Toshiba TV29C90 problem; Image fades to black...

[Wayne Tiffany]

Does anyone have a case sitting around that would fit this model? I was
given one that the front shell and board supts are busted up. The back is
fine, though. I have a KV27S15, but the cases are too different to make it
work. The TV appears to work as long as you hold everything so it doesn't
touch.

I am in the Kansas City, MO area. Thanks.

WT

 

[Charles]

"Blattus Slafaly" <boobooililililil@roadrunner.com> wrote in message
news:CImdnTNmqeA-3VTVnZ2dnUVZ_qzinZ2d@giganews.com...

faiz wrote:
The are some good reasons to put home Security System.....

Please visit:


http://wireless-security-alarms.blogspot.com/2008/09/there-are-some-good-reasons-to-put-in.html


Thank You,

Nobody is safe. Alarms just make you feel good. A lock only keeps out
honest people. Today's burglar don't care if you are home or not, if you
are he might hack you with a machete .

Safety is an illusion.

faiz is perhaps abusing this forum. However, security systems do add a
level of deterrence/protection. Something as basic as a motion detecting
outside light will help in those cases where the prowlers are not targeting
a given residence. Many prowlers pick the easy targets and any deterrent
can be worthwhile.

Absolute safety is indeed an illusion, but increased safety is easily
achieved.

 

[William Sommerwerck]

"Dave" <dspear99ca@yahoo.com> wrote in message
newsbayk.2231$yS5.534@edtnps83...

"don ward" <dward7@earthlink.net> wrote in message
news:dward7-9A74AE.21552210092008@earthlink.vsrv-sjc.supernews.net...
In article <r41yk.22177$89.13971@nlpi069.nbdc.sbc.com>,
Tiger Luck <Tiger_Luck@natures_preserve.afr> wrote:

Every piece of gear I have that has + and - power buss has the
positive rail cap with the + to the rail and the - lead to ground.
HOWEVER the negative rail has the - to the rail and the + to
ground.
Things are not always as they seem
dnw

Then you must not have any pieces of gear that are in working order. On
the
negative rail, the - lead of the cap is on the rail and the + lead is to
ground. Can't be any other way.

As I read it, that's what he said.

 

[William Sommerwerck]

I was partly right once, so perhaps the luck (ahem) will continue.

Barring a bad part, it sounds -- as someone else suggested -- that there's
something wrong with the board, or a solder joint.

Lemme tell you a story...

Back in 1980, I assembled an Integrex kit and had problems with one of the
op amps overheating. I spend almost an hour checking voltages, resistances,
etc, trying to figure out exactly what was causing the problem.

It then occurred to me to turn the board over and look carefully. Viola! Two
traces had a solder bridge. (Integrex was cheap and didn't provide a solder
mask.)

 

[William Sommerwerck]

"Dave Plowman (News)" <dave@davenoise.co.uk> wrote in message
news:4fdd3688bfdave@davenoise.co.uk...

In article <d20dc45v099rscl6l107ddqrq57lag9umf@4ax.com>,
Ardent <iam@here.com.invalid> wrote:

Someone plugged my Dream machine (rated 110 VAC) into a 220
VAC outlet and the transformer primary got trashed. Since I will be
living here for a while I thought of getting a transformer made here
locally (very cheap, honest).

I'm willing to bet it's rather more than just the transformer. Copper
takes time to melt while solid state destructs near instantly.

Agreed. The fact the transformer was damaged -- which likely doesn't occur
instantly -- suggests that at least a few parts in the power supply let out
their life-giving smoke.

 

[William Sommerwerck]

You are ignoring core saturation. That limits the maximum voltage
on the secondary.

But wouldn't that require enough current draw to saturate? Or are you
arguing that the transformer is so cheap that it normally operates close to
saturation, anyway?

 

[William Sommerwerck]

I've been at this thing for about four days straight now and
I am totally fried behind it. I've resurrected stuff the local
vintage stereo store has given up on, but this took me to
my limits and left me out to dry.

Be patient. Put the unit aside for few days and come back to it. Don't
expect to solve every problem instantly. When your mind is fresh again,
you're likely to figure it out.

 

[Arfa Daily]

<friedfam5@aol.com> wrote in message
news:7634ff0f-fff2-404c-a89c-3c4cf008c070@k37g2000hsf.googlegroups.com...

I tried to put in new ink cartridges and didn't have the machine on
the correct setting and it refuses to work now. Any ideas?

Epson ? Throw it. Replace with an HP ...

Arfa

 

[Mark D. Zacharias]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:f_ednZrs7sceI1TVnZ2dnUVZ_t_inZ2d@comcast.com...

"Dave Plowman (News)" <dave@davenoise.co.uk> wrote in message
news:4fdd3688bfdave@davenoise.co.uk...
In article <d20dc45v099rscl6l107ddqrq57lag9umf@4ax.com>,
Ardent <iam@here.com.invalid> wrote:

Someone plugged my Dream machine (rated 110 VAC) into a 220
VAC outlet and the transformer primary got trashed. Since I will be
living here for a while I thought of getting a transformer made here
locally (very cheap, honest).

I'm willing to bet it's rather more than just the transformer. Copper
takes time to melt while solid state destructs near instantly.

Agreed. The fact the transformer was damaged -- which likely doesn't occur
instantly -- suggests that at least a few parts in the power supply let
out
their life-giving smoke.

I see small transformers like this fry very quickly with double voltage
applied. Happens all the time here in the US when the neutral lifts. Most
often that is all that is wrong, though I'll admit that does sound
surprising.

Mark Z.

 

[Arfa Daily]

<snip>

Output trannies are back in. Speakers hooked up. Tuner tuned in.

Fingers crossed.

And here goes... power up... power down, got smoke.

Output trannies on the left side got hot, but held.

The drama continues. Will pull output trannies on left side and check
right side for okayness.

Spoke too soon. Three of the output trannies fried and the fourth probably
would have if I had left the power on longer.

I have never given up on a piece of gear until now. It almost seems like
the power supply might be the problem seeing as how the outputs on both
channels fried, but who knows. It reads okay.

I've been at this thing for about four days straight now and I am totally
fried behind it. I've resurrected stuff the local vintage stereo store has
given up on, but this took me to my limits and left me out to dry.

If anyone wants this pup, with schematics, minus a couple of output
trannies, for the price of postage, email me at <jack6128 at gmail dot
com

Je suis fini.


--
Einstein forgot to carry the two

I do sympathise old boy. In years past, I never gave up on anything either,
but I must admit that these days, sometimes I do, out of both a need to be
commercial and keep the wife off my back for not earning any money, and out
of sheer frustration. I think that latter condition is something that creeps
up on you with age. Suddenly, some things are more important than not
letting some inanimate object beat you ...

That said, I reckon that this baby has got to be worth one more go if - and
*only* if - you can lay hands on a variac, so you can wind up the input
power to make the rails just high enough to take sensible measurements, but
low enough to stop the ouput trannies releasing their magic smoke ...

As William says, give it a break over the weekend, then come back to it with
fresh eyes (and a variac !!) on Monday. If you do, carry on keeping us
updated. It's an interesting saga, if a little frustrating for you.

Arfa

 

[William Sommerwerck]

I do sympathise old boy. In years past, I never gave up on anything
either,
but I must admit that these days, sometimes I do, out of both a need to be
commercial and keep the wife off my back for not earning any money, and
out of sheer frustration. I think that latter condition is something that
creeps
up on you with age. Suddenly, some things are more important than not
letting some inanimate object beat you ...

That said, I reckon that this baby has got to be worth one more go if -
and
*only* if - you can lay hands on a Variac, so you can wind up the input
power to make the rails just high enough to take sensible measurements,
but low enough to stop the ouput trannies releasing their magic smoke ...

As William says, give it a break over the weekend, then come back to it
with fresh eyes (and a Variac !!) on Monday. If you do, carry on keeping
us updated. It's an interesting saga, if a little frustrating for you.

One of the reasons I've enjoyed helping is that you've explained exactly
what you've done, which makes the process fun -- and educational, too!

PS: I have several working Advents. Let me know if you want me to check the
voltages on a "good" one. I'm willing to do it "live", in real time, if we
can find a time suitable for both of us.

 

[Arfa Daily]

"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:wdOdnWuMEaW3zlTVnZ2dnUVZ_v7inZ2d@earthlink.com...

"Dave Plowman (News)" wrote:

In article <d20dc45v099rscl6l107ddqrq57lag9umf@4ax.com>,
Ardent <iam@here.com.invalid> wrote:
Someone plugged my Dream machine (rated 110 VAC) into a 220 VAC outlet
and the transformer primary got trashed. Since I will be living here
for a while I thought of getting a transformer made here locally (very
cheap, honest).

I'm willing to bet it's rather more than just the transformer. Copper
takes time to melt while solid state destructs near instantly.


You are ignoring core saturation. That limits the maximum voltage on
the secondary. I have replaced several 120 VAC transformers that opened
when plugged into 240 VAC and had no problems with the electronics. You
aren't always lucky, but if it is a typical cheap as possible
transformer it will die first.

I reckon you've been lucky then Michael. Living here in a 240v country, I
see several pieces of kit a year that have either come over from the states
with their owners to live here, or have been brought back here by UK holiday
makers, picking up that 'deal of the century' at Walmart. Almost always,
although agreed not *always* always, in my experience, the damage which
ensues from plugging these 120v transformer based items into 240v line
power, is not limited to just the transformer primary winding failing.

However, I have seen more than a few which have had a perfectly conventional
glass fuse in the primary, which has failed violently, but has managed to
protect both the transformer, and the following circuitry ...

Arfa

 

[geoff]

stratus46@yahoo.com wrote:

Tiger Luck wrote:
snip
The grounds are intact. By that I mean to say that point in the CB
where
electrolytic caps C312 and C313 are grounded is continuous with the
ground at the
power supply filter caps. Chassis is the same. All points which are
supposed to be
grounded are continuous as read by an ohm meter.

Those little 100uF caps are _not_ the main 'lytics. The mains would
likely be 1000uF to 10000uF (or possibly even more) and be located
near the main bridge rectifier - which is on the _rest_ of the
schematic along with the power transformer.. I think you'll find the
main negative bus 'lytic to be open or dried out so that you're
putting LOTS of ripple current on those littlle 100uF caps. Those
100uF caps are just local 'clean up' caps and can't handle the load.

Also could be crook bridge rectifier, and the caps are being pumped up by
half-wave surges rather that continuous full wave ones, so the average
charging current is higher.

geoff

 

[Graz]

On Thu, 11 Sep 2008 20:15:08 GMT, Archon <Chipbee40_SpamNo@yahoo.com>
wrote:

Archon wrote:
Hi , any TV repair folks help out here.

This widescreen TV had a flashover, took out the red output on the
TDA6108JF Video Output Amp on the crt board.

I bought replacement chip and fitted it, now instead of a bright red
screen with flyback lines I get a very bright white screen reduced in
size with flyback lines.

Previously I had Vin of 2.8Vdc, Vout(Cathode) 139Vdc on the dud chip
(remaining working parts)
Now I have 0.8Vdc input and 18Vdc output (Cathodes)

Black current measurement output pin 5 old chip 0.8Vdc, new chip 7.5Vdc

I don't have a schematic, any ideas where to buy ? I'm not in the TV
servicing business anymore, prefer watching them than fixing them but
this is my own TV and I guess I have to fix the sucker.

I don't see any adjustments in this set, is there anything I need to do
to set up/ recalibrate the black level? Isn't this automatic on these
fangled new sets? Is the new chip duff? It did arrive in a polybag,
guess its not that static sensitive. Nothing else reads as out of spec
and using the duff chip, disabling the red output and shorting the red
and green cathodes at the tube gives a reasonable picture.

TIA for any help,

JC
OK, No matter, fixed it, new chip was duff, wtf, lucky I ordered 2.

Are duff chips a common problem? I recently bought a frame output
chip for a Hitachi TV that was shorted across two pins.

 

[Dave Plowman (News)]

In article <e9rjc4l7kdnnjmbtonbkib6m1t3hic3082@4ax.com>,
Ross Herbert <rherber1@bigpond.net.au> wrote:

What you need to remember is that both ends of the wireless link need to
be powered from the mains supply.

Not really - the power they consume is well within reason for batteries.
Although it wouldn't make sense to not mains power the transmitter. And
having to mains power the receiver/speaker sort of negates the whole idea
- you might as well just run a cabled extension speaker.

--
*He who laughs last, thinks slowest.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[Dave Plowman (News)]

In article <e9rjc4l7kdnnjmbtonbkib6m1t3hic3082@4ax.com>,
Ross Herbert <rherber1@bigpond.net.au> wrote:

What you need to remember is that both ends of the wireless link need to
be powered from the mains supply.

Not really - the power they consume is well within reason for batteries.
Although it wouldn't make sense to not mains power the transmitter. And
having to mains power the receiver/speaker sort of negates the whole idea
- you might as well just run a cabled extension speaker.

--
*He who laughs last, thinks slowest.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[Dave Plowman (News)]

In article <e9rjc4l7kdnnjmbtonbkib6m1t3hic3082@4ax.com>,
Ross Herbert <rherber1@bigpond.net.au> wrote:

What you need to remember is that both ends of the wireless link need to
be powered from the mains supply.

Not really - the power they consume is well within reason for batteries.
Although it wouldn't make sense to not mains power the transmitter. And
having to mains power the receiver/speaker sort of negates the whole idea
- you might as well just run a cabled extension speaker.

--
*He who laughs last, thinks slowest.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[Arfa Daily]

"Josh9.0" <squalene9er@hotmail.com> wrote in message
news:edc27e17-c81c-4894-a43c-19f2e908ef3f@2g2000hsn.googlegroups.com...

On Sep 11, 12:12 am, Geo <hw9j-s...@dea.spamcon.org> wrote:
On Wed, 10 Sep 2008 09:58:27 +0100, "Arfa Daily"
arfa.da...@ntlworld.com
wrote:

However, I don't think that he has the necessary professional
background in service, to be able to run down a problem like this by
disconnecting things, and running alternate grounds ... :-\

Reminds me of an on-site repair job at a Scottish University (on a DVM).
The Phd
looking over my shoulder at the circuit points to the 1uF capacitor in
the
integrator section and says that will be the problem.
I went for the 10M resistor rather than the polypropylene cap...

Geo

Please tell me more, elaborate. This is interesting

I would suggest that he is talking theory vs practical knowledge. Given the
same situation, where an integrator was formed from a polyprop cap and a 10M
resistor, I too would go for the resistor every time over the cap, because
years of experience tells me that resistors over about 470k are far more
likely to go high / open, even in non-stress situations, than that type of
cap is to go faulty in any way ...

It is this type of understanding of the fundamentals of servicing, that I
was referring to when I made the comment about disconnecting and subbing
grounds. The fact that the Phd picked the cap over the resistor shows that
he understood the theory of the circuit involved, so was in the right area,
but did not have the required practical experience to know that the cap,
even though it's the more complex device, was probably a hundredth as likely
as the high value resistor, to be at fault.

Arfa

 

[William Sommerwerck]

It's unlikely that Sony will sell parts, or even a service
manual for something as inexpensive as a clock radio.

Of course they will. But this radio is old enough (I assume) that Sony no
longer stocks parts for it. The manual is probably still available, but it's
likely you'll pay a lot for a photocopy.

Businesses (in general) seem to be increasingly less worried about breaking
the laws that require them to stock service parts.

 

[Dave Plowman (News)]

In article <ufWdnSrFx4k701fVnZ2dnUVZ_q_inZ2d@comcast.com>,
William Sommerwerck <grizzledgeezer@comcast.net> wrote:

It's unlikely that Sony will sell parts, or even a service
manual for something as inexpensive as a clock radio.

Of course they will. But this radio is old enough (I assume) that Sony
no longer stocks parts for it. The manual is probably still available,
but it's likely you'll pay a lot for a photocopy.

Businesses (in general) seem to be increasingly less worried about
breaking the laws that require them to stock service parts.

In the UK it's common to get long warranties on quite low price things - a
3 year one on a 20 quid cordless drill. But they don't repair them if they
go wrong - just give you a like for like replacement or your money back.
Perhaps that's why such things cost about twice as much as in the US. ;-)

--
*I must always remember that I'm unique, just like everyone else. *

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.