Toshiba TV29C90 problem; Image fades to black...

[Daniel Laframboise]

Hi Loren,

I just ran downstair and looked on the inside of the pannels and I
can't find any diagrams.

Thanks anyway,

Dan.

Loren Coe <loren@netnews.attbi.com> wrote in message news:<vU86b.272151$cF.85210@rwcrnsc53>...

In article <b29accb3.0309030653.7ce39e65@posting.google.com>, Daniel Laframboise wrote:
Good day.

We have an old BEST Ferrups FC15KVA UPS and it doesn't work.

I would like to know where I could get a service manual for that unit.

I know it's not recommended to play around in those units, but our
company has an electrical department with qualified electrician and
even an electrical P.Eng.

So, on that side, I think we're pretty well covered.
Thanks, > > Dan.

there s/b a diagram on the inside of a panel. most elec.
techs s/b able to diagnose w/o the manual unless it is
an exotic type w/pcb's. --Loren

 

[Ken_B]

Hi...

Yes, the color problem happened rather suddenly. One day it was OK, the next
day a program I taped had the color problem when played back. The color was
OK when I played it on a different machine. I've done a couple of head
cleanings to no avail.

Thanks.

Ken

"Ivanhoismine" <ivanagen@aol.commensense> wrote in message
news:20030910094516.22044.00000720@mb-m04.aol.com...

I've seen this problem resolved with a good head cleaning but if that
doesn't
work, you may need a new amplifier chip. Did the color anomalies develop
suddenly or over time? If the former is the case, you're probably in for
an
expensive/time consuming repair

 

[Asimov]

"Jason D." bravely wrote to "All" (10 Sep 03 03:48:33)
--- on the heady topic of "Big battle with WEIRD vertical deflection problem in PTK195 chassis."

If there are spikes in the output ramp then it would seem like a supply
filter electro problem to me. Have you checked what the supply noise
looks like on the scope? If not then the pump up might be off value.


JD> From: jpero@sympatico.ca (Jason D.)

JD> Quickie on the type of vertical circuit:
JD> For others who isn't famillar with this PTK195 as well as CTC197
JD> chassis, this vertical circuit is virtually same in CTC17x, 18x, 203
JD> and up using TDA8172 vertical IC.

JD> This set came in with blown vertical IC and a very crispy 1 ohm 2W
JD> resistor (snapped in two when I took it out) for 26V supply to the
JD> vertical only. Fixed that up. Gee that's a FIRST for me to actually
JD> have to replace that in RCA in my 1 and half years for a shop.

JD> Well! This one really got me stumped, top most is bowed in,
JD> non-linear lines and all shaking like mad while most of pix is
JD> perfect. Got all my tools on that (scope, dmm and ESR meter) All the
JD> 26V and 13V supplies are quiet and smooth, caps checks good EXCEPT: on
JD> scope on output of vertical IC I see this like this:

JD> Retrace pulse as it should be, then a normal clean ramp down to appox
JD> mid way then I see high frequency noise centered around that ramp down
JD> to the bottom just before the retrace pulse I see few sharp tall thin
JD> spikes. Reminds me like this imagine chroma waveform without steps
JD> with half top the pix b/w and half bottom in color.

JD> Even I subbed a good yoke on each of R, G, G yoke connectors in turn
JD> with no luck hoping to catch a bad yoke.

JD> When this that JURG6006's came up with this vertical IC problem on
JD> "Subject: Mit. VS5010 intermittent shutdown" my attention snapped up
JD> and had to post mine too.

JD> That vertical noise is confusing the top convergence area so bad that
JD> top part is jumping around: straight and bowed irratically.

JD> BTW: I tried another RN14501 with no luck, the sawtooth input is
JD> clean at that RN14501.

JD> Cheers,

JD> Wizard

.... Resistance Is Futile! (If < 1 ohm)

 

[Leonard G. Caillouet]

Denon, Tritronics, several other distributors, if it is still available.
That unit is about 25 years old isn't it?

Leonard Caillouet

"Klaus" <birkla2000@yahoo.dk> wrote in message
news:b960c622.0309100350.78e4e9d7@posting.google.com...

Hi.
I looking for schematics/diagrams for the Denon PMA-520 amplifier,
where kan i get it?

Thanks

 

[playoff]

Hi again,
which article i should refer to regarding my problem?

http://www.repairfaq.org/REPAIR/F_monfaq.html

Thanks all!


"Jerry G." <jerryg@total.net> wrote in message news:<bja116$jq5$1@news.eusc.inter.net>...

This looks like the blue gun in the CRT may be shorted, or some
components failed in the video drive circuits to the CRT causing it to
be biased incorrectly. The CRT being shorted is the most common cause
of this.

The drives to the CRT are verified by measuring the DC biases to the CRT
guns on its various elements, and then checking the video signal drive
to the grids and or cathodes.

As for using parts from an older TV, if it is not the exact same model,
chances are the part types are not compatible, except for some of the
generic parts. .

--

Greetings,

Jerry Greenberg GLG Technologies GLG
==============================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
Instruments http://www.zoom-one.com/glgtech.htm
==============================================
"playoff" <playoff@hotmail.com> wrote in message
news:96993112.0309050320.1796a5e9@posting.google.com...
Dear Sir,

I would like to know what happened to my tv.
Everytime I switch on, the screen color will become darker and there
are a lots of lines appear. I have took photos using my digital
camera. Please have a look. I am wondering can I fix it myself or any
economy method to fix the problem.
I have another old tv which hopefully I can get some parts from there.
Thank you very much.
Your time is appreciate.

Here are the photos
http://www.143.cn/tv1.jpg
http://www.143.cn/tv2.jpg

 

[john]

Did you hook it up to Cable ???

kpi

--
"Watch the return E-Mail addy its false"
"Chook" <collectorz2002@yahoo.com> wrote in message
news:e1a6a20.0309100930.4cba0cab@posting.google.com...

Mother gave me this tv without a remote. When turned on it's stuck on
the video (blue) screen and I can't get it off. Anyone know what I can
do to fix it? Do I need the remote? If I have to get it repaired
anyone have an idea how much it will cost? Any help will be very much
appreciate. Thanks.

 

[Eric]

who made it? what does it do?
"max" <maxg70@cwnet.com> wrote in message
news:vltr8mlun9ei6d@corp.supernews.com...
: Hi
: I'm looking for datasheet for TDA4486
: Thank you
:
:

 

[rstlne]

"Ricardo Matos Abreu" <no_spam_please_ricardo@avoiding_spam_av.it.pt> wrote
in message news:1063215841.131520@proxy1.ua.pt...

"rstlne" <who@who.com> wrote in message
news:UPC7b.849$3z4.7688@newsfep4-glfd.server.ntli.net...
..
Hi I am new to this group and new to electronics kinda.. I am a
industrial
instrument technician by trade and I have done some repair on board
level
but most of it was down to me having test sheets and knowing voltages on
points and using that info to really limit the fault down. But now I
have
2
SwitchMode power supplys and I would like to try and fix them, I have
check'd all of the resistors on the board and none of them are shorted
(not
sure about open as I could bee seeing the circut resistance).. I check'd
the
transistors (resistance from emitter to collector and vice versa).. I
also
check'd the caps and they all seem fine (not to mention they are all
clean
and non buldged)..

both supplys give the +5v VSB but when I turn them on (active low on the
line) then none of the outputs seem do do anything.. My guess is that
the
regulator chip is damaged (oscillator or comparitor specifically).. all
I
have is a basic multimeter so checking things like the wave output from
the
chips or even the driven output from the amps is something that I cant
do
I
dont think.

Now that I am through that explanation I will jump to the point where I
want
advice. Where can I find circut diagrams for common pcb's (web page) (I
know this same board is used for more than one PSU supplier) and is
there
a
web page that would also give me the resource links to ic's made by
different mfgrs..

Regards
rstlne



You may find a tuturial about switchmode power supplies (SMPS) at
www.repairfaq.org

The first thing that crossed my mind was the supply loading. As you may
know, a SMPS needs a minimum load at the output(s) in order to regulate
properly. This minimum load, of course, is different from design to
design.
Some SMPS shut off when they have no load connected. This may be your
case.

Ricardo

Okay, thanks i'll throw a old drive onto the output tonight to load it down,
I kinda made the assumption that the tank/whatever circut on the output of
the transformer & my dvm would give it enough load ot regulate. This could
well be why I am seeing no results, I know that computer switch mode supplys
are supposed to operate (not burn up) with no load, according to the intel
specifications for atx supplys.. hopefully this is the fault and i'll find
the problem..
Thanks for the link

Jon

 

[Tom MacIntyre]

On Mon, 8 Sep 2003 19:05:06 -0400, "john"
<va3mmTAKEOUTTHIS@niagara.com> wrote:

We need Model Number and Chassis number
as RCA has made hundreds of different Models.


kip

If the warranty just ended it makes it easier...what are they into
now, PTK 2??.

Tom

 

[Impmon]

On 10 Sep 2003 19:22:59 GMT, decij@aol.com (Decij) typed:

This has been a good camcorder, and I don't want to have to buy a
new one if I can avoid it.

Have you tried www.ebay.com ? Sometimes there's a non working camera
there that goes cheaply. You could buy one for spare parts including
replacement view finder.
--
All viruses and spams are automatically removed by my ISP before
reaching my inbox.

 

[Steve Reinis]

It should have all needed keys on the front panel.

Hit MENU and you will see two options. "+" for Features and "-" for Video
Adjust.
Hit the Volume Up key, which is "+" to select the features menu.
Use the Channel Up key to scroll through until you see the INPUT option.
Hit the Volume Up "+" key to swap between the tuner and the video inputs.

MENU will get you out.

-Steve

Chook <collectorz2002@yahoo.com> wrote in message
news:e1a6a20.0309100930.4cba0cab@posting.google.com...

Mother gave me this tv without a remote. When turned on it's stuck on
the video (blue) screen and I can't get it off. Anyone know what I can
do to fix it? Do I need the remote? If I have to get it repaired
anyone have an idea how much it will cost? Any help will be very much
appreciate. Thanks.

 

[eddumokweer]

Hi,

Also I think the repairman will go for a 100% job, and don't like repeating
repairs.
With water you can be lucky or you have a problem as repairman, just like
gambling.

Greetings Peter

"Ian Stirling" <root@mauve.demon.co.uk> schreef in bericht
news:bjotip$g51$3$8302bc10@news.demon.co.uk...

Jeff <freelait2000@yahoo.com> wrote:
Hi,
My Sony mini-DV accidently dropped into water at the weekend. The
camcorder was in bags for 5 minutes in the lake. Monday, I asked the
snip
any comments are appreciated.

Was the battery in it at this time?
If so, especially if you diddn't take the battery out immediately,
you've almost certainly got corrosion in the power supply circuitry.
Add to this that it's been wet for a couple of days, and the LCD has
conductive traces made of nanometer thick conductors, and it's probably
toast.

Washing in alcohol may have removed all of the water, though there may
be some remaining under SMD chips.
To ensure that this isn't the case, putting all the boards in an oven
at 110C for a couple of hours works. (don't do this with the LCD)

If you think it's completely dry, you might try powering it on.
But there may well be damage to the power supply, in which case this
may cause further damage.

The lens assembly probably needs dissasembled, cleaned and relubricated,
if it's not to suffer in the future, which is another big job involving
a mass of tiny parts and generally lots of small springs.


--
http://inquisitor.i.am/ | mailto:inquisitor@i.am | Ian
Stirling.
---------------------------+-------------------------+--------------------
------
"The device every conquerer, yes, every altruistic liberator should be
required
to wear on his shield... is a little girl and her kitten, at ground zero"
- Sir Dominic Flandry in Poul Andersons 'A Knight of Ghosts and
Shadows'

---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.515 / Virus Database: 313 - Release Date: 1-9-2003

 

[Isaac Wingfield]

In article <o%s7b.7486$Ej.1143603@ursa-nb00s0.nbnet.nb.ca>,
"Chris F." <zappyman@nospam.com> wrote:

Got this old ELAC 3400T receiver, made in Germany in the early 70's. I'm
told there's a good market on Ebay for European high-end audio products, so
I'm hoping to fix it up for sale. So far the repair hasn't been too tough,
but there's just one detail remaining. A diode on the right-channel audio
preamp board is shorted - a result of a solder splash I made while replacing
some caps. The only markings are three color bands, from anode side: red,
brown, blue. I compared it with an identical part in the left channel, all I
can determine is that it's not a zener diode (no measurable voltage across
it). I do know it's a diode, by the schematic symbol on the board. At this
point I can only take a guess, but what would be a prudent guess to take? A
low-voltage, high-speed switching diode is the only thing I can think of.
Obviously, I don't want to do any further damage and I want the unit to work
reliably for it's next owner.
Thanks for any advice.

In an audio unit, I'd suspect that the forward voltage drop would be the
most important parameter, not switching speed.Possibly the diode is
being used as a bias element -- perhaps to provide some temperature
compensation. In a design from the early '70's, it might be a germanium
device with a 300 mV drop vs. ~600 mV for silicon. Measure the good one
while it's operating tofind out which.

If you need a replacement for a germanium diode, BE CAREFUL. Most
"equivalent" devices you find these days are really silicon, NO MATTER
what their type number is - I've seen silicon devices marked "1N34" for
example. You may have to find some old surplus gear to get a *real*
germanium diode.

Isaac

 

[JW]

On Wed, 10 Sep 2003 11:16:20 +0100 "rstlne" <who@who.com> wrote in Message
id: <UPC7b.849$3z4.7688@newsfep4-glfd.server.ntli.net>:

Where can I find circut diagrams for common pcb's

Look in alt.binaries.schematics.electronic

I posted a typical ATX power supply in .gif format for you, with the
subject "ATTN: "rstlne" Here is your request"

Good luck!

 

[rstlne]

"JW" <none@dev.nul> wrote in message
news:l1k0mv8n9j83r4bfkjnqdobb455sjhfc83@4ax.com...

On Wed, 10 Sep 2003 11:16:20 +0100 "rstlne" <who@who.com> wrote in Message
id: <UPC7b.849$3z4.7688@newsfep4-glfd.server.ntli.net>:

Where can I find circut diagrams for common pcb's

Look in alt.binaries.schematics.electronic

I posted a typical ATX power supply in .gif format for you, with the
subject "ATTN: "rstlne" Here is your request"

Good luck!

Thanks for that, I did find the french version when I started searching a
while back, Using that I was able to take my "general" idea of how a switch
mode works and apply it to how a pc supply will (or roughly will) work.
both of my supply's are slightly different from this. the main difference
being the optocoupler that goes back to the primary. The other big problem
is that the same "design" chip doesnt seem to be used for all 3 supplys (one
in photo) and 2 I have. I was able to dig up the data sheets on one but not
the other (drc183).. I did find a diagram here (yay)
http://www.webx.dk/oz2cpu/radios/psu-pc400.htm and the pcb is the same make
as mine (but the unit is not the same mfgr and most of the componets are
also different)

Regards
rstlne

 

[john]

Try MCM they are on line.

kip

--
"Watch the return E-Mail addy its false"
"Riyad" <mine_only_mine2222@yahoo.com> wrote in message
news:cdf4bdad.0309102119.13ba1b3d@posting.google.com...

In a GE television model no. 25GT270 I accidenly blew out an IC with
the following numbers on it:

15490-470
TCE 1999*JCP
M22150110Y
[ST] MATLA

I am more of an electronic hobbyist than a repair man. I am used to
buying my parts in an electronic store. This part appears to be one
customized to this television and will not be available in stores. So
where to I get this part for the GE televsion? Is there a GE parts
location that supplies this?

This is very important because I turned my friend's television from
one that was mostly working to a something dead that won't even power
on.

 

[Mark D. Zacharias]

Sounds like a motor is shorted. Sony's replace the entire pickup ass'y
complete with motors. A bit pricey, but it should fix your problem.

Mark Z.


"Koji San" <apple26pie@yahoo.com> wrote in message
news:fa1ef2c1.0309110412.1ee28e1c@posting.google.com...

My DVD does not power up when pressing power button. A tiny standby
light can be seen. But after opening up the unit, I’ve located
an orange blown fuse similar to a resistor on the power supply board.
It’s labeled P115. This fuse is stamped with “750”
on it. I’m not sure what 750 stand for but after replacing this
with an identical replacement (750) it works fine but blows after
pressing ‘disk skip’ button. Soon I got an idea and
replace it with a 43-Ohm resistor and the unit powers up and works
till today.

But here’s the catch. The 43-Ohm resistor heats up too hot to
the touch when the CD tray is opening or closing. The display will
dim when pressing disk skip far to many times. To reset the dimming
light I have to unplug it from the wall. I fear it may burn the chip
that controls the motor one-day. What is the best approach to solve
this problem?
Koiji

 

[Sam Goldwasser]

"Mark D. Zacharias" <mzacharias@nospam.earthlink.net> writes:

Sounds like a motor is shorted. Sony's replace the entire pickup ass'y
complete with motors. A bit pricey, but it should fix your problem.

If it's a simple permanent magnet motor, the short may be due to
a buildup of contamination on the commutator. This can sometimes
be easily removed. Just putting a Band-Aid on the problem by increasing
drive means it will come back, probably quite quickly. Additional damage
may be the result if the driver can't handle it.

See the CD repair guide for info on motors.
http://www.repairfaq.org/sam/cdfaq.htm#cdmot

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: The email address in this message header may no longer work. To
contact me, please use the Feedback Form at repairfaq.org. Thanks.

Mark Z.


"Koji San" <apple26pie@yahoo.com> wrote in message
news:fa1ef2c1.0309110412.1ee28e1c@posting.google.com...
My DVD does not power up when pressing power button. A tiny standby
light can be seen. But after opening up the unit, I’ve located
an orange blown fuse similar to a resistor on the power supply board.
It’s labeled P115. This fuse is stamped with “750”
on it. I’m not sure what 750 stand for but after replacing this
with an identical replacement (750) it works fine but blows after
pressing ‘disk skip’ button. Soon I got an idea and
replace it with a 43-Ohm resistor and the unit powers up and works
till today.

But here’s the catch. The 43-Ohm resistor heats up too hot to
the touch when the CD tray is opening or closing. The display will
dim when pressing disk skip far to many times. To reset the dimming
light I have to unplug it from the wall. I fear it may burn the chip
that controls the motor one-day. What is the best approach to solve
this problem?
Koiji

 

[Chook]

"Steve Reinis" <noemail@all.com> wrote in message
Menu options will not allow me to change off video. The selection to
change it are red and it skips them. There has to be some sort of
memmory problem that will not reboot ro reset by unplugging. I'm going
to buy a controller but I don't think it will fix it. I hook up
video/audio cables from my VCR to the TV Input and the picture came on
for exactly a second and then went back to the blue video screen
however I was still getting audio. Anybody know anything about this
problem? It's almost like a memory chip or something is bad which
causes it to stay on the video screen. Everything is hooked up
properly just stuck on video. Please help if you know something about
this. thanks.


news:<bjovhk0236u@enews4.newsguy.com>...

It should have all needed keys on the front panel.

Hit MENU and you will see two options. "+" for Features and "-" for Video
Adjust.
Hit the Volume Up key, which is "+" to select the features menu.
Use the Channel Up key to scroll through until you see the INPUT option.
Hit the Volume Up "+" key to swap between the tuner and the video inputs.

MENU will get you out.

-Steve

Chook <collectorz2002@yahoo.com> wrote in message
news:e1a6a20.0309100930.4cba0cab@posting.google.com...
Mother gave me this tv without a remote. When turned on it's stuck on
the video (blue) screen and I can't get it off. Anyone know what I can
do to fix it? Do I need the remote? If I have to get it repaired
anyone have an idea how much it will cost? Any help will be very much
appreciate. Thanks.

 

[Jeff]

Several other questions:
1. I find the color of the dew sensor is dark. Then I used Q-tips to
clean it with alcohol. The golden color of the metal line appears,
some of the black color between the metal lines was removed. Now, I
wounder the black color was caused oxidation, or not. I don't want to
damage the dew sensor.
2. How many motors totally are there in the cassette deck? I just see
the loading motor.
3. To reassemble all the PCB altogether is a big job. And there are
the oppertunities some damages are in some board. What is the minimum
number PCB to connect to work? For example, as one of you said, LCD is
dead. Can I connect the two back-to-back main board, CCD board, power
switch and battery (plus view finder module or AV output jack) to test
the board?
4. I have not applied voltage to the loading motor. Is the polarity of
the voltage important or not? How to identify the right polarity?

Ian Stirling <root@mauve.demon.co.uk> wrote in message news:<bjotip$g51$3$8302bc10@news.demon.co.uk>...

If you think it's completely dry, you might try powering it on.
But there may well be damage to the power supply, in which case this
may cause further damage.

When the camcorder dropped into water, the battery was in without the
power switch turned on. This will also damage the pwr cirtuit. How
severe is it?

The lens assembly probably needs dissasembled, cleaned and relubricated,
if it's not to suffer in the future, which is another big job involving
a mass of tiny parts and generally lots of small springs.

I would like to know more the procedure about the lens assembly
cleaning. Could you point me in that direction?


Thanks a lot.