Toshiba TV29C90 problem; Image fades to black...

When the Unite is cold the overvoltage SCR will fire, replaced the SCR, you
can also blow freeze on the SCR and it will latch.

The over voltage circuity is on the other end of the board, and all voltages
are OK.

Could be that the DV/DT specs of the SCR are to low or the SCR specs change
when its cold, or the inverter is running to fast

Has a look at some specs and this is funny as this problem could only happen
when the SCR get hot..


This Scope is not mine and has been sent to Philips many times, but they gave
up on it in the end.


There are 4 Diodes been added around the SCR that are not shown on the
circuit, may be that was a Philips attempt to fix it.


SCR BT151 is a low gate sensitivity & DV/DT 200v/us

Also sold as a Fluke PM3055


Any one know of any mods for this, or the frequency of the PSU Inverter.


Thanks
 
Dave:
I would the small electrolytic capacitors that are part of the
driver circuit for these transistors. They are usually located
nect to the driver transformer. Use an ESR meter, or just replace
them if in doubt.
Many better monitors use an FET to regulate the supply voltage
going to the flyback and sweep transformer. Sometimes the FET
will short or the electrolytic capacitor will weaken causing the
FET to fail to regulate properly.
Of course, the flyback (LOP transformer) might be going bad,
which means it is time to look for another monitor.
Hope this helps...
John
 
Meirman:
You need the original "factory" remote which has add/delete buttons.
You can get one by calling
1-800-REMOTES
electricitym
= = = = = = = = = = = =


meirman wrote:
I have a new-to-me 20" Sony color tv from 1989. Is there a way to
preset what channels the channel-up and -down buttons should stop at?

A friend gave this to me and he couldn't find the remote control so I
bought a Sony remote with univeral control for other devices. He
couldn't find the manual either, nor could I for the KV-20TX11

If I use the channel-up button on the tv or the remote, it just adds
1
to the channel number. To go from 13 to 54, I have to press the
button 41 times, or if I can find the remote, press 5, 4, enter.

There is no Scan button that I can find on the tv, and the remote is
not the exact remote for this tv. It was made much later, I think.
(Didn't have it with me but it looked like the Sony remote that Radio
Shack sells now.)

When I press Menu on the remote, the only item that comes up is
"Picture". This corresponds to the controls on the TV. When I open
the door on the tv, there are old-fashioned knobs, pots, for color,
tint, brightness, sharpness, auto-stereo, and cable/no-cable. Only
Picture has up and down buttons!


ALSO but much less important, there are led's on the set for sleep
and
timer. With the new remote, I can set it to turn off in an hour
(Sleep), great.

I am thinking Timer would allow me to have it turn on in the morning.
Is that right? But there is no button for that on the new remote.

Meirman

If emailing, please let me know whether
or not you are posting the same letter.
Change domain to erols.com, if necessary.
Click to expand...
 
some of the universal remotes dont support all functions. you can try
getting a customizeable or learning remote from one for all, and then go
to their website www.ueic.com i think and they have a page for requesting
special device button codes by the tv model number and the code book will
tell you how to customise the buttons. as for the menu? i dont know why
you get a picture menu if this tv has pots for all of the picture
settings, if it has a pot for a control you wont be able to use the remote
to set that option. this may just be a fluke like a technics receiver in
which the universal remote will put it in video 2 mode but i have no video
2 inputs! the special codes will probably give you a way to preset channes
as in some sets there is a special button for add and remove channel. i
find that the list of special button codes is quite good, i have found
options before that even the original remotes never supported.
 
there probably is no way to adjust the settings on the digital volume
control, you could place a resistor on each speaker however this will
decrease the loudest volume possible as well. you would need to match each
one and the value would depend on how much of a volume drop you wanted
 
"BubbaJim" <nobizofyers@where.net> wrote in message
news:Xns95C02750F1E4Ejhester46hotmailcom@38.119.100.153...

....
| I think that the companies stopped giving out repair info on their TVs
....
| Besides, it can take away from a technicians livelihood as well. Look at
| the automotive industry...can you even find the spark plugs on a modern
| car these days?

I can find them but only Dr Zoidberg can get at them.

N
 
"Phil Scott" <philscott888@sf.sbcglobal.net> wrote in message
news:Ji4wd.43131$6q2.26034@newssvr14.news.prodigy.com...

| the contracts are problably arc'd across and stuck on the
| units 'fan control' or fan control relay. ...

More often some 'fiddly fingers' pulled the manual switch out / on.

N
 
Thanks for the reply - maybe I'll just try some duct tape!
Click to expand...

I don't know about anywhere else, but here in England we have a saying.
If someone is talking too loudly or is annoyingly they might be told to "put
a sock in it"

AFAIK the phrase originated in the days of wind-up gramophones or
phonographs.


--
Graham.

%Profound_observation%
 
hi
i have username and password
if you have any ather site panasonic jvc ....
sent me and i sent you sony
thank you
sent me at
sedeco99@hotmail.com
 
"sedeco" <sedeco99@hotmail.com> wrote in message
news:feade178f77611dcbe03c30118757828@localhost.talkaboutelectronicequipment.com...
| hi
| i have username and password
| if you have any ather site panasonic jvc ....
| sent me and i sent you sony
| thank you
| sent me at
| sedeco99@hotmail.com


Where's Porky Pig when you need him?

". . . . That's all folks!"
 
There is no practical way to adjust this. I am aware of this problem in
these models. Most people don't play these sets so low. Usually they run the
line out to sound system, and thus use the volume control on the sound
system.

I would not put resistors in series with the speakers. This will cause a
mismatch between the output stage and speakers. It is not good practice with
these sets.

--

Jerry G.
======


"Joe D" <jdworsky@ix.netcom.com> wrote in message
news:1E_vd.198217$V41.141198@attbi_s52...
Hello all,

Does anyone know how to change how loud the lowest setting is on a
KV-27FS100? For example, on "one bar", it's totally silent, but on "two
bars" it's too loud for late night watching. My other Wega doesn't have
this problem.

I found some instructions for getting into "service mode", but none of
the settings jumped out at me.

Thanks for any pointers,
Joe
 
"Jerry G." <jerryg50@hotmail.com> wrote in message
news:32duauF3jnl9bU9@uni-berlin.de...
There is no practical way to adjust this. I am aware of this problem in
these models. Most people don't play these sets so low. Usually they run
the
line out to sound system, and thus use the volume control on the sound
system.

I would not put resistors in series with the speakers. This will cause a
mismatch between the output stage and speakers. It is not good practice
with
these sets.

--
Click to expand...
Put a resistor in series and another in parallel with each speaker to get it
right, or find a datasheet for the audio amp IC and change a couple
resistors to reduce the gain.
 
mike <spamme0@netscape.net> wrote in news:41C1D27D.8010305@netscape.net:

Sam Goldwasser wrote:
See: http://repairfaq.ece.drexel.edu/sam/hvprobe.htm

Building a voltage divider out of 10, 10M ohm resistors (and suitable
math!) is sufficient and safe.

And if that's what he'd proposed, I probably wouldn't have chimed in
at all. Reread the original post. He said "10 'one meg' resistors in
series". I maintain that the value is too low.
Click to expand...
I agree,and it WILL load the HV circuit.Even a 100 Mohm probe does.
I used 4 22.5Mohm or 9 10Mohm 1/2w precision metal film resistors in series
for a simple probe for a 10 Mohm input Z DMM. It works great.


HV <------[90meg]------[DMM 10meg]-----/gnd

If you do the true divider way,you have to compensate for the DMM input
Z,if you want the probe to be reasonably accurate.

--
Jim Yanik
jyanik-at-kua.net
 
sedeco wrote:
hi
i have username and password
if you have any ather site panasonic jvc ....
sent me and i sent you sony
thank you
sent me at
sedeco99@hotmail.com
= = = = = = = = = = = = = = = = = =
Click to expand...



Great ! I will be VERY happy to send you my username and passwords
for panasonic, jvc, sharp, and many others,
BUT FIRST, send me your PayPal & EBay usernames and passwords.... and
your VISA & Mastercard, account numbers, experation dates and security
codes.
Thank you very much.
electricitym
,
,
,
,
 
Wow..... what a deal. First, send me your passwords and usernames for your
on-line banking and credit card sites.




"sedeco" <sedeco99@hotmail.com> wrote in message
news:39cff2185a8ac364644927cd4cbb00a8@localhost.talkaboutelectronicequipment.com...
i have it sent me anther site and sent you sony
Click to expand...
 
Duct tape is good...... just cover each speaker with it..





"Joe D" <jdworsky@ix.netcom.com> wrote in message
news:MU%vd.198424$V41.77569@attbi_s52...
Thanks for the reply - maybe I'll just try some duct tape!

Joe

AshTray700 wrote:

there probably is no way to adjust the settings on the digital volume
control, you could place a resistor on each speaker however this will
decrease the loudest volume possible as well. you would need to match
each
one and the value would depend on how much of a volume drop you wanted
Click to expand...
 
"sofie" <sofie@olypen.com> wrote in message
news:10s3nki8os7rnaa@corp.supernews.com...
Duct tape is good...... just cover each speaker with it..
Click to expand...
That would look like ass.
 
no kiddin
= = = = = = = = = =


"sofie" <sofie@olypen.com> wrote in message
news:10s3nki8os7rnaa@corp.supernews.com...
Duct tape is good...... just cover each speaker with it..





"Joe D" <jdworsky@ix.netcom.com> wrote in message
news:MU%vd.198424$V41.77569@attbi_s52...
Thanks for the reply - maybe I'll just try some duct tape!

Joe

AshTray700 wrote:

there probably is no way to adjust the settings on the digital volume
control, you could place a resistor on each speaker however this will
decrease the loudest volume possible as well. you would need to match
each
one and the value would depend on how much of a volume drop you wanted
Click to expand...
 
NSM <nowrite@to.me> wrote:
mroberds@worldnet.att.net> wrote in message
news:HCxud.126908$%x.93266@okepread04...

| The reason I was in it was that a cat pissed in it while it was turned
| on, resulting in a totally dead set. ...

What happened to the cat?
Click to expand...
Still alive, so far...

You are a brave, brave man. "Cat pissed in it" = non-fixable in my world!
Click to expand...
Well, I had a live cat, and a dead set. I figured that the worst that
could happen is that I would spend a couple of hours on it, still have
a dead set, and have learned something. As it turned out, I ended up
with a live set.

Matt Roberds
 
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