Toshiba TV29C90 problem; Image fades to black...

"Rheilly Phoull" <Rheilly@bigpong.com> wrote in message
news:43f45521$0$22049$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
"fixpc" <fixpc@withoutemail.com> wrote in message
news:43f44f26$1@127.0.0.1...
I have deviced method to desolder a capacitor from motherboard much
easily and without burning a single finger by using single hand ( 5
fingers) in about 10-20 seconds.


Well ya gonna tell us genius ?? Or are we supposed to plead for this
breakthrough in an elementary task?

--
Regards ......... Rheilly Phoull
I guess if ya have fewer than 5 fingers per hand yer SOL! <snicker>
 
Ray L. Volts wrote:
"Rheilly Phoull" <Rheilly@bigpong.com> wrote in message
news:43f45521$0$22049$5a62ac22@per-qv1-newsreader-01.iinet.net.au...

"fixpc" <fixpc@withoutemail.com> wrote in message
news:43f44f26$1@127.0.0.1...
I have deviced method to desolder a capacitor from motherboard much
easily and without burning a single finger by using single hand ( 5
fingers) in about 10-20 seconds.


Well ya gonna tell us genius ?? Or are we supposed to plead for this
breakthrough in an elementary task?

--
Regards ......... Rheilly Phoull


I guess if ya have fewer than 5 fingers per hand yer SOL! <snicker
Hmmm, I've only got 4!!
 
On Thu, 16 Feb 2006 10:34:16 -0000, "carl0s"
<carl@noitsnotcss-networks.commy.invalid> wrote:

I am experimenting repairing a dead thinkpad x20. The machines power light
flicks momentarily when the dc jack is inserted or removed.
I accidentally shorted a couple of pins on this IC, and now the behaviour is
much different, with lights doing funny things.

Anyhoo, the machine was dead to begin with..

I wonder if somebody could please tell me what this IC does, and how I might
find a replacement to try out?

Here's a picture:
http://www.uk2sucks.net/ic.JPG

thanks,
Carl

It's a mosfet switcher that provides 5 volts for the usb port.
Digikey in the United States sells these. Chuck
 
What if I'm all thumbs? Does that make it easier or harder?

Rheilly Phoull wrote:
Ray L. Volts wrote:

I guess if ya have fewer than 5 fingers per hand yer SOL! <snicker

Hmmm, I've only got 4!!
 
Thanks, that works.
What about that Zener on the output of the vertical IC?
15V? 18V?

In article <7hsGf.8308$bW6.7325@bignews7.bellsouth.net>,
nospam@noway.com says...
> 6.8 ohm
 
On Thu, 16 Feb 2006 10:34:16 -0000, "carl0s"
<carl@noitsnotcss-networks.commy.invalid> wrote:

I am experimenting repairing a dead thinkpad x20. The machines power light
flicks momentarily when the dc jack is inserted or removed.
I accidentally shorted a couple of pins on this IC, and now the behaviour is
much different, with lights doing funny things.

Anyhoo, the machine was dead to begin with..

I wonder if somebody could please tell me what this IC does, and how I might
find a replacement to try out?

Here's a picture:
http://www.uk2sucks.net/ic.JPG

thanks,
Carl
There are several X20 motherboards on ebay right now. One is bad, but
might be used as a parts source. If it was my laptop, I'd just buy a
working one from ebay. The chances of repairing a laptop motherboard
are slim to none unless you know exactly what's wrong with it.
Andy Cuffe

acuffe@gmail.com
 
On Thu, 16 Feb 2006 10:34:16 -0000, "carl0s"
<carl@noitsnotcss-networks.commy.invalid> put finger to keyboard and
composed:

I wonder if somebody could please tell me what this IC does, ...

Here's a picture:
http://www.uk2sucks.net/ic.JPG

Siliconix Si4435 P-Channel 30-V (D-S) MOSFET:
http://www.vishay.com/docs/70149/70149.pdf
http://www.vishay.com/doc?72123

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
 
"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message
news:deo9v1tj6u8jcjr04o6mtvkkjo27dk26g9@4ax.com...
On Thu, 16 Feb 2006 10:34:16 -0000, "carl0s"
carl@noitsnotcss-networks.commy.invalid> put finger to keyboard and
composed:

I wonder if somebody could please tell me what this IC does, ...

Here's a picture:
http://www.uk2sucks.net/ic.JPG


Siliconix Si4435 P-Channel 30-V (D-S) MOSFET:
http://www.vishay.com/docs/70149/70149.pdf
http://www.vishay.com/doc?72123
Thanks everybody, your help is very much appreciated. Thanks for the eBay
pointer. I have just purchased a replacement board for Ł43 including
delivery. Out of interest, is this MOSFET for the USB port then or something
else?
 
I usually use Chipquik for the stubborn ones. Slowly lifting one lead
(use a temp controlled iron though) then the other alternately seems to
work as well.

-A
 
On Sat, 18 Feb 2006 11:25:08 -0000, "carl0s"
<carl@noitsnotcss-networks.commy.invalid> put finger to keyboard and
composed:

"Franc Zabkar" <fzabkar@iinternode.on.net> wrote in message
news:deo9v1tj6u8jcjr04o6mtvkkjo27dk26g9@4ax.com...
On Thu, 16 Feb 2006 10:34:16 -0000, "carl0s"
carl@noitsnotcss-networks.commy.invalid> put finger to keyboard and
composed:

I wonder if somebody could please tell me what this IC does, ...

Here's a picture:
http://www.uk2sucks.net/ic.JPG


Siliconix Si4435 P-Channel 30-V (D-S) MOSFET:
http://www.vishay.com/docs/70149/70149.pdf
http://www.vishay.com/doc?72123


Thanks everybody, your help is very much appreciated. Thanks for the eBay
pointer. I have just purchased a replacement board for Ł43 including
delivery. Out of interest, is this MOSFET for the USB port then or something
else?
AFAICT, you have two SMPS circuits in the photo. One uses a low power
MOSFET (Si4435), the other uses a higher power MOSFET (SUD50N03-10).
If I'm right, then there should be two PWM controller ICs nearby. You
can determine the output voltage of each circuit by inspecting the
values of the resistors around the PWM controller IC's error amp pins.
A USB port requires +5V, while the mainboard may run on 3.3V. If you
need more assistance in this area, then a larger photo might help.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
 
Lockergnome1 Wrote:
...I found 2 large resistors, constructed of some material
printed in a spiral around a ceramic cylinder. Both were cracked at
one end (where they were screwed to the pobe tip and the rest of the
meter...possibly someone screwed the unit together with too much
force.) One was labelled as 800 megaohm (!!!) made by Beman Mfg. Inc,
Component Division. ...
Those cylinders btw are the little electrostatic generators that are
inside of electrostatic paint guns (for one thing). The one I have is
in a Graco AS 4000 and is labelled 500 megaohms. Since this is static
electricity the ohms ala voltage gets very high. Hope this helps. - J


--
jenjhall
 
I too have the same model television. It seems this is the most common
problem for these units. On mine however, you can hear the tv click
when you press the power button. I have removed the back and the fuse
is still good. In fact the red indicator light (on the circuit board
inside tv) comes on when you turn the tv on. Neither the outside
indicator light or the screen however come on. Its as if the tv is
turning partially on, but not all the way. Any advice would be helpful.
I just dont see the reason to take it to a repair shop. I'd rather see
if I can get it fixed myself. And if anyone has the service manual for
it... I would appreciate that too. Thanks

Matt Walker (oldskoolplaya806@hotmail.com),
Lubbock TX


Bob Shuman Wrote:
Angela,

I have the same model manufactured at approximately the same time
frame. We
have not experienced the problem you describe, but I did have the main
power
on/off relay go bad so it had to be replaced. I only mention this
since it
was a pretty easy fix and if you can't find any cold solder joints on
the
main
power board you may want to check the resistance of the relay contacts
themselves (mine would stick closed after the set was turned off, but
I
could
imagine that they could just as easily become resistive and have the
potential to
fail in the manner you describe as well).

After dismissing cold solder and checking the other components Leonard
cited, I'd look at the relay. Hope you can get this fixed. We still
love
our set. If you need a schematic, let me know as I think I have the
service
manual somewhere.

Bob

"Angela D'Andrea" adandrea@austin.rr.com wrote in message
news:73a7a341.0311160728.26a6f322@posting.google.com...-
We have a Hitachi Ultravision Model 50UX26B projection TV that was
made in July 1996. Lately it has been shutting itself off at random
times. Hitting the power button on the remote usually turns it back
on again (you actually need to hit the power button twice; the first
time you hear the TV click and the second time it comes on).

Thanks for you help.

Angela D'Andrea
Austin, Texas-

--
oldskoolplaya806
 
Thanks, but the cord is fine - it's mainly the wiring that goes between the
top and the bottom. Every time the lid is raised, that wire is flexed and
the insulation is deteriorating.

WT

"Bob AZ" <rwatson767@aol.com> wrote in message
news:1140582006.925155.262830@g47g2000cwa.googlegroups.com...
Go to an Ace Hardware or the like and buy a new cord. Already made up
and ready to wire in. The wire will be HPN.
Bob AZ

*** Free account sponsored by SecureIX.com ***
*** Encrypt your Internet usage with a free VPN account from http://www.SecureIX.com ***
 
"Bob AZ" <rwatson767@aol.com> writes:

Go to an Ace Hardware or the like and buy a new cord. Already made up
and ready to wire in. The wire will be HPN.
He may be talking about internal wiring. Go to an appliance repair shop and
buy a couple feet.

--- sam | Sci.Electronics.Repair FAQ: 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 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 Form in the FAQs.
 
In article <1140609700.574000.203690@o13g2000cwo.googlegroups.com>,
<chase_p_a@yahoo.co.uk> wrote:
I hoped that some cheap BD441/442 transistors might be sufficient for
me to find out if the rest of the circuit was OK. They are at least
rated for the voltage (73 volts rail-to-rail). But putting them, and
new 0.27R resistors, in the circuit and powering-up resulted in smoke.
I guess their characteristics (higher gain, lower current) are too
different, or there's something else wrong with the circuit. At least I
only blew up a few pence/cents worth of components.

Any suggestions about equivalent transistors at sensible price? Any
ideas how I can try things out while minimising the chance of more
fireworks?
The power amp appears to be direct coupled so I'd guess a few blown up
transistors back down the line too.

--
*Women who seek to be equal to men lack ambition.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
 
"Dave Plowman (News)" <dave@davenoise.co.uk> wrote in message
news:4dfd311c5bdave@davenoise.co.uk...
In article <1140609700.574000.203690@o13g2000cwo.googlegroups.com>,
chase_p_a@yahoo.co.uk> wrote:
I hoped that some cheap BD441/442 transistors might be sufficient for
me to find out if the rest of the circuit was OK. They are at least
rated for the voltage (73 volts rail-to-rail). But putting them, and
new 0.27R resistors, in the circuit and powering-up resulted in smoke.
I guess their characteristics (higher gain, lower current) are too
different, or there's something else wrong with the circuit. At least I
only blew up a few pence/cents worth of components.

Any suggestions about equivalent transistors at sensible price? Any
ideas how I can try things out while minimising the chance of more
fireworks?
use a variac (variable AC source) to slowly bring the voltage up. wire a
light bulb in series with it. (about 100W for this case i guess) if the lamp
starts to glow brightly when you bring up the voltage with no audio signal
then something is still wrong.



The power amp appears to be direct coupled so I'd guess a few blown up
transistors back down the line too.




--
*Women who seek to be equal to men lack ambition.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
 
The power amp appears to be direct coupled so I'd guess a few blown up
transistors back down the line too.
Some amplifiers of this vintage were DC couple all the way back to the
pre-amp'. The only sure way to repair them was to replace every
transistor
on board and very carefully check all resisistors and caps' before
firing up.

You may also find such devices as pots to balance the output
transistors
bias which if not properly set will again send out smoke signals.

The things really were a pain in the arse with some amps' blowing up
even
if the loudspeakers were left disconnected!
 
I tested several of the little transistors as best I could, with them
still on the board. However, perhaps I should have taken them off the
board (tedious) to be sure.
 
Thanks. The pre-amps are working OK.

Yes, there is a "DC Balance" preset and a "Bias" preset.

Oh, it all sounds too hard. Plan B beckons.
 

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