Toshiba TV29C90 problem; Image fades to black...

[Max]

Hello

I see it still appears that no one bothered to plug "MC145145P" into
Google.

If they try, they will find that the IC can be bought at
http://www.rfparts.com/icpll.html

Regards Max

 

[Mike]

undoubtedly resistors changed in value, or caps that went High in ESR, or
leak.

sounds like the caps in the vert output is dried up.

the vertical deflection circuit is usually a single in-line packadge that is
mounted on a heatsink nearby the yoke winding plug-in on the board.

Other things on heatsinks, may be the damper/HOT, regulators.

Usually one large, or two heatsinks in the set.

one has the regulator, one has the HOT, and one has the vert IC. IC has many
pins, HOT only has 3, some regulators only have 3, the ones that have STK,
or STR have many pins.

the vert IC begins in the range of LA, or TDA, or something like that.




"Q.Frost" <qfrost@yahoo.com> wrote in message
news:efc83c6.0307311535.73d26fab@posting.google.com...

Model number is z2411s, inside the back lists the board as a standard
"z" series board for 25 and 27" models. Didn't get the board number.

My problem is this - the screen is approx. letterbox size with lower
edge bright white. I generally work on pinball electronics -
televisions are out of my league, but I got this set free, so...

Is it worth a trip to a repair shop?

Otherwise I'd check it myself for the usual cold soldier joints, caps,
etc., *except* for my great respect of large capacitors, and that
without schematics I don't know where the vertical deflection circuit
is located on the board.

Thanks for your suggestions - I did a quick search here for related
posts, could find anything for this model number.

- Q Frost

 

[james]

When I worked in a TV shop we called those Retrace lines. It's when the
electron beam that scans the image onto the tube gets to the bottom and goes
back up and starts again. On a computer monitor it seems that would be hard
to see. I've seen it on old tv's.
james
(oh, and I would not worry about it until it starts showing all the time)

"Bob Myers" <nospamplease@addressinvalid.com> wrote in message
news:3f29a0aa$1@usenet01.boi.hp.com...

"Luke" <luke_a_p@hotmail.com> wrote in message
news:bgbp72$hq8$1@sparta.btinternet.com...
Yeah it is caused by interference between the pixel grid of the image
and
the dot pitch of the monitor.

No, I'm afraid not. What everyone is missing so far is the
following from the original:


hi,
whenever i bend forward (rather quickly) towards the monitor or
lean
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
back and i'm looking at a fixed point on a white (or otherwise
bright
colour) background, i see vague white diagonal lines sort of
crossing
eachother and converging at the spot i'm looking at. they
disappear
when i stop moving my head.

Moire is NOT going to be affected by the motion of the
observer.

What's happening is simply the fact that if someone moves
quickly enough, such that a CRT monitor screen passes rapidly
through the field of view (and especially if this were going on in a
darkened environment, such that the monitor is the brightest object
in the field), you can see all sorts of such artifacts caused by the
normal raster-scan action of the display. It is perfectly normal,
and nothing to be concerned about.

Bob M.

 

[Sofie]

Q Frost:
Your diagnosis was most likely correct. If you are careful you might be
able to fix this yourself by first going to the website for this newsgroup
at
http://www.repairfaq.org/
Lots of information there including IMPORTANT safety warnings.
Not usually a very expensive repair at a service shop...... if in doubt,
get an estimate first so you can make an intelligent repair decision.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
------------------------------


"Q.Frost" <qfrost@yahoo.com> wrote in message
news:efc83c6.0307311535.73d26fab@posting.google.com...

Model number is z2411s, inside the back lists the board as a standard
"z" series board for 25 and 27" models. Didn't get the board number.

My problem is this - the screen is approx. letterbox size with lower
edge bright white. I generally work on pinball electronics -
televisions are out of my league, but I got this set free, so...

Is it worth a trip to a repair shop?

Otherwise I'd check it myself for the usual cold soldier joints, caps,
etc., *except* for my great respect of large capacitors, and that
without schematics I don't know where the vertical deflection circuit
is located on the board.

Thanks for your suggestions - I did a quick search here for related
posts, could find anything for this model number.

- Q Frost

 

[Mark D. Zacharias]

Sorry, just get a bit weary of the clueless uninitiated who come onto this
group, wanting to know "what always goes wrong" and too cheap to pay to fix
the stuff. They are much more likely to damage the equipment or create a
safety hazard, though the concept of a "Darwin Award Winning Moment" does
appeal to me as it pertains to these people.

Mark Z.


"Rep" <repair_dude@whoever.com> wrote in message
news:74761e73.0307311348.3f9de5a5@posting.google.com...

Message like the one you have below implies that you have way too much
lead in your system! You forgot to include wear a mask, do your
soldering on a ventilated system and wash your hands after.

"Mark D. Zacharias" <mzacharias@nospam.earthlink.net> wrote in message
news:<h__Va.126365$Io.10746851@newsread2.prod.itd.earthlink.net>...
OK, I've been waiting to post this. Here it goes:

First, learn some electronic theory and fundamentals, so that you will
not
injure or kill yourself, and so you will know a bad part when you find
one.
It is critically important to understand theory of operation and
signal-flow
if you are to have any hope of repairing most equipment.
Buy a relatively inexpensive digital multimeter, probably at Radio
Shack.
An oscilloscope would also be most useful; a decent used one can usually
be
found for 100.00 or less.
Learn the appropriate safety considerations for using the tester and
'scope.
There are special considerations for working on most televisions and
other
equipment not using a built-in isolation transformer. Most servicers use
an
isolation transformer for any AC-powered unit under test.
Learn how to use the multimeter to measure resistance, voltage, and
current.
Learn how to use the oscilloscope to observe and analyze waveforms.
Buy a soldering iron, solder, and desoldering equipment.
Learn how to solder and unsolder without damaging the circuit board.
Find a source for replacement parts. Most suppliers have about a 15.00
minimum order.
Order the replacement parts and install them.
Clean the circuit board where you were soldering. Treat the job as if it
were going to be inspected afterwards and graded for neatness.
Visually inspect the piece for any other problems or safety issues.

NOTE:
You are personally responsible for any safety problems you cause, or
those
which you
SHOULD have noticed and failed to correct. So if you work on a TV and it
burns down your friend's house in the middle of the night
because
of something you missed or that you caused, they can sue you, even years
later.
At this point you can just replace a blown fuse, if any, plug the unit
in,
and hope your new parts don't just fail again because you missed
something
or installed a part incorrectly. (Or you could use an AC variac to bring
up
the line voltage slowly while measuring voltages etc. MCM sells one for
90.00)

Check for normal operation. Watch for any signs of overheating, hum,
smoke,
etc and be prepared to shut down quickly.
Test for longer-term operational stability, check for neatness of lead
dress, re-assemble the rest of the way, making sure not to pinch any
wires
etc. Make up your mind to re-assemble the piece exactly as it was. If
there'
s screws left over, you did a sloppy job.
Final test the piece, and satisfy yourself that there is no possibility
of
leakage current between any exposed metal and the AC line. There are
several
ways of doing this. Please refer to the manufacturers' service data or
your
textbooks.

Decide how to politely tell friends, family, freeloaders and cheapskates
that you must charge appropriately for your work.

Welcome to the exciting world of electronics repair.

Mark Z.



"Sofie" <sofie@olypen.com> wrote in message
news:vifo44ljlkra66@corp.supernews.com...
George:
Based on your original posting, a manual and a schematic are NOT going
to
be
much help to you...... it will only be of most use to an experienced
and
knowledgeable tech with the proper test equipment, tools, replacement
parts,
etc. In fact, most techs will repair this kind of problem without
the
manual and schematic.
The Sansui 9090 is a very nice old and powerful receiver and is worth
repairing. Take it to a repair shop BEFORE any failed, botched or
aborted
home repair attempts and at the very least get a repair cost estimate
so
you
can make an INTELLIGENT repair decision with facts instead of internet
guesses.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
-----------------------------------


Today I turned on the Sansui 9090 and the flashing red protector
light
next to
the power button continuously flashed and the stereo never did go
on.
The tuner
seemed to be picking up signals, as evidenced by the signal
meter,
but
the
sound output meters registered zero and no sound came from the
speakers.
Usually
the light flashes red for a few seconds, turns green and then the
tuner
and
stereo activates. Can someone tell me what the cause might be and
if
there is a
simple fix> > I don't have a manual for the unit, and have no idea
what
the protector light is
for. Can someone tell me where to obtain a manual?
Thanks.
George

 

[Dave D]

"cpemma" <cpm@mexbroREMOVE.co.uk> wrote in message
news:bgc0g6$q2v$1@newsg4.svr.pol.co.uk...

A E wrote:
Dave D wrote:


Anyway, the best way to control one of these brushless motors IMO is
a LM317 or similar
regulator with a pot so the OP can set the exact speed he wants. Not
the simplest way but a sure way of getting the speed right.

Simple enough, though. 5 parts, and we can all agree on that! (input
cap, LM317, output cap, resistor, pot) This is more complex than
required. Maybe the OP can just remove half the fan's blades
instead...

Snag with 317 is that 1.5-2v loss; better method with a 0.75v loss and 3-4
parts ;-)

http://www.cpemma.co.uk/ef.html

Alternatively the TL431 adjustable zener driving a pass transistor. (The TL
431- aren't they a great little device ;-))

Dave

 

[Engineer]

Lenny wrote:

My son who works with me in my electronics service business is
presently enrolled in an Electronics Technology course at the local
College. I introduced him to test equipment by getting him a used 260
and a new cheapo hand held digital from Harbor Freight, just so that
he could "get his feet wet". He's a hard worker, and a good boy and
now I would like to do something special for him. He has asked for a
Fluke portable meter with a case for his birthday. Although I own
older model Fluke and HP bench meters, I rarely have a need for them
in my work so with the large selection of new Fluke portables
available frankly I'm stumped as the what is the best deal on a decent
service meter for the money. Thanks for any advice. Lenny Stein.

I am very happy with the Fluke 111 I use at home. I have no
affiliation with Fluke but we do use them at the lab.

Cheers,

Roger
--
Roger Jones, P.Eng.
Thornhill, Ontario,
Canada.

"Friends don't let friends vote Liberal"

 

[TV Fixer1]

I'm not familiar with that particular set, but with a tube that big, there
should be some sort of adjustment for the set's orientation to the Earth's
magnetic field, similar to the ones used on Mistubishi, RCA, etc. Also, check
and make sure there isn't a metal pipe in the wall behind the set.

 

[~^Johnny^~]

All I do is throw another log on the fire!

Tompall Glaser fan?
--
-john


~~~~~~~~
"The first step in intelligent tinkering is to
save all the parts." - Aldo Leopold
~~~~~~~~

 

[Bob Minchin]

Rewar wrote:

Hello

I have an old (1985) DVM which has the ribbon cable for the LCD bonded in some
way to the PCB. Well, that's not quite right - it was bonded but has come
loose. I was thinking of making a thick mixture of Al glitter and epoxy to
rebond it. Unfortunately, this would be a one chance try since if it doesn't
work there would be no way to salvage the cable for another try.

My question - Is there some kind of conductive glue or other bonding agent
which would do the job?

Thanks

Robert

Use silver loaded paint for the conductive part then an epoxy or other method for
mechanical stength.

I've found in the past that adding metal power to glue does not conduct as each
metal particle get insulated from it's neighbour by the glue.

regards

Bob

 

[Cathy Stevenson]

In article <dbfce1c0.0308010425.15c8a302@posting.google.com>, David
Lubich <davidlubich@hotmail.com> wrote:

Hello Group
My G3 Powerbook (bronze keyboard, 400MHz) no longer recognizes any
Firewire devices connected to it or even the CD-ROM drive. Even worse,
the trackpad has stopped working: thankfully, it still recognises USB
devices, so I can at least control it with a mouse.
These problems built up over a month - first the CD-ROM, then the
Firewire, then the trackpad - so I'm hoping that it's a software
problem.
Any help would be hugely appreciated.
Thanks
David

What have you tried so far? Have you run any disk utilities - Disk
Warrior, Norton, e.g.? Does it happen with extensions off?

Which version of the MacOS are you using?

Any recent changes to the PB - especially addition of RAM?

More info would be helpful-

Cathy

--
"there's a dance or two in the old dame yet." - mehitabel

C.Stevenson, M.D.
cats1921@sonic.net

 

[DaveC]

On Fri, 1 Aug 2003 8:26:10 -0700, Bob Minchin wrote
(in message <3F2A8691.674CA0C6@ntlworld.com&gt:

Rewar wrote:

Hello

I have an old (1985) DVM which has the ribbon cable for the LCD bonded in
some
way to the PCB. Well, that's not quite right - it was bonded but has come
loose. I was thinking of making a thick mixture of Al glitter and epoxy to
rebond it. Unfortunately, this would be a one chance try since if it
doesn't
work there would be no way to salvage the cable for another try.

My question - Is there some kind of conductive glue or other bonding agent
which would do the job?

Thanks

Robert

Use silver loaded paint for the conductive part then an epoxy or other
method for mechanical stength.

Where can "silver-loaded paint" be bought? Or do you do the loading yourself?

Thanks,
--
Dave C
dave-usenet3016@mailblocks.com

 

[Bob Minchin]

DaveC wrote:

On Fri, 1 Aug 2003 8:26:10 -0700, Bob Minchin wrote
(in message <3F2A8691.674CA0C6@ntlworld.com&gt:

Rewar wrote:

Hello

I have an old (1985) DVM which has the ribbon cable for the LCD bonded in
some
way to the PCB. Well, that's not quite right - it was bonded but has come
loose. I was thinking of making a thick mixture of Al glitter and epoxy to
rebond it. Unfortunately, this would be a one chance try since if it
doesn't
work there would be no way to salvage the cable for another try.

My question - Is there some kind of conductive glue or other bonding agent
which would do the job?

Thanks

Robert

Use silver loaded paint for the conductive part then an epoxy or other
method for mechanical stength.

Where can "silver-loaded paint" be bought? Or do you do the loading yourself?

Thanks,
--
Dave C
dave-usenet3016@mailblocks.com

Hi Dave,

Here in UK it is readily available from electronic distributors. I'm not very
familiar with US suppliers - perhaps Radioshack?

To give you and idea of what is available, look at http://rswww.com and search for
the seven digit part numbers below

186-3593 Adhesive, conductive paint, silver loaded
186-3600 Adhesive, electrically conductive paint, silver loaded
298-7757 Paint, conductive, flexible, pen
101-5621 Paint, silver conductive, bottle, 3g
321-7295 Pen, conductive paint, PCB, repair, Circuit Works, std tip, 8.5g

Hope this helps

Bob in UK

 

[Patch]

"Amateur Electrician" <ae@com.net> wrote in message
news:bgefgb$lhf$1@slb6.atl.mindspring.net...

I bought an antique desk fan that unfortunately has a problem - it only
runs at
top speed. The motor is Century model 37, and it says that it is 32 VDC
(although I plug it directly into 115 VAC?). When I diassembled the
control,
there was only a flimsy wire being rolled around two pieces of plastic,
which
seemed to absolutely no effect. The resistance of the motor is 16 ohms,
and
the fan runs at about 1A AC.

Sensing that the way to slow down the motor is have a higher impedance, I
played around with putting in a resistor and then a capacitor and see what
happens! Well, calculating a net impedance of 115 ohm at virtually all
inductance, I put in a high power resistor to cut the current in half.
The
motor would not start (although, obviously the resistor got pretty hot!)
I
then tried a capacitor to get the impedance to 115 ohm in the other phase,
calculating that I needed around a 10 microfarad capacitor. This did not
slow
down the fan, but it did blow the 450 V rated capacitor!

Sensing that I should inductive impedance, and since I own a few
electromechanical pibnall machines and had a few relay coils handy, I used
a
few. As if by cosmic coincident, the drop in current to .8 & .6 (using 2)
gave
exactly the correct lower speeds I was looking for. However, these coils
got
very hot, and in any case they seem to be set up for the 54 VAC of the
pinball
machine (Bally, 70's)

Anyway, what is the solution to my dilemna? Is there anywhere I could buy
inductors to work here? Am I correct in assuming that the 115 ohm
impedance is
inductance in nature, and that current attenutation is achieved by adding
some
inductance in the circuit? Where can I get such an inductance component -
especially one that does give off as much heat!

Thanx

If the motor says it is a DC type, why are you putting 110 AC on it?

 

[Dave D]

"DaveC" <dave-usenet3016@mailblocks.com> wrote in message
news:0001HW.BB4FFBAB00219698F0386600@news.individual.net...

Where can "silver-loaded paint" be bought? Or do you do the loading
yourself?

Your local car parts shop should have it, ask for rear demister repair
paint. It's not cheap though.

Dave

 

[G. Skiffington]

Thanks all for the helpful info.......Seems that RF Parts is going to be
the source. No further info needed.


73 - Gord

 

[Charles Schuler]

It is irrelevant why we have emotions. We have them, and there is not
much we can do about them. If something feels good we do it, taking into
account, if that makes someone else feel too bad, you might suffer net
harm from the coinsequences.

Kevin, you shot your own foot off with the above. That's the very point
that some other posters, including myself, have been trying to make. There
are a bunch of questions that are "irrelevant" to physics. The big one is
"What was it like before the big bang that created the universe?" There is
no way that any form of physics can deal with that question because there is
no way to use the scientific method to approach it. Singularities are an
enigma to the scientific method. That's the way it is, and ... I'll go way
the hell out on the skinny limbs here ... that's the way it's always going
to be.

There is no reason to invoke God at this point or to try to convert you to
some more conventional mode or method or paradigm or philosophy. It would
just be so nice to hear you say that science has limits. Science is simply
something conceived by man and it's not so terrible to peek under the
academic robes of science and see the scrawny legs of man. In fact, it's
damned healthy. Students of science are taught to be skeptical so why not
be skeptical about Mother Science Herself?

 

[Amateur Electrician]

I bought an antique desk fan that unfortunately has a problem - it only
runs at
top speed. The motor is Century model 37, and it says that it is 32 VDC
(although I plug it directly into 115 VAC?).

If the motor says it is a DC type, why are you putting 110 AC on it?

Because that is the way that the manufacturer did it. It is set up for the
standard 115 VAC, but the motor says "Direct Current" on it.

 

[Kevin Aylward]

Charles Schuler wrote:

It is irrelevant why we have emotions. We have them, and there is not
much we can do about them. If something feels good we do it, taking
into account, if that makes someone else feel too bad, you might
suffer net harm from the coinsequences.

Kevin, you shot your own foot off with the above.

Oh. Why?

That's the very
point that some other posters, including myself, have been trying to
make. There are a bunch of questions that are "irrelevant" to
physics. The big one is "What was it like before the big bang that
created the universe?" There is no way that any form of physics can
deal with that question because there is no way to use the scientific
method to approach it. Singularities are an enigma to the scientific
method.

Before the big bang is still an open question. Physics may well find a
method to deal with it. The postulated singularity is held by many to be
a limit of *classical* GR. It is held that a correct *Quantum*, theory
of gravity will remove this issue. Indeed, there is work on M-Branes
that take one prior to the supposed singularity.

That's the way it is, and ... I'll go way the hell out on
the skinny limbs here ... that's the way it's always going to be.

There is no reason to invoke God at this point or to try to convert
you to some more conventional mode or method or paradigm or
philosophy. It would just be so nice to hear you say that science
has limits.

It doesn't. By definition.

Science is simply something conceived by man and it's
not so terrible to peek under the academic robes of science and see
the scrawny legs of man. In fact, it's damned healthy. Students of
science are taught to be skeptical so why not be skeptical about
Mother Science Herself?

Science is a tautology. Science is about *any* consistent set of
knowledge, i.e. non self contradictory knowledge. One goal of science is
to reduce the basics of this knowledge to the simplest possible. If one
notes Goedal, that any complete system has true, but unprovable
statements, one can see how science includes any consistent set of
knowledge.

Example. The basics of quantum mechanics has some simple postulates.
e.g. Description in a Hilbert space by operators, eigen value equations
etc. However, this in not sufficient to fully explain all of QM.
Additional axioms are required, e.g. the Pauli exclusion principle.
Given an incomplete scientific explanation, additional information is
added to complete it. There is no reason that this new information
should be explainable by the existing knowledge.

Now, suppose some new information is required to explain behaviour,
consistent with or included in a general way in QM, but such that QM is
insufficient to resolve the outcome in detail. If we discover a new,
consistent principle that explains this behaviour, this new behaviour,
is simply added to the set of science.

I think the issue is that you are maybe not really clear on that science
is really about.

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.

 

An old vacuum I have is rated at 120VAC or 80VDC, quite odd, but if
they say so...
On 2 Aug 2003 04:15:08 GMT, ae@com.net (Amateur Electrician) wrote:

I bought an antique desk fan that unfortunately has a problem - it only
runs at
top speed. The motor is Century model 37, and it says that it is 32 VDC
(although I plug it directly into 115 VAC?).

If the motor says it is a DC type, why are you putting 110 AC on it?


Because that is the way that the manufacturer did it. It is set up for the
standard 115 VAC, but the motor says "Direct Current" on it.