Toshiba TV29C90 problem; Image fades to black...

> Tv gives black screen and no sound

It's a Black & White movie which contains no white. As for the sound,
it's close captioned......

 

rickman:

CLOUSEAU'S DEPUTY: Did they know what
kind of a bomb it was?


INSP. CLOUSEAU: The exploding kind!

XD

 

[Dimitrij Klingbeil]

On 23.06.2017 04:15, John Larkin wrote:

Today a couple of guys literally walked up to our place and rang the
doorbell, looking for help. They are medical types who know
basically nothing about electronics.

They want to plop a still image on a PC screen and simultaneously
trigger some external gear. They would like those to be coincident to
within maybe a millisecond. This will be a Windows machine, hardly a
realtime OS. I don't think I could load a screen and simultaneously
bang a serial port pin, or some USB device, accurate to a
millisecond. Well, probably not.
....
Let's say when the image is all on the screen. That suggests that the
optical sensor wins. I guess the video signal sent to the LCD screen,
and the screen refresh, are asynchronous. There is probably a way to
synchronize video ram loads with screen refresh, but I'm not
volunteering to write any device drivers.
....

Hi John

Frankly, I don't think that the various video latencies involved will
give you a 1 ms total timing budget.

Modern LCD monitors are some complex beasts, they generate their own
screen update timing. What you send on the VGA/DVI/HDMI port is no
longer synchronous with the LCD "on the glass" drive signals. Especially
if the input signal is analog (VGA), the monitor will, after digitizing
it, store large chunks and run it through a lot of processing (resize,
anti-alias, filters for various "enhancements" such as edge sharpness)
before buffering the whole frame in order to be able to output it to the
LCD at some potentially unrelated LCD-specific frame rate, which might
not even be publicly documented anywhere.

So you have 2 areas of non-synchronous behavior:
1. in the graphics card (memory write by a driver vs. video output)
2. in the monitor (received video signal vs. LCD panel refresh)

At least Nr. 2 is not under your control, even if you decide to write
drivers, plus as soon as different monitors are used, timing won't be
repeatable any more.

You can use the photodiode trick, but this assumes that the image
arrives at the monitor in whole rather than starting somewhere at a
random line of the screen, progressing to the last line and then
finishing the remaining part from the top. The starting position won't
likely be under your control, as won't be the exact time that the LCD
panel will take to refresh (plus the frame takes longer than 1 ms).

Additionally, the liquid crystals in the LCD itself typically have
longer than 1 ms response times plus the response times are
voltage-dependent (depend on the content of the picture) and asymmetric
(relaxation can be considerably slower than electrostatic alignment), so
going from dark to bright is not the same at going from bright to dark,
and the actual levels (both absolute and relative) of "bright" and of
"dark" also affect timing. The time constants involved are on the order
of single digit ms, but this already eats the 1 ms budget.

Since quantity and series production are both presumably not an issue, a
more likely approach to reach 1 ms timing may be a hardware hack of the
monitor itself. Rather than controlling the content of the video stream
with precision timing (thwarted by monitor buffering and LCD refresh) it
should be much easier to control the LED back light.

LCD TVs, and presumably monitors too, tend to have circuit boards for
power and for video. The power stuff has 2 or 4 layers and cheap PCB
technology as it needs neither BGAs nor controlled impedances, while the
video stuff is more complex and costly per PCB area, so they keep the
area of the video board to the minimum. The drivers for the back light
LEDs tend to be on the power board, not on the video board, and the
connection, again for cost reasons, uses the fewest number of wires
possible. Often, there is only one single wire that controls the LED
state as well as their brightness by using PWM. Hacking a small board
with an AND gate into this circuit as well as some ESD protection for
good measure should be technically possible (as well as a mounting an
SMA jack somewhere).

Whatever generates the timing, could then distribute the same signal to
the new "light enable" port on the monitor and to the other gear.

Dimitrij

P.S. Just recently there was a thread on sci.electronics.repair that
dealt with light-related issues in TVs and hacking them to get the
maximum brightness reduced. Maybe somebody from there can suggest
monitor-related info too.

 

[bitrex]

On 06/24/2017 02:18 PM, Dimitrij Klingbeil wrote:

Whatever generates the timing, could then distribute the same signal to
the new "light enable" port on the monitor and to the other gear.

Dimitrij

P.S. Just recently there was a thread on sci.electronics.repair that
dealt with light-related issues in TVs and hacking them to get the
maximum brightness reduced. Maybe somebody from there can suggest
monitor-related info too.

Killing the backlight is definitely the way to go, but some PC graphics
hardware and monitors have a a one-wire interface routed along with the
display signal for the monitor to report its capabilities to the OS and
for the OS to control the display brightness, independently of the GPU
and display hardware. I'd try to get my hands on one of those and see if
doing it all via software was fast enough before I started hacking into
a monitor!

 

On Monday, July 3, 2000 at 3:00:00 AM UTC-4, Yi-Kuen Lee wrote:

Hi:

I wonder if anybody know where I can buy the light dimmer switch for
the 300 Watt torchiere-style halogen floor lamp. I checked my broken
dimmer switch is Zing Ear ZE-02. I tried to check internet such as
Digikey, Newmark.. But I couldn't find it. And I also find the manufacturer's
homepage: http://www.zingear.com.tw and sent an email to them. They didn't
reply my email. I think they just sell to the big company which makes the lamp.

Yi-Kuen

Hello,

You can buy the switch from this link:
https://www.ceilingfanswitch.com/product/lamp-dimmer-zing-ear-ze-02/

 

On Saturday, 24 June 2017 22:42:57 UTC+1, mikejc...@gmail.com wrote:

On Monday, July 3, 2000 at 3:00:00 AM UTC-4, Yi-Kuen Lee wrote:
Hi:

I wonder if anybody know where I can buy the light dimmer switch for
the 300 Watt torchiere-style halogen floor lamp. I checked my broken
dimmer switch is Zing Ear ZE-02. I tried to check internet such as
Digikey, Newmark.. But I couldn't find it. And I also find the manufacturer's
homepage: http://www.zingear.com.tw and sent an email to them. They didn't
reply my email. I think they just sell to the big company which makes the lamp.

Yi-Kuen

Hello,

You can buy the switch from this link:
https://www.ceilingfanswitch.com/product/lamp-dimmer-zing-ear-ze-02/

Do you reckon it's still awaiting repair after 17 years?


NT

 

Yeah, another Googler. I am oe but I do not drege up decades old posts, I just use it because...

But the thing is you are really not supposed to din halogen lamps because then the halogen is not sufficiently activated to allow the filament to operate in the higher range, which is the whole idea of halogen lamps.

Actually I should have not posted because I do not fucking care.

 

[Phil Allison]

jurb...@gmail.com wrote:

----------------------------

Yeah, another Googler. I am oe but I do not drege up decades old posts,
I just use it because...

But the thing is you are really not supposed to din halogen lamps because
then the halogen is not sufficiently activated to allow the filament to
operate in the higher range, which is the whole idea of halogen lamps.

** Yet another dumb myth trotted out by jurb.

Dimmed halogen bulbs last just fine - stage lighting has used dimmers and halogen lamps together for decades and get expected life out of them.

Hint, when dimmed the filament is cooler and does not NEED the " halogen cycle " to extend its life.


...... Phil

 

[Ian Field]

<jurb6006@gmail.com> wrote in message
news:7de0bee4-da07-4d3c-b325-115fe7c2958c@googlegroups.com...

Yeah, another Googler. I am oe but I do not drege up decades old posts, I
just use it because...

But the thing is you are really not supposed to din halogen lamps because
then the halogen is not sufficiently activated to allow the filament to
operate in the higher range, which is the whole idea of halogen lamps.

Its all about the; "halogen cycle" - vapourised tungsten recirculates and
condenses back on the filament. Under a critical temperature, it deposits on
the inside of the envelope just like regular bulbs.

 

On Sunday, 25 June 2017 22:11:59 UTC+1, Ian Field wrote:

jurb6006@gmail.com> wrote in message
news:7de0bee4-da07-4d3c-b325-115fe7c2958c@googlegroups.com...
Yeah, another Googler. I am oe but I do not drege up decades old posts, I
just use it because...

But the thing is you are really not supposed to din halogen lamps because
then the halogen is not sufficiently activated to allow the filament to
operate in the higher range, which is the whole idea of halogen lamps.

Its all about the; "halogen cycle" - vapourised tungsten recirculates and
condenses back on the filament. Under a critical temperature, it deposits on
the inside of the envelope just like regular bulbs.

but slowly. And when full powered it then cleans itself.


NT

 

[Ian Field]

<tabbypurr@gmail.com> wrote in message
news:c9252c33-28fe-42db-9134-d9326cee2d59@googlegroups.com...

On Sunday, 25 June 2017 22:11:59 UTC+1, Ian Field wrote:
jurb6006@gmail.com> wrote in message
news:7de0bee4-da07-4d3c-b325-115fe7c2958c@googlegroups.com...
Yeah, another Googler. I am oe but I do not drege up decades old posts,
I
just use it because...

But the thing is you are really not supposed to din halogen lamps
because
then the halogen is not sufficiently activated to allow the filament to
operate in the higher range, which is the whole idea of halogen lamps.

Its all about the; "halogen cycle" - vapourised tungsten recirculates and
condenses back on the filament. Under a critical temperature, it deposits
on
the inside of the envelope just like regular bulbs.

but slowly. And when full powered it then cleans itself.

You'd have to get the quartz envelope seriously hot to do that - like
glowing so white it gave off UV.

 

On Monday, 26 June 2017 20:59:17 UTC+1, Ian Field wrote:

tabbypurr> wrote in message
news:c9252c33-28fe-42db-9134-d9326cee2d59@googlegroups.com...
On Sunday, 25 June 2017 22:11:59 UTC+1, Ian Field wrote:
jurb6006@gmail.com> wrote in message
news:7de0bee4-da07-4d3c-b325-115fe7c2958c@googlegroups.com...
Yeah, another Googler. I am oe but I do not drege up decades old posts,
I
just use it because...

But the thing is you are really not supposed to din halogen lamps
because
then the halogen is not sufficiently activated to allow the filament to
operate in the higher range, which is the whole idea of halogen lamps.

Its all about the; "halogen cycle" - vapourised tungsten recirculates and
condenses back on the filament. Under a critical temperature, it deposits
on
the inside of the envelope just like regular bulbs.

but slowly. And when full powered it then cleans itself.

You'd have to get the quartz envelope seriously hot to do that - like
glowing so white it gave off UV.

AIUI they're self cleaning at rated voltage.


NT

 

[John Robertson]

On 2017/06/26 2:18 PM, tabbypurr@gmail.com wrote:

On Monday, 26 June 2017 20:59:17 UTC+1, Ian Field wrote:
tabbypurr> wrote in message
news:c9252c33-28fe-42db-9134-d9326cee2d59@googlegroups.com...
On Sunday, 25 June 2017 22:11:59 UTC+1, Ian Field wrote:
jurb6006@gmail.com> wrote in message
news:7de0bee4-da07-4d3c-b325-115fe7c2958c@googlegroups.com...
Yeah, another Googler. I am oe but I do not drege up decades old posts,
I
just use it because...

But the thing is you are really not supposed to din halogen lamps
because
then the halogen is not sufficiently activated to allow the filament to
operate in the higher range, which is the whole idea of halogen lamps.

Its all about the; "halogen cycle" - vapourised tungsten recirculates and
condenses back on the filament. Under a critical temperature, it deposits
on
the inside of the envelope just like regular bulbs.

but slowly. And when full powered it then cleans itself.

You'd have to get the quartz envelope seriously hot to do that - like
glowing so white it gave off UV.

AIUI they're self cleaning at rated voltage.

When they are RUN at the rated voltage and power. If you dim them the
tungsten is deposited on the quartz and short of heating the quarts to
white hot (above poster's remarks) the tungsten is going to STAY on the
quartz, not recoating on the filament.

http://www.topbulb.com/blog/dimming-alters-halogen-cycle/

In other words don't do it.

John

NT

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

 

[Phil Allison]

John Robertson wrote:

----------------------

When they are RUN at the rated voltage and power. If you dim them the
tungsten is deposited on the quartz and short of heating the quarts to
white hot (above poster's remarks) the tungsten is going to STAY on the
quartz, not recoating on the filament.

http://www.topbulb.com/blog/dimming-alters-halogen-cycle/


** That is merely one person's opinion, not backed up with evidence.

Wiki says differently :

https://en.wikipedia.org/wiki/Halogen_lamp#Effect_of_voltage_on_performance

Stage lighting uses dimming all the time with halogen lamps and there is no blackening or short life experienced - the lamps run much longer as expected.

The claim that the "halogen cycle" puts metal back on the filament is true but it does not deposit it back where it came from so has little effect on lamp life.

Most halogen lamps are low voltage or high powered - so in both cases the filaments are thicker than typical non halogen examples.

Having a thick filament makes a halogen lamp last longer.



..... Phil

 

On Monday, 26 June 2017 23:14:32 UTC+1, John Robertson wrote:

On 2017/06/26 2:18 PM, tabbypurr wrote:
On Monday, 26 June 2017 20:59:17 UTC+1, Ian Field wrote:
tabbypurr> wrote in message
news:c9252c33-28fe-42db-9134-d9326cee2d59@googlegroups.com...
On Sunday, 25 June 2017 22:11:59 UTC+1, Ian Field wrote:
jurb6006@gmail.com> wrote in message
news:7de0bee4-da07-4d3c-b325-115fe7c2958c@googlegroups.com...
Yeah, another Googler. I am oe but I do not drege up decades old posts,
I
just use it because...

But the thing is you are really not supposed to din halogen lamps
because
then the halogen is not sufficiently activated to allow the filament to
operate in the higher range, which is the whole idea of halogen lamps.

Its all about the; "halogen cycle" - vapourised tungsten recirculates and
condenses back on the filament. Under a critical temperature, it deposits
on
the inside of the envelope just like regular bulbs.

but slowly. And when full powered it then cleans itself.

You'd have to get the quartz envelope seriously hot to do that - like
glowing so white it gave off UV.

AIUI they're self cleaning at rated voltage.


When they are RUN at the rated voltage and power. If you dim them the
tungsten is deposited on the quartz and short of heating the quarts to
white hot (above poster's remarks) the tungsten is going to STAY on the
quartz, not recoating on the filament.

http://www.topbulb.com/blog/dimming-alters-halogen-cycle/

In other words don't do it.

John

That may be your belief. IRL halogen stage lighting works just fine.


NT

 

[Phil Allison]

tabb...@gmail.com wrote:

---------------------------

http://www.topbulb.com/blog/dimming-alters-halogen-cycle/

In other words don't do it.

John

That may be your belief. IRL halogen stage lighting works just fine.

** A better example to use is the hundreds of MILLIONS of 12V * halogen down lights* installed in homes - nearly al of which are run on dimmers.

Users get mood light when needed PLSU a *large increase* in life span.

QED.



..... Phil

 

On Sunday, June 25, 2017 at 7:53:16 AM UTC-4, jurb...@gmail.com wrote:
> Yeah, another Googler. I am oe but I do not drege up decades old posts, I just use it because...

Google does display the date
m

 

[Ian Field]

"John Robertson" <spam@flippers.com> wrote in message
news:v7ednesQc4ncGszEnZ2dnUU7-c_NnZ2d@giganews.com...

On 2017/06/26 2:18 PM, tabbypurr@gmail.com wrote:
On Monday, 26 June 2017 20:59:17 UTC+1, Ian Field wrote:
tabbypurr> wrote in message
news:c9252c33-28fe-42db-9134-d9326cee2d59@googlegroups.com...
On Sunday, 25 June 2017 22:11:59 UTC+1, Ian Field wrote:
jurb6006@gmail.com> wrote in message
news:7de0bee4-da07-4d3c-b325-115fe7c2958c@googlegroups.com...
Yeah, another Googler. I am oe but I do not drege up decades old
posts,
I
just use it because...

But the thing is you are really not supposed to din halogen lamps
because
then the halogen is not sufficiently activated to allow the filament
to
operate in the higher range, which is the whole idea of halogen
lamps.

Its all about the; "halogen cycle" - vapourised tungsten recirculates
and
condenses back on the filament. Under a critical temperature, it
deposits
on
the inside of the envelope just like regular bulbs.

but slowly. And when full powered it then cleans itself.

You'd have to get the quartz envelope seriously hot to do that - like
glowing so white it gave off UV.

AIUI they're self cleaning at rated voltage.


When they are RUN at the rated voltage and power. If you dim them the
tungsten is deposited on the quartz and short of heating the quarts to
white hot (above poster's remarks) the tungsten is going to STAY on the
quartz, not recoating on the filament.

http://www.topbulb.com/blog/dimming-alters-halogen-cycle/

In other words don't do it.

I wouldn't go so far as "don't do it" - if you're dimming it, a little
shading probably isn't that much of a problem anyway.

The manufacturers say "don't do it " to cover their asses.

 

[Ian Field]

"Phil Allison" <pallison49@gmail.com> wrote in message
news:8d588b83-7796-47ce-b7c1-0bcc9a4d6adf@googlegroups.com...

John Robertson wrote:

----------------------


When they are RUN at the rated voltage and power. If you dim them the
tungsten is deposited on the quartz and short of heating the quarts to
white hot (above poster's remarks) the tungsten is going to STAY on the
quartz, not recoating on the filament.

http://www.topbulb.com/blog/dimming-alters-halogen-cycle/


** That is merely one person's opinion, not backed up with evidence.

Wiki says differently :

https://en.wikipedia.org/wiki/Halogen_lamp#Effect_of_voltage_on_performance

Stage lighting uses dimming all the time with halogen lamps and there is
no blackening or short life experienced - the lamps run much longer as
expected.

The claim that the "halogen cycle" puts metal back on the filament is true
but it does not deposit it back where it came from so has little effect on
lamp life.

Most halogen lamps are low voltage or high powered - so in both cases the
filaments are thicker than typical non halogen examples.

Wrong - the filament surface get distinctly granular and weak spots are
inevitable. With DC, the tungsten actually migrates along the filament
length - it gets thinner at one end, and guess what happens next.

 

[Ian Field]

<tabbypurr@gmail.com> wrote in message
news:5da4a95e-16e2-4181-a5ae-44dc61d85c11@googlegroups.com...

On Monday, 26 June 2017 23:14:32 UTC+1, John Robertson wrote:
On 2017/06/26 2:18 PM, tabbypurr wrote:
On Monday, 26 June 2017 20:59:17 UTC+1, Ian Field wrote:
tabbypurr> wrote in message
news:c9252c33-28fe-42db-9134-d9326cee2d59@googlegroups.com...
On Sunday, 25 June 2017 22:11:59 UTC+1, Ian Field wrote:
jurb6006@gmail.com> wrote in message
news:7de0bee4-da07-4d3c-b325-115fe7c2958c@googlegroups.com...
Yeah, another Googler. I am oe but I do not drege up decades old
posts,
I
just use it because...

But the thing is you are really not supposed to din halogen lamps
because
then the halogen is not sufficiently activated to allow the
filament to
operate in the higher range, which is the whole idea of halogen
lamps.

Its all about the; "halogen cycle" - vapourised tungsten
recirculates and
condenses back on the filament. Under a critical temperature, it
deposits
on
the inside of the envelope just like regular bulbs.

but slowly. And when full powered it then cleans itself.

You'd have to get the quartz envelope seriously hot to do that - like
glowing so white it gave off UV.

AIUI they're self cleaning at rated voltage.


When they are RUN at the rated voltage and power. If you dim them the
tungsten is deposited on the quartz and short of heating the quarts to
white hot (above poster's remarks) the tungsten is going to STAY on the
quartz, not recoating on the filament.

http://www.topbulb.com/blog/dimming-alters-halogen-cycle/

In other words don't do it.

John

That may be your belief. IRL halogen stage lighting works just fine.

It wouldn't be any surprise if stage lighting is over run for short
periods - filament failure probably makes shading nothing more than a trade
off.