Toshiba TV29C90 problem; Image fades to black...

[NSM]

"Tom MacIntyre" <tom__macintyre@hotmail.com> wrote in message
news:d4e7o010kbo00gdrbf337mflgheearg7jr@4ax.com...
| On Thu, 28 Oct 2004 06:39:24 GMT, "Fred"
| <testing@testing1212mouse.com> wrote:
|
| >I'm just wondering... if you call this up and get some gal jabbering in
| >Chinese at you, how do you know she's not just complaining about you not
| >mowing the lawn or fixing that leaky kitchen faucet -- like you hear at
| >home?
|
| Too true...I once heard of a short play/skit where a man and a woman
| sat on a sofa side by side speaking seemingly seductive French to each
| other, in front of an English audience, and the script was basically a
| grocery list.

It's an old music hall bit. They are actually reading the ingredients -
listed in French - from the side of a bottle of HP sauce.

N

 

[Joe Bramblett, KD5NRH]

"Michael A. Covington" <look@ai.uga.edu.for.address> wrote in
news:414a2466$1@mustang.speedfactory.net:

Assuming it's a CRT, indeed, it could be the video signal levels.
Look for a switch that selects the signal level.

Any idea where this would be on a Gateway EV910?

It could also be a problem with the high voltage circuit.

Anything in particular to check?

As a quick fix, IF YOU KNOW HOW TO WORK WITH HIGH VOLTAGE CIRCUITS,
there is generally an internal brightness setting.

Are you referring to the screen bias, or is there something else I should
be looking at?

The monitor was a freebie, but it's bigger than my current crop, so I'd
like to get it working. From what the previous owner said, it had to be at
100% brightness to look right when he got it, and it kept going downhill
over the course of about a year. Adjusting the bias got it readable, but
it's still noticeably dark.

I'm used to dealing with HV circuits in older TVs, but they didn't tend to
pack things in so tightly, so it was easy to trace out a circuit to find
the problem.

 

[Mark D. Zacharias]

...defiantly appreciated

LOL!

Mark Z.

(try MCM at 1-800-543-4330, talk to a product support person, see if they
can help you.)

"Mike" <ifix4you@hotmail.com> wrote in message
news:219a69ce.0410300641.18efc7ec@posting.google.com...

Looking for schematic for discontinued item:
Tenma Oscilloscope Model #: 72-3060
Any help would be defiantly appreciated.
Thank you for your time.

Mike

 

[mike]

Joe Bramblett, KD5NRH wrote:

"Michael A. Covington" <look@ai.uga.edu.for.address> wrote in
news:414a2466$1@mustang.speedfactory.net:


Assuming it's a CRT, indeed, it could be the video signal levels.
Look for a switch that selects the signal level.


Any idea where this would be on a Gateway EV910?


It could also be a problem with the high voltage circuit.


Anything in particular to check?


As a quick fix, IF YOU KNOW HOW TO WORK WITH HIGH VOLTAGE CIRCUITS,
there is generally an internal brightness setting.


Are you referring to the screen bias, or is there something else I should
be looking at?

The monitor was a freebie, but it's bigger than my current crop, so I'd
like to get it working. From what the previous owner said, it had to be at
100% brightness to look right when he got it, and it kept going downhill
over the course of about a year. Adjusting the bias got it readable, but
it's still noticeably dark.

I'm used to dealing with HV circuits in older TVs, but they didn't tend to
pack things in so tightly, so it was easy to trace out a circuit to find
the problem.

I had two ev700s with the same problem. Ev700s were made by different
vendors and most didn't have a screen adjustment on the flyback.
It's rumored that you can change a resistor on the board, but I never
found a schematic.
mike
--
Return address is VALID.
500MHz Tek DSOscilloscope TDS540 $2200
Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121
Bunch of stuff For Sale and Wanted at the link below.
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[LASERandDVDfan]

long story short, i have a ps2 and the lil grabber thingi that comes
up and spins the cd(know what i mean) spins,

The spindle motor.

but it won't come up to
the cd. i've opened it up, and it spins, and it does what it's suppose
to, except the spinner doesn't elevate to get the cd

Retime the drawer mecha.

There is a white slider with the same color peg that rides on a rail underneath
the drawer on the furthest right side corner of the console.

Make sure that the white peg is in the track underneath the drawer.

Reassemble and test. - Reinhart

 

[NSM]

"shs_bulldog" <shs_bulldog@hotmail.com> wrote in message
news:de8f1c9f.0410301837.3567c8a3@posting.google.com...
| Howdy folks,
| My name is Dustin and I found this group via Google. Today I found
| a TV on the side of the road, which is broken and I would like to
| repair. It's a nice TV, 27" six years old. The problem is that when
| you turn the TV on, the picture is very dark.
.....
| So what do you think, is this something someone could learn to fix?
| Thanks for time and advise.

Most public libraries have books on TV repair. Or
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2497604614

N

 

[Yukio]

Not Quite the same Problem, but related.

Most motor homes use a 12 Volt Inverter powered Flourescent Light .These
inverters operate in the 15 Khz range ! (More efficient then 60 cycle)
I was surprised to find out my Infra Red Remote Controller was not working
properly (ya , I put in new batteries and tried it close up) but it would
not operate at any distance.

To make a long story short, I had to shield the IR sensor in my satelite
dish receiver, from the Flourescent Room light Fixture.

Under normal conditions flourescent Lighting is driven by 60 cycle power,
and I am reasonably sure that the sensor circuits ar well filtered to block
this 60/120 cycle light interference. (Hi-Pass filter circuit)

In the case of 12 Volt lighting, these tubes are driven by a ~15 Khz
inverter and will appear as a 15/30 Khz modulated light ( modulation
invisible to the Human eye). .

This modulated signal even though in the visible light range, will leak
through the IR sensor and block the detector from responding to the ~15/30
Khz IR signal from the Remote Controller. Reducing the strenght of the
interfereing
room light by placing a magazine on top of the satelite receiver and shading
the detector , eliminated the problem..

BTW I like the LCD TV idea, I suspect your TV is a Trinitron, eg SONY . I
recall a rumour 20 or 30 years back that it produced a strong signal around
100/200 Khz, , the switching frequency for the trinitron screen. this would
explain the 10~200 pips per line you see in the interference.

I also like the DVD idea , should not be bothered by Trinitron .

All of their Remote Controls will still be bothered by 12 Volt Flourescent
lamps however !

Yukio YANO

"sandy" <paleonutsandy@yahoo.com> wrote in message
news:6d99d0e0.0410271340.3dac2bac@posting.google.com...

We've got a problem with our VCR that is about to drive us nutty! Our
motorhome has a TV/VCR compartment forward over the driver/passenger
seats. Cabinet is metal and you can see a jumble of TV cables and
other wires that appear to go to exterior lights. The TV, Amplified
antenna & VCR wires are all connect3d to a little black box
(Magnadyne); Power is from an inverter which we installed.

The TV works fine but the VCR has really annoying interference in the
way of wide rolling lines (composed of colored dots or thingies that
look like a line up of golf tees). When you take the VCR out of the
cabinet, it works fine. We've tried exchanging the VCR for another
and it still gets interferrence. We've tried expensive shielded
cables and it didn't help at all. We'd really, REALLY appreciate any
suggestions as to what the problem is and how we can fix it. We've
been pretending to fix it for over a week now and my husband is about
to drill holes in the dash and install the VCR there (and have cables
dangling from the dash to the overhead). Can you help!!!!!!!!!!?

Thanks!

Sandy

 

[mike]

Norm Dresner wrote:

"mike" <spamme0@juno.com> wrote in message news:417D71B6.7030009@juno.com...

Norm Dresner wrote:

Just to be clear, I recommended you use the lm317 to power the new 741.
The sine distortion is gonna be critically dependent on the stability
of this reference voltage. I never used a 317 anywhere I cared about
voltage stability and have no direct experience. May be just fine.
Also, if you use it to replace the supply, you also need to worry about
voltage differential when you short the 20V supply. Don't remember what
the max differential for a lm317 might be.

While you're at it, put some resistance in
pin 3 of U410 so C406 won't blast the input on power down.

mike


My point in checking for oscillations was that sometimes an oscillating

Op

Amp can give some very strange readings on a simply DMM.

Norm



Aha! I understand -- use the IC regulator to drop the voltage to the Op Amp
to a level where I could use a commercial grade safely. Good point.
Regarding max voltage inputs, I think I can safely use an LM7824 to drop
whatever the input is down to 24 volts to drive a jellybean 741 and I've got
one or two in some drawer somewhere around here.

Here's your quandry. You need high enough volts to supply 20V + 1 diode
drop + 2 resistor drops + the headroom the 741 needs to supply that
current. 24V might not be enough??? I haven't looked up the specs on a
741 in 25 years.
I always designed to a minimum trough voltage of 22V. It may be higher
depending on the max load on C400. You should measure the trough voltage
at maximum output and low line. That'll give you how much headroom you
have for the preregulator. It's probably gonna be a negative number.
That's why you'll have to decide how low you can let the line go and how
fine you can cut the 741 headroom.

As for C406, my circuit diagram shows a diode CR410 whose anode is connected
to the + side of the capacitor and the cathode to the V+ input to the Op Amp
to keep its input voltage no more than a diode drop above the supply
voltage. I couldn't find the diode on the circuit board anywhere or in the
parts location diagram but it's clearly on the schematic. If I can't find
it, I'll put a 1N4148 in as a "jumper"

The diode is not on my early schematic. The FG501 was one of the first
TM500 units designed. Over time the more glaring design mistakes got fixed.

Thanks
Norm

--
Return address is VALID.
500MHz Tek DSOscilloscope TDS540
Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121
Bunch of stuff For Sale and Wanted at the link below.
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[NSM]

"DavidPI73" <davidpi73@aol.com> wrote in message
news:20041031010837.27979.00003601@mb-m02.aol.com...
| I have a device that uses 6 AA Batteries at one time. One of the dual coil
| battery contacts is missing. Does anyone know where I can get a
replacement?
| I've tried Radio Shack and a hardware store and they didn't have one.
Thank
| you.

If it's a spring, try a hardware store. Many have assortments.

N

 

[Ol' Duffer]

In article <20041031010837.27979.00003601@mb-m02.aol.com>, davidpi73
@aol.com says...

I have a device that uses 6 AA Batteries at one time. One of the dual coil
battery contacts is missing. Does anyone know where I can get a replacement?
I've tried Radio Shack and a hardware store and they didn't have one. Thank
you.

I'm trying to figure out why it would be dual-coil.
Are the batteries in parallel? You might be able
to adapt the springs from an inexpensive battery
holder from Keystone or someone similar. Hardware
store stuff is not likely to be nickel plated, and
won't perform or last very well. If you are handy,
you can wind your own from music wire and plate it
with one of the hobbyist electroplate kits.

 

[John Del]

Subject: TV Repair, Can I do this?
From: shs_bulldog@hotmail.com (shs_bulldog)
Date: 10/30/04 9:37 PM Eastern Standard Time
Message-id:

1998 Zenith 27" Television, Model A25A02D
The audio is fine and the picture is crisp. However, the picture is
very dark, with too much red and green. The blue seems to be normal.

Stick a fork in it Dustin, it's done. Zenith TVs built from the early nineties
on have an almost comical failure rate of the picture tubes, your 25 inclulded.
You can raise the G2 control on the HV transformer to improve the brightness,
but the color will never balance.

There is also a posibility that one of the drive buffer transistors is bad,
giving you bad color as well, but they usually fail because the CRT is arcing
internally.

John

 

[Fred McKenzie]

<< I have a device that uses 6 AA Batteries at one time. One of the dual coil
battery contacts is missing. >>

David-

I've had similar problems. In one case there were ten cells in the pack.
After patching-up the old holder for several years, I finally replaced it with
a NiCd battery pack that had the same ten cells welded together. It occupies
slightly less than the space of the original holder. (Purchased from
www.batteriesamerica.com.)

In the other case, an MFJ-249 had six cells in a long holder, with three sets
of two cells. There wasn't room for the welded battery pack, and I wanted to
use expendable cells anyway. I ended up with a four-pack and a two-pack from
Radio Shack. They were the enclosed type of packs, and I disassembled one to
make a direct serial connection instead of just externally splicing the wires.
(I used the connector from a dead 9 volt transistor battery to mate with the
MFJ's connector.)

73, Fred, K4DII

 

[john]

What !! Are they hard up for buisness ?

kip

 

[NSM]

"Sam Goldwasser" <sam@saul.cis.upenn.edu> wrote in message
news:6wbrejniv4.fsf@saul.cis.upenn.edu...

| Or, see the TV repair guide at the site below. There are some simple
| problems that may cause a TV to be very dark but it's possible the TV
| was just used 24/7 for those 6 years and it's picture tube is tired.

I have a TV I bought in '82 that has only needed a couple of tweaks over the
years to keep it going (it has one of those service switches which helps).
BTW, I used to find old computer monitors that were so dim they could barely
be read. I'd peel off the fabric glare protectors and wipe 1/4" of gunk off
the screen and they'd really stand out again!

N

 

[NSM]

"Leonard Caillouet" <no@no.com> wrote in message
newsH6hd.1067$ep3.915@lakeread02...

....
| > It isn't just heat that does the job. It's a combination of materials,
| > cleanliness, flux and heat. I've soldered everything from litz wire to
bus
| > bars and preparation is the key.
|
| You are very much correct except that it is heat that does the job. The
| cleaning is necesary for the heat to occur where you want it.

If that were true you could solder aluminum to aluminum - or bananas. I can
solder aluminum to aluminum with regular solder, but it isn't heat that does
the trick - it's oil.

N

 

[Mike Diack]

tomg@fullnet.com (Thomas P. Gootee) wrote in
news:11915d6.0410310849.7b1d1756@posting.google.com:

If anybody has any old Western Electric Nassau solder laying around, I
would like to buy some.

It keeps coming up on fleabay at looney prices.
M

 

[NSM]

"Mike Diack" <moby@kcbbs.gen.middleearth> wrote in message
news:Xns95944D8A966C4mobykcbbsgennz@203.96.92.12...
| tomg@fullnet.com (Thomas P. Gootee) wrote in
| news:11915d6.0410310849.7b1d1756@posting.google.com:
|
| > If anybody has any old Western Electric Nassau solder laying around, I
| > would like to buy some.
|
| It keeps coming up on fleabay at looney prices.

Why?

N

 

[Franc Zabkar]

On Fri, 29 Oct 2004 13:49:25 -0400, "Team Goon"
<teamgoon@ilovespam.comcast.net> put finger to keyboard and composed:

Top posting is the deault.

Care to explain?


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[Franc Zabkar]

On 31 Oct 2004 06:08:37 GMT, davidpi73@aol.com (DavidPI73) put finger
to keyboard and composed:

I have a device that uses 6 AA Batteries at one time. One of the dual coil
battery contacts is missing. Does anyone know where I can get a replacement?

I don't like your chances. After many such problems, I've resorted to
salvaging the battery contacts from everything I discard. I can't
understand why these things aren't stocked as spare parts. :-(


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[Luddite]

Mike Diack <moby@kcbbs.gen.middleearth> wrote:

tomg@fullnet.com (Thomas P. Gootee) wrote in
news:11915d6.0410310849.7b1d1756@posting.google.com:

If anybody has any old Western Electric Nassau solder laying around, I
would like to buy some.

It keeps coming up on fleabay at looney prices.

search for -nassau "pedigreed" solder- and have a look,40 year old
45/55 solder on a rusty spool with two bids.