Toshiba TV29C90 problem; Image fades to black...

[Joe Schmoe]

They won't sell one to me nor will they help.

On Wed, 05 Jan 2005 00:44:11 -0500, Jerry G. wrote:

Have you contacted Hitachi? Most likely you will have to buy the service
manual.

 

[Mark D. Zacharias]

"William R. Walsh" <newsgroups1@saveyourspam.walshcomptech.com> wrote in
message news:Y11Dd.620416$wV.445042@attbi_s54...

Hi!

Thanks to everyone for their excellent tips. I was leaning toward a
shorted
spindle motor, but the fact that the index was always read successfully
made
me wonder if that was really the problem.

Cleaning the lens gave very little improvement and I did make sure it
could
slide back and forth freely. I started in to disconnecting all the cabling
leading to the CD player mechanism and just as a guess, I reseated all of
the connectors before taking the whole thing out to deal with the spindle
motor. I couldn't see anything wrong with any of them, but the player is
working perfectly now. There is no hesitation to spin up now, and the
seeking seems to happen very quickly.

I have never seen a player made quite like this one. It seems that the
spindle motor servo controller is mounted to a circuit board that the
spindle motor is also soldered directly to.

William

Great that it works. I would caution that when repairing CD players, often
one does almost anything and they seem to be fixed, only to have the problem
recur, sometimes weeks or months later.

Mark Z.

 

[Sam Goldwasser]

"Mark D. Zacharias" <mzacharias@yis.us> writes:

"William R. Walsh" <newsgroups1@saveyourspam.walshcomptech.com> wrote in
message news:Y11Dd.620416$wV.445042@attbi_s54...
Hi!

Thanks to everyone for their excellent tips. I was leaning toward a
shorted
spindle motor, but the fact that the index was always read successfully
made
me wonder if that was really the problem.

Cleaning the lens gave very little improvement and I did make sure it
could
slide back and forth freely. I started in to disconnecting all the cabling
leading to the CD player mechanism and just as a guess, I reseated all of
the connectors before taking the whole thing out to deal with the spindle
motor. I couldn't see anything wrong with any of them, but the player is
working perfectly now. There is no hesitation to spin up now, and the
seeking seems to happen very quickly.

I have never seen a player made quite like this one. It seems that the
spindle motor servo controller is mounted to a circuit board that the
spindle motor is also soldered directly to.

William



Great that it works. I would caution that when repairing CD players, often
one does almost anything and they seem to be fixed, only to have the problem
recur, sometimes weeks or months later.

Absolutely! But at least what it confirms is that there is some bad
connection or a crack in the ribbon cable, not likely a component that
is bad.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

 

[reddog2]

If you havent't gotten your manual, I have a SCR-625-C manual (and
detector)(TM 11-1122, dated April 6, 1943) and also a supplement to it
dated 9 December 1944. I would be willing to photocopy them and mail it
to you for $25.00 (US) postpaid if interested.

Robert Russell
USA

Email me at: bobruss@yahoo.com

 

[Colin McCormick]

Dave

After replacing the pinch roller, assuming you find one,
then DO set the azimuth accurately for maximum treble
response when playing a pre-recorded tape in mono lo-fi
mode. If the azimuth is out, recordings you make will
sound horrible on other non-hifi machines, and anyway
you can cause the control pulses to be poorly recorded
causing yet more problems.

The tape riding up as you describe is a common symptom
of a ruined pinch roller.

Colin (www.colin99.co.uk)

davexnet02 wrote:

On Saturday, 01 Jan 2005 23:00:00 -500, "Asimov"
Asimov@-removethis-bbs.juxtaposition.dynip.com> wrote:



Dave, it's never supposed to ride over the edge, only beside it. The
AC head isn't supposed to change top or bottom tension but if the tape
path is wrong then it might. I would suspect wear or an improperly
sitting load arm. Don't mess with the AC unless you are sure the path
is good. I bet you will find it to be okay then.



... This message transmitted on 100% recycled photons.

Hi A*s*i*m*o*v
thanks for the info.
Video and hifi audio alignment is perfect, the two roller guides
that align around the drum have never been moved.

The main problem I have is actually the rubber pinch roller;
I'll have to find a replacement (any sources appreciated)
I seem to have realigned the A/C head to a reasonable accuracy.
cheers,
Dave

 

[jiffypop]

<dggixz@yahoo.com> wrote in message news:Gr%Cd.45228$Yt1.15643@fe08.lga...

please find pictures attached

Its quite obvious that somebody has "photoshopped" these.

 

I would like to thank everyone for their responses. They have been very
helpful. I will check out Hawk this week. Lenny

 

[DaveC]

Thanks, Duff, for your memories : -)

The loading ring doesn't yet come into play. The loading arm (the one that
grabs the tape from the cartridge and brings it way back in the player so the
loading ring can grab it and do its thing) quits halfway through its job.

Some history: the player was working fine, and just unloaded a tape. Wouldn't
rewind (tried but crawled its way through a few inches of tape). Opened it up
and found the supply spindle's brake band material had separated from the
copper backing band. Reglued and reassembled, and now these symptoms.

To summarize: during loading, shouldn't the take-up spindle and the supply
spindle be either locked or free-wheeling (one locked; one free-wheeling)?

In this player, the take-up spindle is pulling (providing some torque), and
the supply spindle is dragging (not locked up, but one or more of the brake
pads or drag shoes is exerting stopping force). This combination seems too
much for the loading mechanism to overcome (nor *should* it try to overcome
it, which might damage the tape).

The brake pads (spring-loaded levers with felt pads) at the supply spindle
are not adjustable, that I can see. I presume that these are either on or
off. Is this correct?

During play, what determines tape tension? Is it the "brake band"
(felt-covered band) wrapping around the take-up spindle?

The brake bands are both loose during loading.

Ideas?

Thanks,
--
Please, no "Go Google this" replies. I wouldn't
ask a question here if I hadn't done that already.

DaveC
me@privacy.net
This is an invalid return address
Please reply in the news group

 

[Amolao]

thanks

 

[none]

Try asking over at rec.video.production, there are alot of pros there
that might know that one.
I'm assuming you don't actually have the cable?
If you can get your hands on a cable and power supply you can reverse
check it.( testing each set of pins on the camera end of the cable
until you find the hot and ground.)
How many pins is the connector on the camera? (10pin , 12 pin etc..)
Give me that and I'll go through my books and see if I can cross it.
If you are adept at repair work you could open up the back case and
check the leads off the connector. They should be color coded, hot
will be red and ground is usually black.
Just visually look for one going to the near edge of the board, this
will usually be the ground, sometines the hot.(there should be a + or
- on the board to indicate which.) just trace down each to get your
power connections.

 

[Joe Schmoe]

Thanks. I'll add that group and give it a try.

I just have the camera. Reverse checking would be simple otherwise. It's a
3pin connector.


On Thu, 06 Jan 2005 20:14:04 -0600, none wrote:

Try asking over at rec.video.production, there are alot of pros there that
might know that one.
I'm assuming you don't actually have the cable? If you can get your hands
on a cable and power supply you can reverse check it.( testing each set of
pins on the camera end of the cable until you find the hot and ground.)
How many pins is the connector on the camera? (10pin , 12 pin etc..) Give
me that and I'll go through my books and see if I can cross it. If you are
adept at repair work you could open up the back case and check the leads
off the connector. They should be color coded, hot will be red and ground
is usually black. Just visually look for one going to the near edge of the
board, this will usually be the ground, sometines the hot.(there should be
a + or - on the board to indicate which.) just trace down each to get your
power connections.

 

[NSM]

"Linards Ticmanis" <ticmanis@gmx.de> wrote in message
news:aaab0ae7.0501062311.7063a1ee@posting.google.com...
| Hello all,
....
| Still, when I record something now with this VCR and then select
| linear audio during playback, it will flutter, at least with music it
| is quite noticable, less so with speech.

How many different brands of tape have you tried?

N

 

[Mike]

In article <e_-dnTo0zYKphk3cRVn-sg@fdn.com>, Avi Frier <avi@noemail.com> wrote:

A few days before the show, I mail a package to the client and ask that they
keep it sealed and bring it to the show.

Two suggestions:

1) Ditch the electronic trickery. With today's technology, it is too easy
for the audience to write this off to a gimmicked recorder. And they'd
be right.

2) Explain what you're doing over on alt.magic.secrets, and that you're
looking for pointers on how to do it so technology is *not* suspected
in quite such an obvious way.

There are many ways of doing similar things involving sealed predictions.

One major way to get the heat off the cassette recorder etc. is to use
a borrowed audio device. Mobile Phone, iPod, cassette player etc. You now
have to think how to get the prediction out of it, without modifying it.

When the trick is over, they can take the cassette home with them-- it will
contain today's headlines no matter where they play it.

This used to be done before people got savvy to FM audio senders, micro
digital recorders etc. The presentation screams electronic gimmickry.

6. For now, I only want one, but we may find a market within the magic
community for more.

I doubt it. It's been done before in the past, and someone somewhere
probably claims designs/patents rights.
--
--------------------------------------+------------------------------------
Mike Brown: mjb[at]pootle.demon.co.uk | http://www.pootle.demon.co.uk/

 

On Thu, 30 Dec 2004 14:53:35 -0500, Active8 <reply2group@ndbbm.net>
wrote:

What kind? I clicked it yesterday and saw an unshaven Santa with a
gun.

I guess a shaven Santa would be more scary for most ;-)

Other than that, I have not noticed anything strange yet.

You just wait *muhahaha*. ;oP

In any case all those virus warnings create more noise than they help!
People should just keep their anti-virus and windows updated - and don't
do obvious stupid stuff ;-)

Clicking a valid url is not that bad, is it? I have no virus checker, never
had. I install the MS patches when I am advised to do so, and that's it.

Those patches won't stop a downloaded malware program you run. That
URL is unavailable now, but I run Antivir and I detected nothing bad
when I visited that link.

See:
http://securityresponse.symantec.com/avcenter/venc/data/bloodhound.exploit.21.html

Geo

 

[Chris Mares]

Chris Mares wrote:

I have a View sonic P815-2M G3 chassis that had no display after turning
it on one day.
Before I started working on it the symptoms were: Power on , power led
is green, relay clicks on, then degauss noise is heard, relay clicks
off, power led goes amber,...then the process repeats continuously with
no display at all.
I have attached a link to a zip file with jpeg schematics to aid in my
diagnostic.

http://members.cox.net/scridmares/p815.zip

After some initial troubleshooting I found Q876 on mainboard open.
(circled on jpeg 59) I replaced it and this made no change to symptoms.
Further troubleshooting led me to another open Q674 on the EHT board
(circled on jpeg 37) so it was replaced also.
Now when tested the monitor will stay in powered led green mode, as long
as an input signal is present but I still have no display. Also the
degauss function has stopped cycling and the clicking relay sound has
become more rapid. When the relay clicks on I can hear about one second
of static build at the EHT board but still no display. The Flyback
almost seems to let out a brief squeal for one second then the relay
cuts out and the process repeats. Two large arc snap sounds came from
the case also, but I couldn't tell from where before they quit. I have
found excessive voltage at ribbon cable supplying EHT board that should
be 195 volts but measures 232 volts. (jpeg 38)
The voltages at base of my HOT are only about 2 volts at best. From what
I make of the schematic I am suppose to have 28 volts there but I seem
to be losing it after T541 (circled in green jpeg 59).
I am guess that the power supply is shutting down due to the over
voltage of 232 volts? I guess my next step would be to get my hands on a
variac to see if I can get it to fully power up by varying the line
voltage. Does this sound like a good next step?
Any help with this is really appreciated as I haven't had my hands into
ant circuits like this since high school.
Thanks
Chris
Does this sound to anyone else like it's the flyback?

 

[SteveB]

As an electronics engineer who works on many types of rather expensive
switch mode power supply (but not PC ones) I believe I can answer your
question. Yes, it could be dried out caps gone low in capacitance or high
in ESR causing an instability, but it can also be a function of the supply
being too efficient for it's own good. When a switched mode supply is asked
to deliver very low output power (i.e. standby) then it has to reduce the
switching waveform width to a very narrow pulse so as to achieve a low
average power output. The pulse width modulator (PWM) IC will only work
reliably down to a certain width pulse which may still be too wide to
achieve the low power required. The result is that the feedback that is
there to maintain a constant output voltage controls the PWM IC by
'chopping' the switching pulses, so you may get a string of pulses followed
by a period of no pulses, then another string of pulses, another gap etc
etc. This isn't too precise, so the number of pulses and gap times varies a
bit; the overall choppiness usually occurs at audio frequencies and can
sound very much like a hissing noise being radiated by the output inductors
or transformers.

A resistor across the standby 5v to waste a bit of power would cure this if
it's the cause, possibly something like 47 - 100 ohms 1 watt but I'm
guessing. A lot of switch mode supplies have a minimum load rating so doing
this is normal practice with a lot of designs anyway. If it doesn't fix it
then I would say change the supply as it's probably a cap failing.



"hupjack" <hupjack_nospamtoday_yahoo.com> wrote in message
news:h7adnaPQc_5EaUTcRVn-3Q@comcast.com...

I absolutely agree with the "safety first" standpoint of fix it before it
causes me havoc, and I didn't have much hope that my description of a
"faint hiss" would give ya'all THAT much to work with.

Definitely what I'm experiencing IS a hiss rather than a whine. Nothing
high pitched about it.. No squeak.. More like a faint rustling....
ssssssssssssssssssssssss

-Ethan

 

[daestrom]

"jiffypop" <jiffypop@yahoo.com> wrote in message
news:41ddbd52$0$62297$39cecf19@news.twtelecom.net...

dggixz@yahoo.com> wrote in message news:Gr%Cd.45228$Yt1.15643@fe08.lga...
please find pictures attached




Its quite obvious that somebody has "photoshopped" these.

And equaly obvious that any '.scr' file probably contains a virus. Did you
disinfect it before you viewed it??

daestrom

 

Units exposed to water can have all sorts of weird problems occur,
especially in electromechanical devices like cd players where there are
very fine tolerances. Impurities deposited by the water , grit etc. can
find their way into connectors, transformers , and almost all other
places. If the unit is left as-is, corrosion and other problems can set
in.

Faults can take time to appear, even when the player has been dry for
considerable time. I have found that dismantling the device totally (as
soon as you get it away from the damp before rust sets in!), drying,
re-lubing, checking all areas for deposits and cleaning can minimize
the risk of problems. As you have found, reseating connectors is at
least a good place to start!

-
Ben

 

[Harvey]

"MIke" <lescault91967@aol.com> wrote in message
news:crldqd$1kf2$5666@news.utel.net.ua...

MAKE LOTS OF MONEY QUICKLY, GUARANTEED 100%, NO SCAM!

Yeah right, we all believe you... really we do...

Mail the 6 envelopes to the following addresses:

#1 John Christensen 5446 Santa Barbara Sparks, NV 89436
#2 Randall Hines 22 Stature Dr. Newark DE 19713
#3 Mike Sharrer 921 West State St. Coopersburg PA 18036
#4 Travis Montgomery 2211 Elmers Lane Norfolk NE 68701
#5 James Adair the third 22 Over Rd. Feasterville PA 19053
#6 Michael Lescault 123 Rhode Island Ave. Pawtucket, RI. 02860

I have to wonder as the intelligence of some people, especially those who
spam newsgroups, giving away not only their email address, but also their
full postal address as well.

Somehow I get the feeling Mr. Michael Lescault is going to be having a few
'interesting' visits over the next few days.

 

On Thu, 6 Jan 2005 16:36:01 -0600, "jiffypop" <jiffypop@yahoo.com>
wrote:

dggixz@yahoo.com> wrote in message news:Gr%Cd.45228$Yt1.15643@fe08.lga...
please find pictures attached


Its quite obvious that somebody has "photoshopped" these.

Digital surgery??


Geo