Toshiba TV29C90 problem; Image fades to black...

The resistors most likely to go bad are the low value ones close to the IC's
(usually 1-10 Ohm 1/2 or 1 watt). Did replacing the IC's giva any improvement
at all? Hitachi's have had problems with the Digital Convergence Unit.
Replacing the IC's won't help with this problem.
 
..... or just MAYBE it is a "Hotel" model that would require the "master
remote" to change these settings.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"Bill Jr" <bill@nospam.usa2net.net> wrote in message
Sounds like a bad eprom. Or maybe backup battery, if that old.



"Chris F." <zappymanREMOVETHIS@hotmail.com
Got this '91 Magnavox 26" stereo TV, it's been for sale in my shop for
some time, but I've noticed something that might be a minor annoyance.
Every
time the set is powered, it goes back to channel 3 and the display
language
changes to Spanish. Doesn't matter if the set is left plugged in or not.
Any
ideas?
Click to expand...
 
Interesting idea, but video monitors aren't designed to handle that sort of
thing. Your typical vertical deflection circuit is designed to work at 60
Hz, and the horizontal deflection circuit wants to run at 15.7 kHz (or even
twice that frequency, if it's a VGA monitor). Going too far beyond those
boundaries creates all kinds of hellacious noise, and/or fried components.

It would probably be easier to use a cheap X/Y oscilloscope instead. They
are designed to handle just about anything, and you can plug your stereo
outputs directly into the 'scope inputs with no trouble at all. Any
adjustments for optimum picture can be done right there from the front panel
of the 'scope.
 
<reverend_rogers@yahoo.com> wrote in message
news:1107479174.064467.5290@g14g2000cwa.googlegroups.com...
I am trying to find an "artistic" use for a few old computer monitors

oscilloscope". NO, I don't want to do that, but rather make an audio
display, driving the yoke with a stereo amp to move the beam around the
Click to expand...
You can't drive a yoke with audio and it makes no sense. You could just
figure out the connections and hook the L and R to two of the color inputs
but it'd be kind of crappy. I'd look for a circuit to do this from maybe
Elektor or Silicon Chip (two magazines).
--
N
 
dennis Wrote:
Can someone tell me the watts per channel of this Amp?

Thanks
Click to expand...
The Kenwood KA 8004 has 2 x 85 watt
I had this Amplifier in the seventees.
I stil have the Tuner KT 8005

Kjell Erik Nilsen - Norway !


--
Kjell Erik Nilsen
 
Can't help you, but suggest you also do your search using Lucent
Technologies and Agere Systems since AT&T MicroElectronics became Lucent,
then Agere after spin offs in 1996 and 2001 respectively. If I had to
guess, I'd say it is a Physical Layer Ethernet communications or control
chip since this is what AT&T ME specialized in.

Good luck.

Bob

"William R. Walsh" <newsgroups1@saveyourspam.walshcomptech.com> wrote in
message news:F6yMd.48348$eT5.21015@attbi_s51...
Hello all...

The above-mentioned IC is used on an Ethernet adapter that I have here.
The
adapter works just fine. I am just curious what this IC does. So far I
have
been unable to locate any information on it. What I'd really like to find
is
a datasheet or description of its function.

Thanks!

William
Click to expand...
 
"CJT" <abujlehc@prodigy.net> wrote in message
news:4202EB63.1090704@prodigy.net...

Ever hear of Lissajous figures?
Click to expand...
Yup. And you can't drive a yoke with an 8 ohm speaker output. It takes some
serious amps. And you can't vary the frequency by very much either.
--
N
 
On Fri, 4 Feb 2005 00:56:48 +0100 "David Winter" <d_winter@hotmail.com>
wrote in Message id:
<4202b987$0$4800$79c14f64@nan-newsreader-05.noos.net>:

[sci.electronics.repair & sci.electronics.components added]

Hello,

I can't find anything about those early PROM chips which are used on a
circuit board I need to fix.
Click to expand...
What board?

I need their pinout, if anybody knows where I can find them that would be
great.
I tried chipdir and similar sites but no luck, they only tell me that one is
a 256*4 PROM and the other a 512*4 PROM (we are talking in bytes, not
kilobytes, megabytes or gigabytes).
These chips date the 1970s.
Click to expand...
Are the numbers C3601 & C3602 reference designations on the PCB, a label
on the chips themselves, or the part # located under the label? The part
number under the label is what's most important. Be aware that if these
*are* programmable, and you need a replacement, you may be in for a
difficult time.
 
On Fri, 04 Feb 2005 05:34:29 GMT "NSM" <nowrite@to.me> wrote in Message
id: <FPDMd.303$rB6.170@edtnps91>:

"CJT" <abujlehc@prodigy.net> wrote in message
news:4202EB63.1090704@prodigy.net...

Ever hear of Lissajous figures?

Yup. And you can't drive a yoke with an 8 ohm speaker output. It takes some
serious amps. And you can't vary the frequency by very much either.
Click to expand...
FWIW, I did exactly that about 20 years ago on a color RCA tube chassis
that had a deflection problem. Disconnected the yoke from the chassis and
used the left channel to drive the horizontal and the right channel to
drive the vertical. The patterns would fill the screen at about 3/4 volume
using a 50W per channel receiver. It was quite the hit at parties.
 
On Fri, 04 Feb 2005 06:02:01 -0500, Jay <none@dev.nul> wrote:

On Fri, 4 Feb 2005 00:56:48 +0100 "David Winter" <d_winter@hotmail.com
wrote in Message id:
4202b987$0$4800$79c14f64@nan-newsreader-05.noos.net>:

[sci.electronics.repair & sci.electronics.components added]

Hello,

I can't find anything about those early PROM chips which are used on a
circuit board I need to fix.
Click to expand...
Well, those sheets are in Intel's data catalog.
(OK, it's the 1976 edition, but still :)

e-mail me if you need them
--
Kind regards,
Gerard Bok
 
Thanks for the responses.

Seems like the older sets were far more forgiving when it comes to
disconnecting the yoke.

I have already tried using the vertical of the 9" mono monitor, which
produced a result, but as JW posted, you need a fair bit of volume to
do it.

I haven't yet tried the horizontal. Will look at the option of an
inductor and series load. and also look out for the magazine circuits
NSM suggested for the colour.-

will post with results at a later stage!

regards, Ben
 
In article <dcOdnehba7JHdJ_fRVn-jQ@comcast.com>, Scott McDonnell
<NetSamurai@comcast.net> writes
Georges,
Thanks for the reply!

I believe they are random. They are normally quite far between,
but are very loud and annoying. It's more like a "pop" though,
but with a very short crackle sound after the pop. At first it
Click to expand...
In another post you say it's fed from a digital satellite receiver. A
dropout or error burst in the satellite signal will make exactly that
kind of noise. Could be the antenna/dish has moved or the cable is
getting water in it or something.

I'd try feeding it from another source for a few hours (days?) and see
if that fixes it.
--
Tim Mitchell
 
Needs a complete mirror and lens cleaning AND all the coolant needs
replaced in the picture tubes after they are disassembled to clean the
growth of years of crud that is on the face of the tubes. Strongly
recommend you have someone do the job who has access to all the
training, parts, and experience to do the job properly. Typically
under a $250 total repair depending on how badly the adjustments have
been screwed up.

David
 
You need to follow the gray scale adjustment procedure in the service
manual for the set. Odds are that set uses some form of AKB and auto
color tracking so you need to apply the correct signal from the
generator and adjust it per the service manual. The set may need a
full check out of the screen voltage, bias levels, and drive levels,
then the color decoder levels will need checked.

David
 
<reverend_rogers@yahoo.com> wrote in message
news:1107523042.555960.14840@l41g2000cwc.googlegroups.com...
Thanks for the responses.

Seems like the older sets were far more forgiving when it comes to
disconnecting the yoke.

I have already tried using the vertical of the 9" mono monitor, which
produced a result, but as JW posted, you need a fair bit of volume to
do it.

I haven't yet tried the horizontal. Will look at the option of an
inductor and series load. and also look out for the magazine circuits
NSM suggested for the colour.-

will post with results at a later stage!
Click to expand...
I recall the Radio Shack Color Computer had an optional ROMPak which did
various displays like those in Media Player software when you hooked it up
to your stereo. They even claimed you could tune your room with it - a bit
dubious I think.
--
N
 
I am an owner of a PFM 500A3WU with the exact same problem.

And it wasnt dropped, just moved carefully form location ot location.

All my research tells me the panel would need to be replaced. And with
sony this is VERY cost prohibitive, especially when you factor in the
cost for new EDTV 42" plasma displays and the 500A3WU is a first
generation plasma.

Very dissapointing especially when dealing with Sony service.

If you ever find a solution please post. But I think you and I are both
out of luck and a plasma TV poorer (luckily for you yours was free)


--
rxkeven
 
dkuhajda@locl.net wrote:
You need to follow the gray scale adjustment procedure in the service
manual for the set. Odds are that set uses some form of AKB and auto
color tracking so you need to apply the correct signal from the
generator and adjust it per the service manual. The set may need a
full check out of the screen voltage, bias levels, and drive levels,
then the color decoder levels will need checked.

David
____________
Click to expand...
Thanks for replying. In addition I forgot to mention that this set has
non-defeatable SVM. Has that been known to smear the picture in some
cases? And would disconnecting it internally allow for a more
adjustable picture?

-CC
 
Send the measurements of the screen, I have a few kicking around.

It also may be ready for a coolant change.

JURB
 
You'll need a spare yoke and stepup transformers to match impedance. Set the
original yoke aside still hooked up and put the spare on the tube. To use a
computer monitor you may need to have an old PC just to get it to turn on.

In fact, to set the purity you'll need to feed the monitor all one color from a
PC, then you can interrupt the video signal and start playing around with that
too, use a low value cap fo example to feed the high frequencies to modulate
the beams.

(yes, as you suspect I have done it, on an old 21" round color TV)

Have fun.

JURB
 
In article <6qKdnWXH4Il5Lp3fRVn-gg@comcast.com>,
Scott McDonnell <NetSamurai@comcast.net> wrote:
Hello,

My father owns a few resturaunts and these use 70V commercial sound
systems for the background music. In one of his stores, the speakers
are making a crackling or popping sound all of a sudden. He asked me
to change 3 speakers (they were in quiet areas where it was most
noticeable so he thought that was all it was) and the problem is
still there, even in the new speakers. I started suspecting the 70V
amplifier. He had a spare one, though it was used and about as old,
so I installed that one to see if there was a difference. The
crackling was still present. Anyone have any ideas what to check
for?

So far, I have tried:
replacing a few speakers
tried a different, but not new, 70V amplifier
tried different wattage settings at the speakers
tried to adjust the volumes on both amp and source
balanced bass and treble

None of this seems to work. I do have an oscilloscope
and know how to use it, but have not had a chance to
bring that with me and look at the signals. Any suggestions?
Click to expand...
Using my theory of maximum inconvenience, it'll be a simple problem
in the hardest part of the system to fix. The wiring in the walls.

Is there a remote volume control panel? If it's on all the speakers,
it sounds like an intermittent on the input side of things. Or pickup
of radio transmitter. (Any highway patrolmen radioing in after they
finish lunch?. Somebody on the other side of the wall running real
estate deals on his cellphone)?

Mark Zenier mzenier@eskimo.com Washington State resident
 
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