Toshiba TV29C90 problem; Image fades to black...

[Malissa Baldwin]

James Sweet wrote:

Do you have a multimeter, soldering tools, and a basic understanding of
how a television set works?

Do you, or do you just jizz on the circuit board?

 

[Malissa Baldwin]

George Jetson wrote:

Someone gave me a Samsung 27" TV, Model TXL2791F. When I tried to turn
it on it did nothing. No indication of power at all. I opened it up and
checked the fuses. All good.

You didn't say that you plugged it in, asshole, maybe you should try
doing that.

I got a copy of the schematics, and did a little circuit tracing.
There's a component called a flyback transformer, which is connected to
a component called a high voltage tripler, which is connected to the CRT
high voltage anode. There's a picture of it at
http://www.wehaveparts.com/index.cgi?product=&pid=1553&cart_id=
1146478751 . The picture says it's a flyback transformer, but according
to the schematic it's the tripler. The schematic just shows a box. No
internal wiring.

The thick wire shown in the picture goes to the CRT anode, the thin wire
goes to a ground, and the hole is for a thick wire from the flyback.

That's the wire that the cable company sends the picture to the tube.

When I pull the ground off, I can turn the TV on with the switch as well
as the remote. After removing the ground, when I plug it in I hear the
slight crackling/humming sound that means the set is powering up, and a
red LED comes on that means the set is powered up but off. When I press
the ON switch or the remote, the LED turns green, and I get a tone that
means I need to set up the time, channels, etc. I get no picture, of
course, because there's no voltage to the CRT, but everything else seems
to indicate that the TV is starting to power up normally.

If there is no voltage to the CRT, then how the fuck would you know
that the time and channels need to be set up.

When the ground wire is connected, presing the switch or the remote gets no
reaction at all.

That's probably because the ground wire is connected to the switch,
stupid.

No, my question. Would this indicate a problem with the tripler? Or the
flyback? What's a good way to test? I am familiar with radio and
computer repair, but I've never worked with televisions, and I don't
have any high voltage test equipment. Thanks for the help.

Well then, you're fucked.

Oh, and I'm aware that the voltages in a TV can kill me, so I take
proper safety precautions, so no need to remind me. Thanks for the
thought, though.

Fuck it and just throw it away and buy a Protron.

 

[Rick Brandt]

George Jetson wrote:

Charlie Morgan <*@*.com> wrote in
news:ctm5p25j3ajetaf4ctpjf0p0flrnmf34sn@ 4ax.com:


I don't have any idea what's on TV tonight, but I am thinking you
are going to miss it. <G

CWM


Maybe, but not for lack of a working TV. I have three.

One of the more common (totally dead) failures I see is a cracked circuit board
which interrupts some of the circuit traces. This is common in the area of the
flyback due to its weight. If the set is dropped or otherwise subjected to
sufficient G-forces the weight of the flyback causes enough board flex to crack
it. Sometimes these are easy to see, sometimes finding all of them can be a
real tough nut.

 

[George Jetson]

I'll ignore everything else you wrote, except this. I think you really
don't know this.

"Malissa Baldwin" <ziggylikesnakedmen@yahoo.com> wrote in
news:1167254546.241341.104590@i12g2000cwa.googlegroups.com:

If there is no voltage to the CRT, then how the fuck would you know
that the time and channels need to be set up.

Remember what I said? "I get a TONE that means I need to set up the time,
channels, etc." A tone. As in sound. Sounds don't go through the CRT, you
feeble minded bitch.

 

[CptDondo]

Malissa Baldwin wrote:

You didn't say that you plugged it in, asshole, maybe you should try
doing that.

That's the wire that the cable company sends the picture to the tube.


If there is no voltage to the CRT, then how the fuck would you know
that the time and channels need to be set up.

That's probably because the ground wire is connected to the switch,
stupid.

Well then, you're fucked.


Fuck it and just throw it away and buy a Protron.

Take a shit, have an orgasm, do what it takes, but lose that attitude.

 

[George Jetson]

"Rick Brandt" <rickbrandt2@hotmail.com> wrote in
news:KFBkh.7622$yC5.867@newssvr27.news.prodigy.net:

One of the more common (totally dead) failures I see is a cracked
circuit board which interrupts some of the circuit traces. This is
common in the area of the flyback due to its weight. If the set is
dropped or otherwise subjected to sufficient G-forces the weight of
the flyback causes enough board flex to crack it. Sometimes these are
easy to see, sometimes finding all of them can be a real tough nut.

The set is only a few years old, and the flyback is relatively light. I
also looked at the circuit card and didn't see any marks or cracks at
all. And to be honest, I'm not sure it's the flyback. There's a
component called a High Voltage Tripler that sits between the flyback
and the CRT. When I take the tripler out of the circuit the set powers
up and goes through a short diagnostic. With the tripler in it does
nothing at all.

On the schematic the tripler is just a box, with an input, output, and
ground. If the triler is some kind of step up transformer, wouldn't the
resistance across the input and output be infinity? I measured it at a
little over a hundred ohms. Would that indicate a shorted tripler?
That's what I suspect, but I don't know exactly how the tripler is set
up. Any advice?

 

[Rick Brandt]

George Jetson wrote:

The set is only a few years old, and the flyback is relatively light.
I also looked at the circuit card and didn't see any marks or cracks
at all. And to be honest, I'm not sure it's the flyback. There's a
component called a High Voltage Tripler that sits between the flyback
and the CRT. When I take the tripler out of the circuit the set powers
up and goes through a short diagnostic. With the tripler in it does
nothing at all.

On the schematic the tripler is just a box, with an input, output, and
ground. If the triler is some kind of step up transformer, wouldn't
the resistance across the input and output be infinity? I measured it
at a little over a hundred ohms. Would that indicate a shorted
tripler? That's what I suspect, but I don't know exactly how the
tripler is set up. Any advice?

Well any time you take a component out of the circuit and get more functionality
than when it is in place that is pretty good evidence that you are in the right
area, but the real problem might be downstream of the tripler and removing it
from the circuit might also be taking other things out of the circuit that are
the real problem.

That's what sucks about trying to fix this stuff as a consumer. At the shop
they would try the tripler and if that wasn't it they could grab any of a
hundred other parts at their disposal and try them. Ordering your first best
guess on-line, waiting for it to arrive, and then trying it only to find that it
doesn't fix the problem is a hell of a way to make progress. Short of seeing
parts that are visibly damaged it really is a crap-shoot.

 

[Meat Plow]

On Wed, 27 Dec 2006 09:58:20 -0800, b w Has Frothed:

Is there any remedy for fixing scratches on big screen tvs? it is a
rear projection tv, the replacement screen is 460 bucks from JVC, i can
just replace that if i need to but i would rather try to make the
scratch less noticeable...

it feels pretty deep but i cant really tell, it mainly took the anti
glare off i think, please help i just want to minimize it if at all
possible
Thanks
Brandon

Really nothing you can do that won't mar the surface further.
--
Pierre Salinger Memorial Hook, Line & Sinker, June 2004

COOSN-266-06-25794

 

[George Jetson]

"Rick Brandt" <rickbrandt2@hotmail.com> wrote in
news:VdCkh.7627$yC5.7102@newssvr27.news.prodigy.net:

Well any time you take a component out of the circuit and get more
functionality than when it is in place that is pretty good evidence
that you are in the right area, but the real problem might be
downstream of the tripler and removing it from the circuit might also
be taking other things out of the circuit that are the real problem.

That's what sucks about trying to fix this stuff as a consumer. At
the shop they would try the tripler and if that wasn't it they could
grab any of a hundred other parts at their disposal and try them.
Ordering your first best guess on-line, waiting for it to arrive, and
then trying it only to find that it doesn't fix the problem is a hell
of a way to make progress. Short of seeing parts that are visibly
damaged it really is a crap-shoot.


If I knew what was inside the tripler I could test it. I have a

schematic of the flyback, but I would have to unsolder it to test, and
I'm trying to avoid that. If I can test the tripler and it turns out
bad, I can avoid unsoldering the flyback.

 

[Ken Weitzel]

George Jetson wrote:

"Rick Brandt" <rickbrandt2@hotmail.com> wrote in
news:VdCkh.7627$yC5.7102@newssvr27.news.prodigy.net:

Well any time you take a component out of the circuit and get more
functionality than when it is in place that is pretty good evidence
that you are in the right area, but the real problem might be
downstream of the tripler and removing it from the circuit might also
be taking other things out of the circuit that are the real problem.

That's what sucks about trying to fix this stuff as a consumer. At
the shop they would try the tripler and if that wasn't it they could
grab any of a hundred other parts at their disposal and try them.
Ordering your first best guess on-line, waiting for it to arrive, and
then trying it only to find that it doesn't fix the problem is a hell
of a way to make progress. Short of seeing parts that are visibly
damaged it really is a crap-shoot.


If I knew what was inside the tripler I could test it. I have a
schematic of the flyback, but I would have to unsolder it to test, and
I'm trying to avoid that. If I can test the tripler and it turns out
bad, I can avoid unsoldering the flyback.

Hi..

http://tpub.com/neets/book7/27m.htm

Ken

 

[Jamie]

hondgm@yahoo.com wrote:

I'm looking for opinions on handheld oscilloscopes. To give you an
idea of what I'm looking for, something like a TPI 460
(http://www.tequipment.net/TPI460.asp) would suit me well, since it
looks to be well-designed with a 3 year warranty, and doubles as a
standard multimeter. But, I really don't need anything rugged, and a
higher sampling rate would be nice. The Protek 840 looks very nice for
a few hundred extra dollars, but I'm not familiar with them.

I'd prefer new over used, and looking to spend US$1000-1500. Any good
or bad experiences? How about these Chinese OWON brand scopes, anyone
use these?

You might like this one better.

it's not quite 600V, it goes up to 400v.
other than than , it makes for a nice thingy..
it's a DMM and Dual scope in color., all inputs
are isolated from each other, that makes it nice
for testing different sources with out causing
shorts.
http://www.saelig.com/miva/merchant.mvc?Screen=PROD&Product_Code=PSSA001&Category_Code=PSSA



--
"I'm never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

 

[Jamie]

hondgm@yahoo.com wrote:

I'm looking for opinions on handheld oscilloscopes. To give you an
idea of what I'm looking for, something like a TPI 460
(http://www.tequipment.net/TPI460.asp) would suit me well, since it
looks to be well-designed with a 3 year warranty, and doubles as a
standard multimeter. But, I really don't need anything rugged, and a
higher sampling rate would be nice. The Protek 840 looks very nice for
a few hundred extra dollars, but I'm not familiar with them.

I'd prefer new over used, and looking to spend US$1000-1500. Any good
or bad experiences? How about these Chinese OWON brand scopes, anyone
use these?

Yes, to add to it., i just bought one of those OWON.

if you look at the URL i gave you, i think you'll like the
price.


--
"I'm never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

 

[Homer J Simpson]

"b w" <aquateenhungerforce1@gmail.com> wrote in message
news:1167242300.839957.249280@a3g2000cwd.googlegroups.com...

Is there any remedy for fixing scratches on big screen tvs?

You could try someone who does plastic fabrication / welding.

 

[George Jetson]

Ken Weitzel <kweitzel@shaw.ca> wrote in news:ibDkh.530079$5R2.359199
@pd7urf3no:

Hi..

http://tpub.com/neets/book7/27m.htm

Ken

Thanks for the info. I tested it, and the tripler is bad. It's shorted
between the primary and the secondary. I'll order a new one and hook it up,
and let everyone in the newsgroup know if it worked. Assuming I don't
electrocute myself.

 

[Art]

Is the scratch on teh Lenticular Screen or on the Clear Screen Protector?
If the mar is on the protector, optical quality plexiglass can be cut to the
size of the protector and used.
However, if the mar is on the Lenticular screen then buying another screen
is the only answer.
"Homer J Simpson" <nobody@nowhere.com> wrote in message
newsNDkh.100187$hn.62040@edtnps82...

"b w" <aquateenhungerforce1@gmail.com> wrote in message
news:1167242300.839957.249280@a3g2000cwd.googlegroups.com...

Is there any remedy for fixing scratches on big screen tvs?

You could try someone who does plastic fabrication / welding.

 

[JR North]

Try filling the scratch with thick CA. Will take some dexterity, and
perhaps a fine needle and mag glass. Can't say how it will affect the
optics. Maybe try a small area for test.
JR

b w wrote:

Is there any remedy for fixing scratches on big screen tvs? it is a
rear projection tv, the replacement screen is 460 bucks from JVC, i can
just replace that if i need to but i would rather try to make the
scratch less noticeable...

it feels pretty deep but i cant really tell, it mainly took the anti
glare off i think, please help i just want to minimize it if at all
possible
Thanks
Brandon

--
--------------------------------------------------------------
Home Page: http://www.seanet.com/~jasonrnorth

 

[James Sweet]

b w wrote:

Is there any remedy for fixing scratches on big screen tvs? it is a
rear projection tv, the replacement screen is 460 bucks from JVC, i can
just replace that if i need to but i would rather try to make the
scratch less noticeable...

it feels pretty deep but i cant really tell, it mainly took the anti
glare off i think, please help i just want to minimize it if at all
possible
Thanks
Brandon

Some Novus plastic polish might do the trick, but you'll probably have
to polish off the rest of the anti glare coating.

 

[anonymous]

uh, george, are you sure that is not a voltage divider?

George Jetson wrote:

Ken Weitzel <kweitzel@shaw.ca> wrote in news:ibDkh.530079$5R2.359199
@pd7urf3no:



Hi..

http://tpub.com/neets/book7/27m.htm

Ken



Thanks for the info. I tested it, and the tripler is bad. It's shorted
between the primary and the secondary. I'll order a new one and hook it up,
and let everyone in the newsgroup know if it worked. Assuming I don't
electrocute myself.

 

[w9gb]

"Stig Vidar Hovland" <usenet.dr.sv@heime.org> wrote in message
news:soadnaigGc-WJA_YRVnysAA@lyse.net...

I have two APC Back-UPS RS500 units which failed at charging the battery.
It was a capacitor which failed on both of them and I have also found out
that this failure is rather common for this UPS. Here is my description on
how to repair them. If you have a similar problem that the UPS seems to
work OK with a new and charged battery connected, but fails after a short
time (days) with the 'replace battery' light on, then this could help you.

http://www.heime.org/Lists/Posts/Post.aspx?ID=17

Stig Vidar Hovland

Sir -

Did you notice any leakage around the capacitor?
In other words, is this another possible "bad capacitor" fault?
http://www.badcaps.net/
http://news.com.com/PCs+plagued+by+bad+capacitors/2100-1041_3-5942647.html
http://cquirke.mvps.org/badcaps.htm
http://www.pcguide.com/vb/showthread.php?t=25482
http://home.earthlink.net/~doniteli/index27.htm
http://searchwincomputing.techtarget.com/tip/0,289483,sid68_gci1204128,00.html
http://www.geek.com/news/geeknews/2003Feb/bch20030207018535.htm
http://en.wikipedia.org/wiki/Capacitor_plague


w9gb

 

[JANA]

It would be nearly impossible to properly polish out the scratch and not
have any visible damage. When polishing, you will also be removing any
anti-reflective coatings.

There are polishing compounds that will work with Plexiglas, but on most
plastics, they may cause hazing or cloudiness. For an optical surface as
like on a TV screen, this is not practical to polish out. In any case, you
will end up having to replace the screen to fix it properly.

--

JANA
_____


"b w" <aquateenhungerforce1@gmail.com> wrote in message
news:1167242300.839957.249280@a3g2000cwd.googlegroups.com...
Is there any remedy for fixing scratches on big screen tvs? it is a
rear projection tv, the replacement screen is 460 bucks from JVC, i can
just replace that if i need to but i would rather try to make the
scratch less noticeable...

it feels pretty deep but i cant really tell, it mainly took the anti
glare off i think, please help i just want to minimize it if at all
possible
Thanks
Brandon