Toshiba TV29C90 problem; Image fades to black...

[George Neuner]

On Tue, 8 Feb 2005 20:22:25 -0600, "Mark D. Zacharias"
<mzacharias@yis.us> wrote:

The switch is stand-up mounted on a circuit board underneath the pickup.
Kind of hard to get to.

Mark Z.

Thanks. I'll see if I can get a look at it.

George
--
for email reply remove "/" from address

 

[BOB URZ]

N Cook wrote:

Anyone else's contributions.
I was reveiwing my collection of test kit repair breifs and
re-read this one
"Eventually found ( problem with 'scope power supply )
the O/P was being loaded by a faulty opto-isolator that
gates the beam current. It was ohmic between I/P
and O/P so removed and cracked open with mole grips
(vice grip locking pliers). Looking at the transparent
bridge under a 30x microscope there were tiny circles of
mold or fungus that had grown and coalesced forming
a resistive bridge between I/P and O/P."

While on the theme. Has anyone else come
across old kit with conformal coating over everything
that appears to have chemically broken down to an oily
consistency that then seeps into ICs corrupting them

electronic hints and repair briefs , schematics/manuals list on
http://homepages.tcp.co.uk/~diverse
test kit repairs file
http://www.divdev.fsnet.co.uk/repair4.htm

Was working on a old hitachi VCR once. The mech control buttons
were messed up. Some did nothing at all while the others did functions
other than what they said. That was a real puzzler. This keypad used a
resistor matrix for a voltage divider to determine which key was
pressed. Upon closer inspection, a hard sugary material was found on the
circuit board. Turned out someone spilled oatmeal with plenty of sugar
on it into the vent holes on the top of the unit. This dripped down on
the circuit board by where the front panel plugged in. The crystallized
sugar added enough resistance to screw up the function by added
additional resistance to the lines to ground.

I had a car stereo amp once which had voltage on the ground of the RCA
input jacks. i had the unit on the bench with a AC powered
cassette deck as a source and all was fine. All rail voltages were
OK. But when you hooked up a car stereo type input on the same 12 volt
ground things would spark and wack out. Turned out the torroid
switching transformer was shorting out a primary winding to the
shield below which was a shield for the secondary low volt supplies.
The end result was this effectively put 12 volts on the shield of the
RCA input jacks. Lifting the torroid and a well placed insulator over
the nicked winding solved the problem.

Bob



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[Deke]

<RonKZ650@aol.com> wrote in message
news:1107978809.188283.3810@l41g2000cwc.googlegroups.com...

I've worked on a few sets filled with dead cockroaches. I always
thought it would be great to be able to tell the customer when they ask
"What was wrong with it" to truthfully say "Cockroaches were all over
in there and shorted out the electronics". Unfortunately removal of
dead roaches never actually helped fix any of these sets :-(

You mean you actually go ahead and work on them?
Our SOP is to put them in a large garbage bag, spay a bunch of RAID in the
bag, then seal the bag. We then call the customer and tell them we cant
work on it because its full of roaches, we dont want to infect our shop, and
please come and get the unit. Its given to them, still in the bag, and they
are advised not to bring it back. Cheaper to refuse the service, than to
infect your shop, and have to fumigate.

 

[da_test]

On Thu, 10 Feb 2005 03:39:48 GMT, "James Sweet"
<jamessweet@hotmail.com> wrote:

It's not entirely uncommon to find a set like this with a bad CRT, that's
probably your best bet. I've found a similar one once that had been dropped
so the CRT was broken.

how did you find it?

Were you driving around the neighborhood and saw it
sitting on the curb side?
Did you place an ad?
Cheers,
Dave

 

[James Sweet]

"da_test" <davexnet02NO@SPAMyahoo.com> wrote in message
news:skpl015r1ckn7hp99r928pi41pc18faif7@4ax.com...

On Thu, 10 Feb 2005 03:39:48 GMT, "James Sweet"
jamessweet@hotmail.com> wrote:



It's not entirely uncommon to find a set like this with a bad CRT, that's
probably your best bet. I've found a similar one once that had been
dropped
so the CRT was broken.

how did you find it?
Were you driving around the neighborhood and saw it
sitting on the curb side?
Did you place an ad?
Cheers,
Dave

I found it next to the dumpster at the apartment complex I lived in, I've
also gotten free broken TV's from ads on craigslist, there's many places you
can look.

 

[Time]

The symptoms weren’t exactly the same. As I said, the CD player originally
stopped working because I was too rough while cleaning the lens, and that
seems to be exactly how the old unit acts; it spins the CD up, takes quite
a while looking and eventually just shows 99-99 on the display, it can
detect the CD (it also knows when there is no disc inserted) but just not
properly, as if the lens is damaged or scratched.

With the replacement; it usually doesn’t even spin the CD up, it just
gives a pathetic little spin and then says ‘Er’ as I said.

I don’t like the idea that this new unit could have been DOA, i went to
quite a lot of effort (not to mention the $$) to get it, how could I rule
this in/out?

-I am quite sure the laser is getting power a red light shows up on my
digital camera display, so I think ill stay away from adjusting laser
power.

-I think the unit is mechanically sound, it moves through all the right
axes, although I'm not sure why it doesn’t spin-up CD's correctly.

-And the unit at least attempts to focus; the lens bobs up and down under
the CD.

Do these symptoms make any sense?

 

[Tim Kett]

Comboverfish <comboverfish@yahoo.com> wrote in article
<1108006767.053298.200090@g14g2000cwa.googlegroups.com>...

You have some common GM truck stereo issues here. Here is how they are
repaired normally.

You *can* get backlight bulbs for the radio buttons at the GM dealer.
I don't know how they are sourced otherwise. They will be expensive,
according to an authorized Delco radio repair shop owner I talked to
last year.

Suitable substitutes can be had cheaper, almost definately BUT *you are
totally right about the CD player* ! Its scrap ! At 1995, I would just
throw an aftermarket in it, but your suggestions are easier for the novice.

The CD player isn't worth attempting to "diagnose". It probably either
doesn't power up, or displays an error message. You can get a
remanufactured CD player exchange either at a local Delco rebuilder
(cheapest best option) or at the Dealer (same thing but marked up) or
through places like Ebay which are expensive but require no exchange.
Used units are available on Ebay but I wouldn't think of going that
route. They want over $100 for an ungaranteed used player -- no
thanks!

Toyota MDT in MO

 

[Erik]

Anyone?

 

[J. Doe]

Deke wrote:

You are kidding, right?

Leonard


Not at all. Are you saying you like working on stuff full of
roaches? We dont, and wont.

I had the same experience with a CB radio. Took the lid off on the work
bench and couldn't believe what I saw! It looked like a bowl of cereal,
only most of the corn flakes were alive! About the time they realized it
was freedom, several took off across the bench before I slammed the lid back
on, took it outside and hit it with bug spray, put it in a sealed bag, and
returned it to the customer with the warning - DO NOT open this in your
house or car. How the roaches got in there in the first place is amazing,
since the only opening was the 1/8" speaker jack. A couple of baby roaches
must have went in that way and set up house. Can't believe they actually
muliplied to the point of no more space, with no food or water.......

 

[Doug]

We repair these units. I assume you are talking about an AM/FM/Cassette
unit with a remotely mounted CD deck. The lamps are Delco #16189302,
there are ten of them and it's best to replace all. They cost more than
you might expect.

The CD drives are normally a Panasonic product. The motors and pickups
are available from Panasonic, but you have to know where to find the
part numbers. All bets are off, however, if there has been electrical
damage from the loose change in the unit. If it uses the most common
Pana mechanism, the most frequent failure we've seen is the pickup. The
scenario is that the disc loads, spins while focus is attempted three
times, then ejects. This is typically about a $140.00 repair.

To service your unit the CD player must be connected to a compatible
host radio and a power supply. It's not a beginner's job. Check around,
I'm sure someone will at least check it out for you.

Good Luck.

 

Remembered another strange fault.
Car tape player, so no record function, but every tape
that was played in it got an overlaid recording
of the click you get with a vinyl LP playing at 33 rpm.
Permanently recorded on commercial tapes that
had the 'write protect' tabs activated. Play the tapes on
any other machine and the clicks were permanently there.
I'll leave that as a teaser , in case anyone can
fathom the fault, before I reveal tomorrow.

electronic hints and repair briefs , schematics/manuals list on
http://homepages.tcp.co.uk/~diverse

That would have to be a small magnet that had gotten inside on some
rotating part, or a rotating part had became magnetized, that contacts or

goes near the tape.
MVB

 

hillelg123@yahoo.com wrote:

In 10-30-2004 I bought a new 27' Panasonic TV, CT27SL14.
In 2-8-2005 the TV *died* in the middle of a program. No picture,
no sound, no light on controls, no nothing.

If the fuse has gone, it is probably due to some other fault, often in
the power supply. It is unlikely (but not impossible) that the fuse
just died.
If the fuse is blackened, there is a critical short. As a general rule,
if the wire inside it is just broken, it could be less serious.

However, why mess about? I say take it back to the shop under warranty.
They ought to just give you a new one, its barely 3 months old !!! My
folks had to do this twice about 15 months ago, and they got an new set
each time no quibble. (ASDA, UK)
-Ben

 

[Tony]

I really don't like the direction this group has taken over the past
few months. People here have become far too criticising to new
posters.

I'm also tired of the bad spelling and grammar - some posters are
bordering on illiterate.

Good bye.

Tony.

 

N Cook wrote:

Remembered another strange fault.
Car tape player, so no record function, but every tape
that was played in it got an overlaid recording
of the click you get with a vinyl LP playing at 33 rpm.
Permanently recorded on commercial tapes that
had the 'write protect' tabs activated. Play the tapes on
any other machine and the clicks were permanently there.
I'll leave that as a teaser , in case anyone can
fathom the fault, before I reveal tomorrow.

A click rather than partial erasure?

racked my brains, all I can think of is:
- something metallic in contact with the capstan/pinch roller
- some kind of spool motion sensor magnet got shifted out of place????
- head leads somehow got shifted near something like an intermittent
solenoid, induced current into them/ picked up strong parasitic
signals???? (cue sound of scraping of bottom of barrel)
-B

 

The warranty for *parts* is one year, but for *labor* is 90 days.
I checked the date, it died after 100 days. (My previous TV died
after 4000 days, but it was bought before the days of super-advanced
electornics.)

Anyway, I never open any appliance before I
1) Disconect the power cord.
2) Wait several minutes.

 

One month old display implies it's brand new. Gotta be under warranty.
Contact the "authorized service center" indicated in your point of sale
paperwork. Why would Sony tell you to use a different tech instead of
asking you to contact the retailer about unsatisfactory service? I
would demand the problem be corrected by a competent tech, or have the
set replaced. Trust me, cause enough stink, they will be glad to bend
over backwards to get rid of you. Now back to your original
question.....I am a beginner in repair, but I would start in a place
that is common to all inputs. A faulty component in the power supply is
possible. A bad supply is one that costs more money to repair than
replace.

 

[Harvey]

"Tony" <me@privacy.net> wrote in message
news:nhrn01tf1r5tu2ts8tfh52m8rnqeiv17l7@4ax.com...

I really don't like the direction this group has taken over the past
few months. People here have become far too criticising to new
posters.

I'm also tired of the bad spelling and grammar - some posters are
bordering on illiterate.

Good bye.

Tony.

So why did you set the follow-up's to uk.local.yorkshire.moderated?

I guess your either a troll, or a twat.

 

The probability that it is JUST a fuse is slim, probably about the same
as you winning the lottery. The only way to know what is going on is
for a full and proper diagnosis by a trained technician.

Odds are they are not going to overcharge you for the repair required.

 

[what]

The posts from folks who get their feelings hurt over newsgroup comments are
always hilarious. Simply ignore what you don't want to read. It's not hard
to do. Start living in the real world. Leaving this group is your own fault.

"Tony" <me@privacy.net> wrote in message
news:nhrn01tf1r5tu2ts8tfh52m8rnqeiv17l7@4ax.com...

Good bye.

Tony.

 

[DavidHi]

Thanks for the reply. Yes, it is brand new. I'm going to see what
this tech says --- if it's the same type of thing, I will probably go
the route of replacing the set.