other ideas are welcome, and ...

1) It would help if you posted clear focused top down pictures of all your boards in the following picture composition

https://www.badcaps.net/forum/showpo...94&postcount=1

2) Do you own a multimeter and know how to use it to measure DC voltage?

[redzep]

Re: Leaking Cap or ink marking?

Thanks for your reply

Here is the best I could do, sadly I only have an iphone camera. I do have a multimeter (recently purchased) and I suspect I could figure out how to read DC

Again, all your help is appreciated!

[retiredcaps]

Re: Leaking Cap or ink marking?

1) On the left hand side of your picture are 3 white connectors. This is the "cold" side.

2) Each connector has legend.

3) Put your multimeter on DC voltage.

4) Put your black probe on the ground screw near the connector and leave it there for all readings.

5) Put your red probe on each pin of the connectors. Record all readings.

6) Report your readings like so

CN100
pin 1 says 5V - I get 4.99V
pin 2 says 12V - 11.88V

7) Record the readings BEFORE the TV pops and AFTER so we can compare.

[LITEZONER]

Re: Leaking Cap or ink marking?

I have recently come across a bad cap that showed no obvious signs of being bad, no visible leakage or bulging, I flipped the board over and found that it has leaked through the bottom, through the solder joint. It was really hard to tell, I had to use magnification and a slow roll across the board to find it. Just my two cents.

[redzep]

Re: Leaking Cap or ink marking?

OK first of all a zillion apologies for only being able to get back to this now... it turned in to a busy summer. So I was able to do what you said

And here's what I got with the TV plugged in, turned on, and the white internal connectors plugged in.

C204
GND: 0
BKON (?): 3.6
BKADJ: 1.7v
GND: 0
GND: 0
GND: 0
GND: 0
GND: 0
+24V: 24v
+24V: 24v
+24V: 24v
+24V: 24v
+24V: 24v

C205:
+24: 24
+24V: 24
GND:0
GND:0
-5V: -5.5
GND:0

C206:
BKAJD: 1.7
BKON: 3.6
STB (or ST8): 4.6
GND: 0
GND: 0
GND: 0
+5V: 5.9
+5V: 5.9
+5V: 5.9
+12V: 14.4
+12V: 14.4

Now for someone to interpret these results for me!

Thanks again!

1) On the left hand side of your picture are 3 white connectors. This is the "cold" side.

2) Each connector has legend.

3) Put your multimeter on DC voltage.

4) Put your black probe on the ground screw near the connector and leave it there for all readings.

5) Put your red probe on each pin of the connectors. Record all readings.

6) Report your readings like so

CN100
pin 1 says 5V - I get 4.99V
pin 2 says 12V - 11.88V

7) Record the readings BEFORE the TV pops and AFTER so we can compare.

[redzep]

Re: Leaking Cap or ink marking?

IGNORE ABOVE POST I COULDN'T EDIT IT-- BELOW IS ACCURATE
OK first of all a zillion apologies for only being able to get back to this now... it turned in to a busy summer. So I was able to do what you said

And here's what I got with the TV plugged in, turned on, and the white internal connectors plugged in, both BEFORE the pop, and then a few minutes later, AFTER the pop.

C204
GND: 0
BKON (?): 3.6
BKADJ: 1.7v
GND: 0
GND: 0
GND: 0
GND: 0
GND: 0
+24V: 24v
+24V: 24v
+24V: 24v
+24V: 24v
+24V: 24v

C205:
+24: 24
+24V: 24
GND:0
GND:0
-5V: -5.5
GND:0

C206:
BKAJD: 1.7
BKON: 3.6
STB (or ST8): 4.6
GND: 0
GND: 0
GND: 0
+5V: 5.9
+5V: 5.9
+5V: 5.9
GND: 0
GND: 0
+12V: 14.7
+12V: 14.7

Now for someone to interpret these results for me!

Thanks again!

1) On the left hand side of your picture are 3 white connectors. This is the "cold" side.

2) Each connector has legend.

3) Put your multimeter on DC voltage.

4) Put your black probe on the ground screw near the connector and leave it there for all readings.

5) Put your red probe on each pin of the connectors. Record all readings.

6) Report your readings like so

CN100
pin 1 says 5V - I get 4.99V
pin 2 says 12V - 11.88V

7) Record the readings BEFORE the TV pops and AFTER so we can compare.

[retiredcaps]

Re: Leaking Cap or ink marking?

So I asked for readings before and after. I only see one set of readings in the above post. Are you saying that the readings are identical before and after?

[redzep]

Re: Leaking Cap or ink marking?

Yes readings are the same. A little more detail on the problem: the "pop" comes from the speakers. The screen goes blank, but the green light stays on, which leads me to think that in fact the TV is still on, just the screen (backlight?) is going out? Don't know if this helps. Thanks for sticking with me.

[retiredcaps]

Re: Leaking Cap or ink marking?

C206:
BKAJD: 1.7
BKON: 3.6
STB (or ST8): 4.6
+5V: 5.9
+5V: 5.9
+5V: 5.9
+12V: 14.7
+12V: 14.7

Now for someone to interpret these results for me!

1) The voltage on the 5V and 12V rail on C206 are really high compared to what they are supposed to be.

2) What type of multimeter do you have? Post a picture of it.

3) Where does this connector go to?

[redzep]

Re: Leaking Cap or ink marking?

Thanks for your reply... I have a Radio Shack Cat.No.: 22-172

The third connector goes to the largest board (the one where the VGA DVI inputs are), at a plug labeled P20