Toshiba TV29C90 problem; Image fades to black...

[Cassie Carstens]

The "Everyday Practical Electronics" of april 2003 has a circuit of a
three-state vehicle probe on page 282.

Cassie

 

[John Del]

Subject: Re: Lightning strike to JVC AV-36260
From: Chris Henderson

Just a tad more info. I've callled to have JVC come warranty it if
possible and have looked into most of my options w/out having to shuck
out a chunk of change. But, my original question was, I guess, does
anyone have any ideas as to what I may be looking at cost for repair?

The factor I look for is whether there is any damage to the cold side of the
power supply. If the damage is limited to the hot side, it's under $150
complete, and there should be no issues of performance or reliability. If
there is damage on the cold side (especially foil damage), I wouldn't suggest
repairing it.
John Del
Wolcott, CT

"Nothing is so opportune for tyrants as a people tired of its liberty."
Alan Keyes

(remove S for email reply)

 

[DigitalVinyl]

jerryg50@hotmail.com (Jerry Greenberg) wrote:

Going from experience with these TV sets, I would suspect the problem
to be mainly localized to the power supply. I would first try to
service the power supply. If the problem in the supply is really very
severe, then I would probably replace the complete supply circuit
board.

The tv service guy said he had to order the power supply board--it
needed to be replaced. Sounds like the latter case .

Until he gets that component in, he can't tell if there is any further
damage.

Most of the time when there is an overvoltage on the AC mains to a TV
set, only some localized components in the supply have to be replaced.
The rest of the set should not have any effect at all.

The only time I have seen a set have to be scrapped due to a voltage
problem was when a lightning strike went directly to the antenna, and
did a lot of damage.


Jerry Greenberg
Thanks.

DiGiTAL_ViNYL (no email)

 

[Nigel]

Don't switch it on again until you have had it repaired.


"verzub" <verzub@nospam.net> wrote in message
news:N7MOa.7063$Vx2.3326328@newssvr28.news.prodigy.com...

I have a Toshiba TV made in '91 and the whole image is squished into one
horizontal line. Does anyone know what I could do?

 

[DigitalVinyl]

"David" <dkuhajda@locl.net.spam> wrote:

You should have virtually no chance of any future problems, especially if
they can replace the power supply board with a new one from Sony.
Well I guess I'll have to ask for proof that they used new parts and

not refurbished parts.

Sony sets use a switch mode power supply that has tons of protection built
in. In fact many techs have a difficult time with the XBR Sony sets for
that very reason, in the past it was difficult to know which protect circuit
was causing the problem.

Usually 220volts on a modern SMPS only damage a very small number of
components. They are designed to be within normal operating range between
90 and 150 volts at a minimum, many are dual system capable 90 volts through
260v AC.

The only exception is if the set was turned on and running and he lifted the
nuetral line while the 220v was applied.
The TV wasn't on but they are always on a little (mmeory, clock,

infrared). 4 out of 5 pieces of equipment that was fried was "off" at
the time.

Oddly enough the 2 guys doing the work were taking too long. after not
having power for six+ hours a "foreman" came back on site and expected
them to be finished by that time. They started turning the power on
but the homeowner noted one guy was still banging the copper
rods(grounds?) into the ground outside and the power was on. He
assumes the ground wasn't connected at that point.

There could be further damage in
the set and the SONY authorized SELECT servicer should have no trouble
identifying that.
I'm hoping lots is damaged or the picture tube is shot. I would trust

a new tv from a factory but a refurbished one that has been yutzed
with but god knows who, with parts from god knows where, is not what I
paid for. Everytime you bring something in for maintenance or repair
it is an opportunity for a different problem to be introduced. Anyone
who's expereinced NOT having a reliable mechanic knows that.

David
THanks.

DigitalVinyl <reader@internet.com> wrote in message
news:6b1pgvsneh0j038vq46c2po8otfdbgdjnc@4ax.com...
I have a high end Sony XBR HDTV. An electrician's employee fried it
when working on replaceing the panels. We think they sent 220v through
two different circuits. A fan, vcr, dvd, two light bulbs, and a surge
suppressor protecting computer equipment were all fried.

The TV was the big ticket item ($2,000+ to replace), it was only 11
months old and has worked flawlessly.

The repair guy assured me once the "broken" boards are replaced it
will be fine. I have no faith that when the TV repair guy is done that
I will have a "good as new" tv. I fully expect the TV to fail within
the next few years or suffer from other issues. If the voltage got
past the power board I don't see how they could know if it caused
subtle damge to the components or picture tube that could shorten its
life.

We've all dealt with lemons. Once something needs repairing, a
lifetime of repair can follow. I thought I scored a good one that
would last 10-20 years. Now I will have a refurbished TV.

Am i way off base here--from a TV-electronics view? I don't want to
be contacting this electrician and arguing whether future problems are
a result of this incident?

I really want them to replace it with a brand new one.

I've dealt with heat damaged high-end computers that have taken up to
two years to detect all the subtle damage to circuitry. The servers
were flaky and constantly replacing components. Two years after the
initial damage the manufacturer found tiny cracks and leakage in
circuit boards.

DiGiTAL_ViNYL (no email)

DiGiTAL_ViNYL (no email)

 

[Sam Goldwasser]

DigitalVinyl <reader@internet.com> writes:

"David" <dkuhajda@locl.net.spam> wrote:

You should have virtually no chance of any future problems, especially if
they can replace the power supply board with a new one from Sony.

Well I guess I'll have to ask for proof that they used new parts and
not refurbished parts.

Perhaps irrelevant. If repaired properly, a "refurbished" part may be
more reliable than a new one since most of its individual components have
survived the infant mortality period.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: The email address in this message header may no longer work. To
contact me, please use the Feedback Form at repairfaq.org. Thanks.

 

[Rufus V. Smith]

"Swizzle" <kenyon@returnwarehouse.com> wrote in message
news:Iu9Pa.28189$rh3.15807@fe14.atl2.webusenet.com...

We recently purchased a lot of Nintendo Gamecubes and a lot are giving us
disc read errors. The system will boot up, disc spins, and the laser moves
and then the Gamecube will either say that there is no disc in the
machine,
or that the disc can not be read. Does anyone have any suggestions or
information on this problem? I've already cleaned the lense so it's not
just dust.

Bill

Was this an eBay-type "lot" of Gamecubes. Is this perhaps why they were
on sale? I think you've got an alignment problem or electronic problem.

Are you equipped to handle electronic issues or are you armed with just
a screwdriver and a package of lense cloths?

I've never opened one, but if possible (connectorized) I'd be inclined to
do the "field-service swap" and swap "known good" components until
it worked. Then you'd know what works and what doesn't. If you can't
repair them all, maybe you can mix and match parts to cobble together
good units out of several bad ones.

Rufus





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[Sam Goldwasser]

DigitalVinyl <reader@internet.com> writes:

jerryg50@hotmail.com (Jerry Greenberg) wrote:

Going from experience with these TV sets, I would suspect the problem
to be mainly localized to the power supply. I would first try to
service the power supply. If the problem in the supply is really very
severe, then I would probably replace the complete supply circuit
board.

The tv service guy said he had to order the power supply board--it
needed to be replaced. Sounds like the latter case .

Until he gets that component in, he can't tell if there is any further
damage.

Could you realistically expect more? There's no way to test the rest of
the set without the power supply. It doesn't imply anything.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: The email address in this message header may no longer work. To
contact me, please use the Feedback Form at repairfaq.org. Thanks.

 

[Dave Widgery]

"William R. Walsh" <newsgroups1@idontwantjunqueemail.walshcomptech.com>
wrote in message news:Cx5Pa.22830$Ph3.764@sccrnsc04...

Hi!

Thanks William and Sam for not quacking with the flock.

I posted a question out of curiosity and amazement at the lack of
protection. I did not know I was poking a stick into a clump of
maggots who are in love with HP and take me for a fool.

Unfortunately, I think many of the people in this group get a little too
carried away. Every last one of them has doubtlessly burned something up
in
a fit of foolishness. For professional repairpeople, some sure lose their
professional side here.

If you get into repairing electronics, you will see plenty of STUPID
designs. Get ready, you may see things that are far more shocking.

If the thread got carried away, it was primarily due to the wording of the

original post, whether intentional or not and I suspect written while you
angry at both yourself for making such a stupid mistake (I have also made
them in the past) and HP for not incorporating a simple component that would
have stopped you doing any damage, the post also came over as a direct
attack on HP for not having the foresight that you might make this mistake,
therefore it was their fault, you also went on to say that you would not
even consider replacing it with another HP because of this, even though the
chances are that an Epson or Lexmark may well have the same problem.

Maybe if you had waited to calm down and worded a less aggressive post that
described your experience and opinions in a more rational way, you may have
had much more constructive and less critical thread. (This could also apply
to some of the people responding as well, possibly myself included).

What's the most stupid thing that I have done? I switched on a Tanberg
terminal that was connected to 220v but set to 110v, the cover was off at
the time, there was a big cloud of smoke and a capacitor made one hell of a
bang, the can put a large dent in the ceiling tile before ending up 30ft
across the room, it scared the hell out of me, luckily replacing the
capacitor and a burnt resistor fixed it again.

Dave

 

[EBG]

What is the light source in this thing? Is there a part number anyone has?

If I can get this top "lid" off maybe I can see it.


"Hellraiser" <hellraiser1.nospam@blueyonder.co.uk> wrote in message
news:behrb3$58chp$1@ID-166521.news.dfncis.de...

Perhaps there is a problem with the scanning light not being on?

Hellraiser.........
"EBG" <maberger@comcast.net> wrote in message
news:CsCdnTCaDaTK8pGiXTWJjg@comcast.com...
What's up with a Canon faxphone B640 that will not send or do a copy of
anyhting without the image being ALL black?

Not a negative of the image......just all black.

Never did this before, does it on everything I try.

THANKS very much for any help.

 

[Kevin Carney]

I try to do the same (posting repair tips). I've benefited from others, so
why not help others.

--
change .combo to .com for correct email

***************************************************
"We ought always to know precisely why a given job
is done in a particular way, and why it is done at
all, and why it can't be done more efficiently,
if it must be done at all."-- T.J.Watson

***************************************************

"david" <texas@houston.rr.com> wrote in message
news:157d51fa.0307091155.a227818@posting.google.com...

James-
My Viewsonic GS815 had the exact same problem.
Per your advice, I replaced the 4N35 and it's fixed. I'll post
another message with "GS815" in the title so others can search on this
history and benefit from the generic solution with some Viewsonics

thanks a million for the great detective work.
-dave

 

[Sofie]

What are you planning to use it for?
Just wondering..... thanks!!
---------------------------


"Steve and Stef" <slnixon@earthlink.net> wrote in message
news:jJaPa.39362$C83.3129239@newsread1.prod.itd.earthlink.net...

Just wondering.... thanks!!

 

[Rich]

"Dave D" wrote in

It's impractical to replace the ckt board and cost from HP is
higher
than a new printer. Does anyone one have a rational explanation
why
devices that use external power adapter would not be reverse
polarity
protected.

Rich, do you have the original supply and what is wrong with it?

Yes I do, somewhere in the pile. There was no voltage out of it.
Might even be a broken wire, right at the plug. Had a pair of
headphones, where that happened recently with hardly any use.

As this thread lives on, I'm tempted to slice it apart. For one, to
see how sophisticated it is and two, what really failed. In
retrospect, had I done that I might have fixed it. But on more than
one occasion I wasted lots of time investigating and still ended up
spending the money for a new part.

Regards,

Rich

 

[paul s]

Steve Tremblay wrote:

Hello All.

I search a schematic for FM transmitter. I want connect the unit to my
Dishnet to listen the music on garden. I need about 250 - 500 feets, with
Stereo features

Thats a bloody huge garden. For the average sized garden however have a look
at:

http://www.the-gadgeteer.com/irock-review.html
Ready made, and pocket-sized, $30.
--
Paul S

 

[Rich]

"Dave Widgery" wrote in

If the thread got carried away, it was primarily due to the wording
of the
original post, whether intentional or not and I suspect written
while you
angry at both yourself for making such a stupid mistake (I have also
made
them in the past) and HP for not incorporating a simple component
that would
have stopped you doing any damage

Yes to both. I'm the OP.

the post also came over as a direct attack on HP for not having the
foresight that you might make this mistake, therefore it was their

fault

You read it as an attack on HP. I call it an "actual example on
hand". I listed a specific model, for a good reason.

I had no other devices to use as examples for that specific question.
That was the whole purpose of posting it here, where people do open
cases with warning labels on them They also have the knowledge,
and I was hoping brand impartiality, to comment on what they see these
days.

you also went on to say that you would not even consider replacing
it with another HP because of this, even though the chances are that

an Epson or Lexmark may well have the same problem.

Yes, this part was gratuitous and should not have been posted. It
ended up being the unintended focus of the thread for some responders.
I evaluate every product on its own merits, the best way I can, and do
not hold "forever" grudges )

Rich

 

[Kevin Aylward]

N. Thornton wrote:

Hi


Thats right. Yet it is tried all the time by those who
a) dont know the causes
b) haven't gone and found out what works.

And just how do you propose one finds out the cause without doing
experiments?
And just how do you propose one finds out what works without doing
experiments?


That's not so hard.

First, 'find out what works without doing experiments':

Many people have tried to treat their depression in many ways.
Many
have failed, some have succeeded. Thus many experiemnts have been done
already.

But completely ad-hoc in general, therefore of limited use.

All one need do is collect the data:
1. realise this is an effective way to learn successful methods
2. attract the people
3. assess the claimed results
4. Apply statistics to discover what is actually working.

Then we will know what works.

But you can't apply meaningful statistics to back of the envelope
studies. One needs controlled studies, double-blind tests etc...
etc....Anything else is, in reality pretty much useless. Its simply not
cricket to recommend, in a professional clinical environment, quack
cures based on dubious anecdotal claims.

Now, about 'find out the cause without doing experiments':

The prime point here is we primarily need to know what works. Whether
you also know the cause or not, what works will still work.

I agree that what works can a valid approach in some instances, in that
the reason behind is not always necessary. However, you have no idea
what *really* works without doing proper studies.

Looking at the cause can come later, for now we just want to know
what's working so we can apply it.

Its a bit like this: you can plant your wheat seeds and get a crop, or
you can sit around and worry about what causes it to grow. Its the
result that matters most.

And the side effects.

This is something I think our NHS health service needs to learn. There
are folk around who have solved many problems successfully,

Says who?. The snake oil salesman?

lots of
doctors and nurses have come across the odd one who achieved a
remarkable result with their condition.

Which could have been luck, i.e. nothing to do with any purported cure,
just fixed itself on its own. Happens all the time.

Yet the NHS is failing to
collate and assess such data, and study known successes to learn more
techniques it can apply.

One offs are not success. The evidence has to be very strong. This can
*only* come about by controlled trials. This is really a no-brainier.

Instead the NHS refuses to learn what it
doesn't know.

Confirmation of claimed cures involve large amounts of money. The system
don't have it.

Its like a river bed, among all the dirt there is gold
and diamonds, and those valuable things are simply not being made any
use of.

I think you bit out on this one. The risks of doing something wrong
simply does not allow for this approach. There are too many claimed
cures that arnt. Without proper studies, its all meaningless. One only
has two say the words "law" "sue" to put most people in the picture.


Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

 

[LASERandDVDfan]

Are you equipped to handle electronic issues or are you armed with just
a screwdriver and a package of lense cloths?

He will not be able to disassemble any of his Gamecubes. All Gamecube consoles
use security screws with the outer housing which require a special bit to
unfasten. These are available for sale from many reputable service supply
sources, though. - Reinhart

 

[Sam Goldwasser]

"Dave D" <someone@somewhere.com> writes:

Did you open up the printer to see what was damaged? It would be very ironic
if it turned out to be simply a diode wired across the supply to prevent
reverse polarity! I would open it up and see what's up. I doubt you've fried
the logic ICs as there'll be some kind of 5v regulator, which shouldn't pass
any voltage in reverse polarity conditions. It won't hurt to take a peek,
seeing as how it's dead anyway.

That's a really good suggestion. It would be ironic if after all this,
the component that smoked was a resistor acting as a fuse in series with
the DC which had a protection diode across it!

Or, some eletrolytic capacitors were given reverse polarity and
let their smoke out with no damage elsewhere.

One should never assume that *ALL* the magic smoke escapes with a single
screwup.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: The email address in this message header may no longer work. To
contact me, please use the Feedback Form at repairfaq.org. Thanks.

 

[Rich]

Hi Dave,

You're making me go back to the crime scene

----- Original Message -----

Did you open up the printer to see what was damaged? It would be
very ironic
if it turned out to be simply a diode wired across the supply to
prevent
reverse polarity! I would open it up and see what's up. I doubt
you've fried
the logic ICs as there'll be some kind of 5v regulator, which
shouldn't pass
any voltage in reverse polarity conditions. It won't hurt to take a
peek,
seeing as how it's dead anyway.

Yes I took it part, while I could still smell it. Not even sure I
could put it back together now

The part that's clearly "well done" is a square IC with P/N SC79199FN.
It appears to be Motorola part. It has 11 pins on each side. The
middle 4 pins on the top (if you orient the IC to read the numbers),
are where the action was.

Rich

 

[Peter Gottlieb]

Duh, what do you *think* he wants to use it for?


"Sofie" <sofie@olypen.com> wrote in message
news:vgqsr81uho3e23@corp.supernews.com...

What are you planning to use it for?
Just wondering..... thanks!!
---------------------------


"Steve and Stef" <slnixon@earthlink.net> wrote in message
news:jJaPa.39362$C83.3129239@newsread1.prod.itd.earthlink.net...
Just wondering.... thanks!!