Toshiba TV29C90 problem; Image fades to black...

J.B. Wood wrote:
On 10/04/2016 06:08 PM, Cursitor Doom wrote:
On Tue, 04 Oct 2016 16:54:42 -0500, Tim Wescott wrote:

So, a customer sent me a board with the query "whuzzup?"

It turns out that there's a resistor in there, which I mostly put in so
that I could monitor current, but I kinda put in as a last-ditch fuse
(1.5 ohm 0603).

On this board, the resistor is open-circuit with no discernible burning.
Is there some electronic mechanism that could cause this? Or am I just
looking at a faulty part?

I assume you've got your test prods directly on the pads so you know it's
not just a dry joint?

X-posted to s.e.r (more appropriate group)


Hello, and the only similar problem I've encountered is with those
sandy-colored dropping resistors (rectangular parallelepiped shaped)
that have been used in radios and TVs. They can swell and/or crack over
a period of time. Repeated heating and cooling no doubt stresses the
resistor material. Sincerely,
Click to expand...

Some of those are 'Fuse Resistors', and are designed to fail open if
the equipment starts drawing too much current, or if it is running too
hot. I replaced hundreds, if not thousands of those in consumer
electronics. Some OEMs switched to the Belfuse 'Chemical Fuses', which
had a chemically coated element that would flash and vaporize the
element at a set temperature.

They were quite common, in spite of Phil Allison's claim to the
contrary.



--
Never piss off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)
 
"Winfield Hill" <hill@rowland.harvard.edu> wrote in message
news:nve4kn0h8m@drn.newsguy.com...
Look165 wrote...

The dissipation power is 200mW max.

Not much safety margin for an 0603.


--
Thanks,
- Win
Click to expand...

Isn't that at 25 °C?
 
On Tuesday, April 10, 2001 at 11:12:06 AM UTC-5, Samantha Lyles wrote:
We recently inherited a few *decades* worth of these schematics from a
television repair shop. They date back to the late fifties, up through the
early eighties. We really have no clue what to do with them and were hoping
this NG might help out with a few leads.

Thanks,

Sam
Click to expand...

do you still have these ?
 
On Thu, 3 Nov 2016 07:58:53 -0700 (PDT), krantrueblood@gmail.com wrote:
On Tuesday, April 10, 2001 at 11:12:06 AM UTC-5, Samantha Lyles wrote:
We recently inherited a few *decades* worth of these schematics from a
television repair shop. They date back to the late fifties, up through the
early eighties. We really have no clue what to do with them and were hoping
this NG might help out with a few leads.

Thanks,

Sam

do you still have these ?
Click to expand...

AFTER FIFTEEN AND A HALF YEARS?? Ya think, Skippy?

Geez, these google groopers!
 
On Sat, 12 Nov 2016 16:56:21 -0500, M Philbrook wrote:

I know some of you work on older PC boards that may have encoder being
stored or operated in damp areas, it tends to cause the solder to
turnish and is hard to rework for repairs..


Other than scrapping it, is there some ready made chemical that will
wash off the surface? Something like s Silver turnish remover?

Would a peroxide and white vinegar do something for me?

Jamie
Click to expand...

X-posted to a more appropriate forum.
 
On Saturday, November 12, 2016 at 6:08:10 PM UTC-5, Cursitor Doom wrote:
On Sat, 12 Nov 2016 16:56:21 -0500, M Philbrook wrote:

I know some of you work on older PC boards that may have encoder being
stored or operated in damp areas, it tends to cause the solder to
turnish and is hard to rework for repairs..


Other than scrapping it, is there some ready made chemical that will
wash off the surface? Something like s Silver turnish remover?

Would a peroxide and white vinegar do something for me?

Jamie

X-posted to a more appropriate forum.
Click to expand...

In the last couple of years I have become addicted to wiping down anything I put the soldering iron to with liquid flux. Solder Wick becomes much more effective and less heat is needed. The only time I don't is if I'm using a vacuum iron because it gums up the works.
 
On 13/11/16 13:21, ohger1s@gmail.com wrote:

In the last couple of years I have become addicted to wiping down
anything I put the soldering iron to with liquid flux. Solder Wick
becomes much more effective and less heat is needed. The only time I
don't is if I'm using a vacuum iron because it gums up the works.
Click to expand...

Normally I give instructables a wide berth for their kids inane content,
but this one seems interesting - and we have plenty of trees around here
with dropped pine cones.

http://www.instructables.com/id/Make-your-own-Eco-friendly-soldering-flux/

--
Adrian C
 
On Monday, November 14, 2016 at 10:02:02 AM UTC-5, John Robertson wrote:
On 201611/13/ 8:10 PM, Sideley wrote:
This newsgroup seems to be deserted. Does anyone can help me to arrange a led array to reduce heat ? I can give further details if someone show up..


You would be better off posting to sci.electronics.repair or .design
(cross-posted).

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
Click to expand...

This, by the way, is the key to using High-output LEDs - heat. They do not generate *much* heat at least as compared to filaments or even CFL lamps - but they generate a great deal of heat per square mm from the actual emitters. Most designs I have seen (Cree, RAB and more) use a heat-sink glue (Thermal Adhesive) on pretty substantial finned heat-sinks. Even my LED Mag-Lite uses a fat heat-sink design on the threaded lamp holder.

Peter Wieck
Melrose Park, PA
 
On 201611/13/ 8:10 PM, Sideley wrote:
This newsgroup seems to be deserted. Does anyone can help me to arrange a led array to reduce heat ? I can give further details if someone show up.
Click to expand...

You would be better off posting to sci.electronics.repair or .design
(cross-posted).

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
 
Op zondag 14 april 2002 10:23:05 UTC-3 schreef Jan Wemmel:
Hi everybody

I need a diode of type MA27A1 but I can't find it anywhere. Is the a similar
type that I can use?

Thanks for your help!!

Jan
Click to expand...

hello can anyone tel me the value of the thermistor ??
 
On Sun, 20 Nov 2016 15:03:44 -0800, shaheedamirkhan wrote:

> hello can anyone tel me the value of the thermistor ??

Sure. 21.2kVA
 
On Sun, 25 Dec 2016 18:44:58 +0000 (UTC), Frank Baron advised:

What does "urging" the clutch pedal mean?
(And what is this "treading" force?)

Everyone with a Toyota-4Runner 3rd-generation manual transmission and
similar Toyota Tundras and Toyota Tacomas has a problem that a certain tiny
plastic bushing invariably fails within a year or three in the clutch pedal
double-helix torsion spring return apparatus.
http://i.cubeupload.com/eXICt7.jpg

The "repair" costs upwards of $150 for parts alone, simply because the
clutch pedal bracket assembly and the pedal itself are usually toast, even
though the three tiny P & Q bushings costs only five bucks each and the
spring itself is only about double that.
http://i.cubeupload.com/54UwZW.jpg

We have already redesigned the clutch pedal return assembly but what we're
now trying to figure out is WHY Toyota used such a complex torsion spring
mechanism when our redesigned linear tension spring seems to work fine.
http://i.cubeupload.com/pSB77I.jpg
http://i.cubeupload.com/8lgaVh.jpg

My problem, right now, is just *understanding* the patent description:
https://www.google.com/patents/US4907468
http://i.cubeupload.com/wYA3iD.jpg

"The present invention relates to an apparatus for reducing the treading
force required to operate a pedal, such as the clutch pedal of an
automobile. More specifically, the present invention relates to an
improvement of the means for urging the pedal."
http://i.cubeupload.com/gMfTU7.jpg

Given they talk about both a two-spring and one-spring setup:
http://i.cubeupload.com/wYA3iD.jpg

But our setup is clearly just one spring:
http://i.cubeupload.com/WYoC8J.jpg

what specifically do you think they mean by "urging" and "treading"?
http://i.cubeupload.com/2Bsddp.gif
Click to expand...

Restating the question to ask if anyone here can tell us what the patent
says about the single-torsion spring setup...

The problem everyone with a clutch has on 3rd-generation Toyota 4Runners,
Tacomas, and Tundras is that the Toyota dealer seems blissfully unaware of
the clutch pedal squeak root cause during the warranty period.
http://i.cubeupload.com/62kbRS.jpg

So the dealers simply grease the $5 nylon P bushing and delron Q bushings,
but by the time the squeak occurs, the $100 clutch pedal P-tab groove is
already starting to be destroyed, eventually taking with it the $100 clutch
pedal bracket holding the two $5 Q bushings.
http://i.cubeupload.com/eXICt7.jpg

So most of us have redesigned the Toyota clutch-pedal return assembly to
remove the extremely complex (geometrically) torsion spring and replace it
with a far simple linear spring setup.
http://i.cubeupload.com/WO7trl.jpg

We've also redesigned the P and Q bushings, using better materials:
http://i.cubeupload.com/UMY0Vl.jpg

But they still fail within two or three years.
http://i.cubeupload.com/UnuX55.jpg

We're currently at the stage of trying to *understand* why Toyota engineers
used such a horrifically complex clutch-pedal-return mechanism, which we
need to know if we're going to assess the long-term impact of our redesign.
http://i.cubeupload.com/Y18Qdh.jpg

We only recently found the patent, which shows a mechanism almost exactly
the same as ours, so, at this point, we're just trying to understand the
patent wording with respect to the single-spring function because we have
been re-designing the single spring setup using a variety of methods:
http://i.cubeupload.com/TYHGRW.jpg

The reason it matters is that the patent shows both a two-spring and a
single-spring mechanism, where we presume the two-spring mechanism operates
in both directions while we can intuit that the single-spring mechanism
operates only in one direction.
http://i.cubeupload.com/wYA3iD.jpg

But is that the case?

We don't know, simply because we don't understand the language of the
patent. https://www.google.com/patents/US4907468

Do you?

Specifically, what is the patent saying the single-spring apparatus
accomplishes?
 
On Sun, 25 Dec 2016 19:19:15 +0000 (UTC), Frank Baron advised:

Specifically, what is the patent saying the single-spring apparatus
accomplishes?

The "treading force" is the pressure exerted on the pedal,
and "urging the pedal" means operating it.
Click to expand...

I wasn't sure if the terms were "directional" since what we're trying to
figure out is why Toyota uses this method, and what the difference is in
the patent description for the two spring method (which we don't have in
our vehicles) and the one spring method (which is what we have).

Since our vehicle diagrams look almost exactly like those in the patent, we
think the rationale as to WHY Toyota used such a complex mechanism will be
described in the patent (if we only understood what the patent says).

Here is our vehicle diagram:
http://i.cubeupload.com/2Bsddp.gif

Here is the patent diagram (which is almost exactly the same):
http://i.cubeupload.com/wYA3iD.jpg

While some of us have re-engineered the bushings, the bushings still fail:
http://i.cubeupload.com/8lgaVh.jpg

Given the re-engineered bushings still fail, most of us have simply
dispensed with the torsion spring altogether, replacing it with a linear
spring instead:
http://i.cubeupload.com/pSB77I.jpg

We've spent some effort on finding just the right geometries for that
linear spring:
http://i.cubeupload.com/FaKA4k.jpg

But, we're really shooting blind if we don't know WHY Toyota used such a
complex torsion spring setup when we know they knew all about the linear
springs (since all the attachment points already exist!).
http://i.cubeupload.com/WO7trl.jpg

Given what you've said, which is that "urging" is merely operating the
pedal, and "treading" is the force applied, then we can convert this quote:
https://www.google.com/patents/US4907468

"The present invention relates to an apparatus for reducing the /treading/
force required to operate a pedal, such as the clutch pedal of an
automobile. More specifically, the present invention relates to an
improvement of the means for /urging/ the pedal."

To this quote:
"The present invention relates to an apparatus for reducing the /amount of/
force required to operate a pedal, such as the clutch pedal of an
automobile. More specifically, the present invention relates to an
improvement of the means for /operating/ the pedal [initially]."

It's important to get the interpretation correct because the pedal has
multiple modes of travel, from the initial pressure to the ending release
to the various points in the arc in between (which the patent discusses in
similarly cryptic engineering terms).

In summary, it seems that the patent mostly refers to the purpose in being
to alleviate STARTING (urging) force - would you concur?
 
In article <0e7c4cd9-5dc1-4e9b-a22a-649f96a2d94c@googlegroups.com>,
pfjw@aol.com says...
Do Not Engage. This is a troll.

Peter Wieck
Melrose Park, PA
Click to expand...

And just when I was going to get my troll Tap hammers out.

Jamie
 
On Friday, June 15, 2001 at 9:37:42 PM UTC-5, Cynthia Criss wrote:
I am trying to find an AT&T 6200 Electronic portable typewriter instruction
manual. Would anyone know a company that could be contacted regarding how
to obtain the instruction manual? I have called every small business
sales or repair company in Reno trying to find one, and so far not one
business has carried this line or services this line.

Thanks!
Click to expand...

I have a manual for Model 6210 if that would help. I also have the typewriter, which usually works beautifully, but it is hanging up sometimes when I turn it on lately, and I can't find out how to get it going again. Would appreciate it if anyone has any ideas.

Thanks.
 
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