Toshiba TV29C90 problem; Image fades to black...

[Richard Crowley]

"Don Pearce" wrote ...

Yes, but there is an important difference - the FM signal drops into noise
gracefully and slowly. That DAB signal is only 1dB or so bigger than one
that is not received at all, and 1dB bigger again would be received
cleanly.

That is a general problem with ALL digital communication,
it has a much different degradation behavior.

 

[DaveM]

"Dave" <dspear99ca@yahoo.com> wrote in message news:25sfk.370$Ou3.88@edtnps82...

"Dave" <dspear99ca@yahoo.com> wrote in message
news:W2sfk.369$Ou3.337@edtnps82...
I've found one source (in Europe) for these transistors, but they're asking
$20 each for them and I am concerned about counterfeits.



Make that 20 Euro, so $32/ea.

Consolidated Electronics Inc. is a US company, but they list stock for both
devices.
http://www.ceitron.com/semi/semi.phtml?part=2SA1065 ($4.00 US) and
http://www.ceitron.com/semi/semi.phtml?part=2SD2489 ($11.95 US).
Can't vouch for authenticity... but I've used CEI for several years and have had
no problems with counterfeits.

Contact info:
Toll Free: 1-800-543-3568
scoy@ceitron.com

Consolidated Electronics
P.O. Box 20070
Dayton, Ohio 45420
USA

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Experience: What you get when you don't get what you want

 

[Trevor Wilson]

"Meat Plow" <meat@petitmorte.net> wrote in message
news:21ieo3.10l.19.5@news.alt.net...

How the hell do they make an LED so damn bright?

**Modern white LEDs can manage around 100 - 120 Lumens/Watt. This is more
than 4 times the figure attainable by halogens (incandescent). It rivals
fluorescents and is catching up to halide discharge lamps (the kind fitted
to high end autos). Unfortunately, LEDs suffer from the same thermal
constraints applicable to all silicon and silicon-like devices. Maximum chip
temperatures are limited to around 175oC. Halogens and discharge lamps are
not so constrained. Bulb temperatures can be MUCH higher. They can,
therefore, occupy less space than LEDs, since LEDs require substantial heat
sinking.

Moral: If you think LED torches are bright, have a look at a halide torch.


--
Trevor Wilson
www.rageaudio.com.au

 

[William Sommerwerck]

Interesting many tapes are charged so the adhesive stays on.

I'm not sure I follow...

 

[William Sommerwerck]

1. UV LED exciting special fluorescent white material.

I've never heard of UV LEDs. They're not impossible, but they'd require a
rather wide band gap.

My understanding was that white LEDs were blue LEDs with a
yellow-fluorescing material. (blue+yellow=white -- to the eye)

 

[Steve]

alphamnemonic <shmotmail@gmail.com> wrote in
news:7817733e-cd3d-4f3d-9e6e-3b63791ab1af@d45g2000hsc.googlegroups.com:

On Jul 14, 4:50 pm, Steve <nob...@nobody.com> wrote:
alphamnemonic <shmotm...@gmail.com> wrote
innews:e7294911-213d-4734-b0cd-
3386568e81a2@y38g2000hsy.googlegroups.com:





On Jul 7, 6:09 pm, Steve <nob...@nobody.com> wrote:
Steve <nob...@nobody.com> wrote
innews:Xns9AD0CDEF8F97Fnobodynobodycom@21
6.196.97.136:

alphamnemonic <shmotm...@gmail.com> wrote in
news:ba29f199-331f-48c1-ab96-28c3a81d42d8

@i18g2000prn.googlegroups.com:

On Jul 2, 6:20�pm, Steve <nob...@nobody.com> wrote:
s...@ece.drexel.edu wrote in news:16ea6110-be19-4a21-aecc-
10780259c...@e39g2000hsf.googlegroups.com:

On Jul 2, 3:35 pm, alphamnemonic <shmotm...@gmail.com
wrote:
Hi Everybody

This chip normally puts out square pulses. In the power
supply I am working on
(http://www.laserfaq.org/sam/150rcsch.pdf) it
is putting out a sawtooth wave. I am testing it in 'standby
mode', in which Q4 is off and R33 is in control of the duty
cycle. Replacing the IC1 has no effect. Does anyone have
any ideas?

Where are you seeing sawtooths? �Pin 13?

--- sam | Sci.Electronics.Repair
FAQ:http://www.repairfaq.org/ �Repair | Main Table of
Contents:http://www.repairfaq.or
g/R
EPAIR/
+Lasers | Sam's Laser
FAQ:http://www.repairfaq.org/sam/lasersam.htm��
ďż˝ ďż˝ | Mirror
Sites:http://www.repairfaq.org/REPAIR/F_mirror
.html

Important: Anything sent to the email address in the message
header above is
ignored unless my full name AND either lasers or electronics
is included in the
subject line. �Or, you can contact me via the Feedback F
orm
 in the
FAQs.

That is my question. Why do you have output A and output B
(pin 11 and 14
)
grounded?

Also, pin 13 is VC in for the transistor collectors. Why do
you have this connected as an output?- Hide quoted text -

- Show quoted text -

Yes the sawtooth is on pin 13. Pin 13 is being used as an
output and pins 11 and 14 are grounded because the chip is
being used in single- ended supply mode (see

http://www.datasheetcatalog.org/datasheet/motorola/SG3525AN.pdfp.
6
for an example of this configuration). I can see why you find
that strange--I did too!

I'd avoid the funky setup you have. In my opinion I'd connect
pin 13 and 15 together and use either output A or B.

I'm not sure what Q4 is doing, I've never seen it used this way,
but you must know more than me since you designed this elaborte
circuit.

Keep us posted at what you do to resolve the problem.

I have been looking at the circuit and the datasheet.

I'm willing to bet the schematic is drawn wrong. It doesn't make
any sense to have pin 13 driving the base of a transistor.- Hide
quoted text
-

- Show quoted text -

The schematic is drawn correctly. This mode of operation is
described on p.6 of the datasheet (link is given in my post from
July 3). I removed the board and re-soldered R1 and R2, and the
supply is now working properly again. A rather boring fix, but if
it works long term I won't complain... If anyone else is having
trouble with this supply, I can send you waveforms captured with
FlukeView from the working unit. Thanks for the suggestions
everyone.

I'd like to see them. Do you have them in a format you can easily
email?-
Hide quoted text -

- Show quoted text -

Yes: .rtf

I phrased that incorrectly.

I meant can you post them on here for downloading or on a site?


Thanks

 

[Jim Yanik]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in
news:JeydnSX7Xe-TE-PVnZ2dnUVZ_v_inZ2d@comcast.com:

1. UV LED exciting special fluorescent white material.

I've never heard of UV LEDs. They're not impossible, but they'd require a
rather wide band gap.

My understanding was that white LEDs were blue LEDs with a
yellow-fluorescing material. (blue+yellow=white -- to the eye)

http://www.nichia.com/product/led-lamp-uv.html

http://www.theledlight.com/UV.html

--
Jim Yanik
jyanik
at
kua.net

 

[William Sommerwerck]

"Jim Yanik" <jyanik@abuse.gov> wrote in message
news:Xns9ADDCFEA6AF87jyanikkuanet@64.209.0.87...

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in
news:JeydnSX7Xe-TE-PVnZ2dnUVZ_v_inZ2d@comcast.com:

1. UV LED exciting special fluorescent white material.

I've never heard of UV LEDs. They're not impossible, but they'd require
a
rather wide band gap.

My understanding was that white LEDs were blue LEDs with a
yellow-fluorescing material. (blue+yellow=white -- to the eye)

http://www.nichia.com/product/led-lamp-uv.html
http://www.theledlight.com/UV.html

Fascinating. Thank you.

I'm sure they're popular among geologists, among others...

 

[Arfa Daily]

"hr(bob) hofmann@att.net" <hrhofmann@att.net> wrote in message
news:ff277a08-22b4-4a07-a1ca-d33166deadab@59g2000hsb.googlegroups.com...
On Jul 16, 4:55 pm, Bill <bb...@comcast.net> wrote:

Franc Zabkar wrote:
On Wed, 16 Jul 2008 08:48:29 -0700, "Nicole Bischoff"
pa...@paigedwinter.com> put finger to keyboard and composed:

Richard the St00pid Bullis says so on 24hoursupport.helpdesk.

A coil holds no charge. A capacitor does. However a coil's back emf
may belt you if you interrupt its current flow.

- Franc Zabkar

If the set is on and you are playing near the CRT you will get zapped
from the CRT and not the coil. If it is off you can get nailed by the 25
KV of the anode capacitance which can be there for days. I got knocked
across the room once by a hand to foot discharge, some people get killed
by it, and I now put my elbow on the chassis so only my arm gets hit, a
big ouch but not dangerous except to your arm and finger nerves.
Always discharge high voltage. I got nailed by a 2,000 volt capacitor on
a microwave that had been off for 3 days, less voltage but a big uF cap.
Bill Baka

Don't just discharge the anode one time, do it once, wait about 20
seconds and do a second discharge. There is a phenomenon that I can't
recall where the charge is stored partially in the glass envelope and
the voltage can rebuild up to a few kV after the initial discharge
unless the initial short lasts for several seconds.

Bob Hofmann


I was taught that it is because the area of the effective capacitor formed
by the internal anode coating, the glass, and the external coating, is so
large compared to the single small discharge point, that much of the
residual charge sort of 'rushes away' as far as it can to try to re-eqaulise
itself into an evenly distributed high voltage. Then, over a couple of
minutes, it spreads out again over the whole internal surface of the tube.
If you discharge over a couple of minutes with a resistive probe, you don't
get a problem.

Back in the days, I had an old anode lead cut from a scrap FBT, that fed
into a small plastic box that had a number of 10k resistors in it, in series
to up the overall voltage rating of them. Coming out of the other end, was a
lead with a croc clip on it. You used to just hook this to the external
coating grounding spring, and then plug the cavity connector into the tube.
Then go for a cup of coffee. When you came back, the tube could then be
dealt with in complete safety, including removing it for replacement.

Arfa

 

[Dave Plowman (News)]

In article <g5lue4$970$1@aioe.org>,
Curtis Brown <pryce@stripperweb.com> wrote:

3. Can anyone recommend a source for NOS Jap transistors that sells
these?

Why don't you try rephrasing that question you racist cock-suck.

Is it racist to refer to me as a Scot since I'm from Scotland? Call me
Dave when I was christened David? Call someone Tex?

--
*It is wrong to ever split an infinitive *

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

 

[GregS]

In article <2faf26c3-dfaf-4121-8006-72182a654ba3@8g2000hse.googlegroups.com>, "Jerry G." <jerryg50@hotmail.com> wrote:

I have used black electrical tape. I start by partialy covering the
sensor window, and increasing how much it is covered to reduce the
sensitivity.

Jerry G.


On Jul 15, 12:43=A0am, Father Guido <F...@no.where> wrote:
I have an IR operated garbage can, trouble is the sensor is too
sensitive and it opens whenever you walk by. How can I reduce the
sensitivity of the IR receiver so I have to put my hand very close to
the sensor before the lid opens?

We used to use exposed Kodachrome. Got any bad old slides ??

greg

 

[Trevor Wilson]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:JeydnSX7Xe-TE-PVnZ2dnUVZ_v_inZ2d@comcast.com...

1. UV LED exciting special fluorescent white material.

I've never heard of UV LEDs. They're not impossible, but they'd require a
rather wide band gap.

**They've been around for quite some time. They're not quite UV, in the
sense that a fluoro is, but they still produce significant UV output. I've
used them in place of expensive (and virtually unobtainable) miniature cold
cathode UV tubes.


--
Trevor Wilson
www.rageaudio.com.au

 

[Steve]

alphamnemonic <shmotmail@gmail.com> wrote in
news:20f3161b-2cd5-4d14-b547-3571a53fdb50@z6g2000pre.googlegroups.com:

On Jul 17, 11:08 am, "Michael A. Terrell" <mike.terr...@earthlink.net
wrote:
alphamnemonic wrote:

I don't have a website, but I will post them here if you tell me
how.

   This isn't a binary newsgroup, and you can't post pictures through
Google Groups.

   Sign up for a free photo hosting service and post the link to the
pictures.

--http://improve-usenet.org/index.html

If you have broadband, your ISP may have a NNTP news server included
in your account:http://www.usenettools.net/ISP.htm

Sporadic E is the Earth's aluminum foil beanie for the 'global
warming' sheep.

The pics are up at
http://sites.google.com/site/scientificelectronicsrepair/

Those are interesting waveforms.

Nothing I would have expected if I was working on this or I didn't have a
known working unit for comparision.

 

[Arfa Daily]

"Meat Plow" <meat@petitmorte.net> wrote in message
news:21ieo3.10l.19.5@news.alt.net...

How the hell do they make an LED so damn bright?

Meat ! I'm surprised someone as experienced as you has to ask that !
Everyone knows that they do it by packing the magic smoke in UNDER PRESSURE
.... !!

Arfa

 

[Barry & Nikki]

If more than 30 years old I'd try a newer model; say that is only 10-25
years old. They can usually be controlled with a little less cash and they
are a little easier to clean up and present. Not to mention how well they
make you feel when you get them to work once the lights are out.



"Dillo" <test@celbridgegolfsociety.com> wrote in message
news:dac0d993-3ea5-4c95-9a43-2815e76057b4@e39g2000hsf.googlegroups.com...
> I have an ir controlled wife. It doesnt work

 

[Arfa Daily]

"Meat Plow" <meat@petitmorte.net> wrote in message
news:21n7a6.vns.19.4@news.alt.net...

On Fri, 18 Jul 2008 09:31:20 +0100, Arfa Daily wrote:


"Meat Plow" <meat@petitmorte.net> wrote in message
news:21ieo3.10l.19.5@news.alt.net...
How the hell do they make an LED so damn bright?

Meat ! I'm surprised someone as experienced as you has to ask that !
Everyone knows that they do it by packing the magic smoke in UNDER
PRESSURE ... !!


Yeh silly me heh. There are actually a couple things left that I still
don't know

Hundreds I don't, mate !! I went in my friend's shop today and he said
"Hey, waddya know ?" I told him "Everything about nothing, or nothing
about everything, take your pick"

Arfa

 

[N_Cook]

Chuck B. <ReplyTo@Thread.thx> wrote in message
news:g1c184hciccig65h5bup3osqvhjs41eiut@4ax.com...

We are having a problem with our over the air reception. During
nighttime hours the reception is great, but poor during daylight
hours. Is this normal?

I get the same effect, sometime I must get up on the roof and put up a yagi
with better, ie reduced rearward lobe/ higher forward lobe responses.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

 

[New Jersey]

I can not say for sure but there is station that they must
change direction of antennas from night to day or wise versa
because of signal propagation which interfere with other networks
FCC regulation sorry KA2AYS



"N_Cook" <diverse@tcp.co.uk> wrote in message
news:g5sd40$2j9$1@registered.motzarella.org...

Chuck B. <ReplyTo@Thread.thx> wrote in message
news:g1c184hciccig65h5bup3osqvhjs41eiut@4ax.com...
We are having a problem with our over the air reception. During
nighttime hours the reception is great, but poor during daylight
hours. Is this normal?

I get the same effect, sometime I must get up on the roof and put up a
yagi
with better, ie reduced rearward lobe/ higher forward lobe responses.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

 

[New Jersey]

have tried aluminum or stainless foil/tape

"Father Guido" <FG@no.where> wrote in message
news:rcn2845vak3uh6snd89pugdd2nmlhf57p4@4ax.com...

I've tried various amounts of scotch tape, but just putting the tape
over the sensor activates it, and it never resets. I.e. I turned the
device off, placed tape over sensor in varying levels and positions
but when I turn the device on, it opens and refuses to close. Sigh.

I look at some of the other suggestions, thanks for your help!

Norm

 

[Mike S]

<Mikespo@webtv.net> wrote in message
news:27632-487EEE14-1922@storefull-3272.bay.webtv.net...

I recently inherited a Hitachi VT-UX 627A and for the life of me can't
figure out how the cover can be removed so I can clean the heads. I
removed the one visible screw that secures the lid but it won't budge
and I don't want to force it. Called Hitachi and they wouldn't tell me!

On other manufacturer's VCRs I've owned and successfully cleaned, the
top was easily removable. Just a matter of removing the screws and
sliding it off. Hoping some of the wizards in this group can help.
Thanks.

Two screws on the bottom near the outer edges toward the sides