Toshiba TV29C90 problem; Image fades to black...

Yeah, you've got it there. The trimmer is for the freq. shift,
according to a tech who works on it. I'll have to do that next. :) I've
got the right transistor.. it looks like I'll have to adjust the
inductors, but there're 3-4 of them and I have no idea what they do.
The project kind of got sidelined anyway.


Daniel wrote:
stickyfox@gmail.com a écrit :

FWIW.. not that it helps:

144 MHz is the American 2m ham band, for which I have a license.. I
left that out. It's not exactly in the band plan for RC aircraft but
it's not like I'd be causing real aircraft to plummet to the earth.

Thanks for the tip about capacitance. There is a trimmer cap on the
board right next to the crystal, I assumed it had something to do with
tuning the feedback but I don't even know what kind of oscillator it
was so I was hesitant to just start twisting knobs.


It is very difficult to get schematics/ service manual in the RC hobby.
Some kind of trade secrets, maybe.

Probably the trimmer cap is there to adjust the frequency shift at
+/-1.5kHz from center frequency. This is the FSK system used in RC
equipments.

Did you used the correct replacement transistor?

Try posting on http://groups.google.com/group/rec.models.rc.air .


Daniel
Click to expand...
 
On Mon, 04 Dec 2006 20:13:48 GMT, Jumpster Jiver <me@no.spam.today>
wrote:

:Dan_Musicant wrote:
:> One of my two S-VHS recorders has this problem, an RCA VR695HF. I bought
:> it about 1990. It was one of the earliest S-VHS decks. I also have the
:> earliest one, a JVC JRS-7000U. Both decks have been repaired a few times
:> - the heads have been replaced.
:>
:> The RCA deck has had a problem for a while. It doesn't always eject the
:> tape. I press the eject button and I hear the mechanism kick in but the
:> tape doesn't eject. Until a couple weeks ago, it usually (not always!!)
:> ejected on the second press (the same sound happened both presses, but
:> the second time the tape came out). A couple weeks ago I had to press it
:> 40-50 times before the tape finally came out. Annoying, especially
:> because the tape was due back at the library that day.
:>
:> Some months ago I took the cover off and looked for something to adjust
:> or lubricate but whatever I did didn't help (cleaned, a bit of
:> lubrication here and there, blow compressed air, etc.). Using a
:> different tape has no evident effect.
:>
:> Any ideas what I might look for in troubleshooting and fixing this
:> problem? I have a book on repairing VCR's, but its flowcharts haven't
:> helped.
:>
:> Thanks!
:>
:> Dan
:I believe you need to replace the entire right (gear driven ) side of
:the cassette carriage. This was a common repair on RCA VCRs.
:I think you can still find it if you ask a parts distributor.
:Sorry I don't remember the part number.

If I order the part, will it be fairly evident how to do the
replacement? Thanks for the help!

Dan

PS Is the part interchangeable between different RCA VCR's? IOW, if I
find a used one? Thanks!
 
stickyfox@gmail.com wrote:

FWIW.. not that it helps:

144 MHz is the American 2m ham band, for which I have a license.. I
left that out. It's not exactly in the band plan for RC aircraft but
it's not like I'd be causing real aircraft to plummet to the earth.

Thanks for the tip about capacitance. There is a trimmer cap on the
board right next to the crystal, I assumed it had something to do with
tuning the feedback but I don't even know what kind of oscillator it
was so I was hesitant to just start twisting knobs.
Click to expand...
I doubt that has anything to do with it, all those do is pull the xtal
slightly. Could be wrong tho.

You'll nrace the cct diag for the osc, and tweak or even add some rc
somewhere



NT
 
nucleus wrote:

does your operating manual suggest using a microwave oven to heat
plates?

a microwave oven is designed to heat items containing water. a water
molecule is composed of a single atom of oxygen with two atoms of
hydrogen attached at a specific angle to the oxygen atom. the
frequency
of a microwave oven is designed to cause the hydrogen atoms to
vibrate, causing friction with adjacent water molecules, thereby
generating heat.

clays contain minerals rich in metal oxides. the metal in your plates
possibly has been marginal in the past and due to usage, the addition
of molecular metal particles from flatware may have caused the change.
Click to expand...
Nukes are nothing like that fragile. You can heat plates in them, melt
aluminium & iron in them, or put metal foil on food in them. The
problem is just lack of load, the plates dont absorb much, plus burnt
muck on the waveguide entry cover.

Contrary to myth, magnetrons are not killed by running them with no
load, that only applied to the very first commercial microwave oven
iirc. However it does tend to cause arcing, and that can do minor
damage in the cooking cavity, the worst example of which is frying that
plastic plate. Once theres carbon on that, it will deteriorate until it
catches fire. So keep that lil cover clean.


NT
 
nucleus wrote:

does your operating manual suggest using a microwave oven to heat
plates?

a microwave oven is designed to heat items containing water. a water
molecule is composed of a single atom of oxygen with two atoms of
hydrogen attached at a specific angle to the oxygen atom. the
frequency
of a microwave oven is designed to cause the hydrogen atoms to
vibrate, causing friction with adjacent water molecules, thereby
generating heat.

clays contain minerals rich in metal oxides. the metal in your plates
possibly has been marginal in the past and due to usage, the addition
of molecular metal particles from flatware may have caused the change.
Click to expand...
Nukes are nothing like that fragile. You can heat plates in them, melt
aluminium & iron in them, or put metal foil on food in them. The
problem is just lack of load, the plates dont absorb much, plus burnt
muck on the waveguide entry cover.

Contrary to myth, magnetrons are not killed by running them with no
load, that only applied to the very first commercial microwave oven
iirc. However it does tend to cause arcing, and that can do minor
damage in the cooking cavity, the worst example of which is frying that
plastic plate. Once theres carbon on that, it will deteriorate until it
catches fire. So keep that lil cover clean and you can cast iron in it
in peace.


NT
 
"N Cook" <diverse8@gazeta.pl> wrote in message
news:fd8834$cgo$1@inews.gazeta.pl...
Arfa Daily <arfa.daily@ntlworld.com> wrote in message
news:OFMJi.37428$Db6.1245@newsfe3-win.ntli.net...

"N Cook" <diverse8@gazeta.pl> wrote in message
news:fd7tdb$s5d$1@inews.gazeta.pl...
No movements or laser light , totally dead CD player. Just -- in the
display.
Function sw and door latch sw ok. Plenty of 5V etc supplies around on
the
chippery. Crystal and ceramic resonator have oscillation.
All 4 channel motor/focus driver o/p at 3.8V, all 4 inputs at 2.1V,
disable
is set off ie operational.
Pressing all sm chip leads , no change
Swapping laser and carrier/motors section with another one laying
around,
the same zilch. No dodgy electrolytics.
Is there something obvious I'm overlooking ?
Not worth spending a lot of time on but a good customer for other
stuff.


Can't think of anything that you seem to be overlooking. First place I
would
have gone is the same as you - to the door switch. Even though the switch
is
working ok in itself, I would still feel inclined to make sure that its
connections are making it all the way back to the micro, and doing
something
ie pulling a pin to ground or whatever. I've had internal pull-up
resistors
on micro pins fail. The only other thing that it's worth doing when all
else
has failed, and you've given up, is to try a possible 'real' system
reset,
by holding in the power button and applying power, and if that fails, a
'naughty' engineer's reset, by turning off and removing power, then
hooking
a croc lead to ground, and stroking round every pin of every 'micro-ish'
IC
both on the front panel, and the CD process board. I've known this to
restore screwed up system controls on a number of occasions. I got it
originally from a manufacturer's training course, but so far back in the
dim
mists of time, I can't remember which one now ...

Arfa



Perhaps stripping off at midnight and dancing around it on a full moon
might
work as well.
Click to expand...
Only if it's a Philips ...

Arfa
 
check for goo on the spindle clamp.



"Videlectrix" <bcgobraves@gmail.com> wrote in message
news:1165437554.717121.122040@j44g2000cwa.googlegroups.com...
I have a problem with the 3-cd changer component of an Aiwa all-in-one
system. The problem is that the player keeps leaving a mysterious
residue on CDs, always at the same distance from the center and no
matter which position (1/2/3) the disc is in the tray.. The residue
comes off OK but seems to be slightly abrasive as sometimes removing it
leaves small scratches on the CDs. I have tried cleaning the lens and
the tray; if this has any effect it is only temporary as this problem
has been going on for some time now. Any insights would be appreciated!
Click to expand...
 
"Elle" <honda.lioness@nospam.earthlink.net> wrote in message
news:eaBdh.7036$sf5.5814@newsread4.news.pas.earthlink.net...
My ten-year-old television's display is mighty snowy much of the time
(when receiving local channels), until I give it a good whack and I guess
cause some connections to work properly again.
Click to expand...
Stop whacking it and undo and then redo the antenna connections.
 
C4306 and C3478 measure extremely high in ESR. and C3406 is 100uf and a new
one reads near 0 ohms, while the one in teh circuit reads near 50ohm.

so its bad. but would this cause the dead set symptom?



"Mike" <nospam@microsoft.net> wrote in message
news:REFdh.2111$SJ3.813@tornado.ohiordc.rr.com...
I got this set, it was totally dead, relay clicks. now its completely dead,
no relay click.


I tested the fuses, and tested the HOT, they test fine. Im going to run an
ESR check on the caps to see if i spot any bad ones.

The solder joints appear they have been redone in the past. so thats not
the issue.

any ideas?
Click to expand...
 
Elle wrote:
My ten-year-old television's display is mighty snowy much of
the time (when receiving local channels), until I give it a
good whack and I guess cause some connections to work
properly again. It's humongous and so hard to move by
myself. I am getting old and do not want to have to move it.
Rather than try to repair it, I am thinking of buying a new,
lighter, flat screen TV. I have been keeping an eye peeled
for specials at Circuit City, Best Buy, and Wal-Mart. I
looked at the latest Consumer Reports article on the
subject.

Yesterday at Best Buy a clerk there said buying any of the
flat screen TVs meant I would have HDTV. Without cable or
satellite with HD, the display would have black vertical
bars covering something like three inches on both sides. If
I wanted to continue using an ordinary antenna, I'd have to
go to a conventional TV with a 4:3 aspect ratio.

Can someone please confirm or deny what the clerk said and
maybe elaborate? Meanwhile I am googling on the subject.

I do not want cable or satellite or any extra costs. OTOH, I
also do not want a huge television to move around.

TIA
Click to expand...
so you're going to ditch an otherwise usable Tv for want of a bit of
resoldering on the tuner?? sounds wasteful to me. why don't you just
fix it? or get a tech on the case?
besides, when fixed up well it will probably outlive any of the crap on
sale today, to say nothign of the sharper picture CRT gives over plasma
and LCD smear-o-vision.

I'd give it a second chance if I were you!
-B.
 
"Jake" <gl1000gold@yahoo.com> wrote in news:1165436075.632350.204050@
80g2000cwy.googlegroups.com:

hello all, I've been searching for a schematic for a VT VR-140 Guitar
Equalizer amp from he 70's I've tried just about everywhere and I'm now
seeking information here. I'd really like to get it back up and see
what it sounds like so if anyone here has a schematic please let me
know.
Click to expand...
Google is your friend.

http://www.musicparts.com/products.asp?Company=Vibration%20Technology

Twenty bucks.
 
"Videlectrix" <bcgobraves@gmail.com> wrote in message
news:1165437554.717121.122040@j44g2000cwa.googlegroups.com...
I have a problem with the 3-cd changer component of an Aiwa all-in-one
system. The problem is that the player keeps leaving a mysterious
residue on CDs, always at the same distance from the center and no
matter which position (1/2/3) the disc is in the tray.. The residue
comes off OK but seems to be slightly abrasive as sometimes removing it
leaves small scratches on the CDs. I have tried cleaning the lens and
the tray; if this has any effect it is only temporary as this problem
has been going on for some time now. Any insights would be appreciated!
Click to expand...
Which side of the disc are we talking here ??

Arfa
 
The SD TV is essentially analog HDTV. Unless you have cable or satellite
service it will be useless after the broadcasters switch off analog in a
couple years.

jerry_maple@hotmail.com wrote:

Elle wrote:



Yesterday at Best Buy a clerk there said buying any of the
flat screen TVs meant I would have HDTV. Without cable or
satellite with HD, the display would have black vertical
bars covering something like three inches on both sides. If
I wanted to continue using an ordinary antenna, I'd have to
go to a conventional TV with a 4:3 aspect ratio.

Can someone please confirm or deny what the clerk said and
maybe elaborate? Meanwhile I am googling on the subject.




I think it depends on the screen size. I was in Best Buy last night. In
the 19-20" screen size, you can still find an LCD SDTV in the 4:3
aspect ratio. They had one on sale for something like $220. We're
looking for something to put on the wall of a very small bedroom in our
cabin - complicating factor is that we want it with built-in DVD
player, those things are still kind of rare and expensive.

Jerry
Click to expand...
--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"Š

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P
 
Mark D. Zacharias wrote:
If the fuses are really good, this is a bad sign, given what you have said
about using the 12 to 120 converter. Possibly a bad power transformer.
With the receiver unplugged, use your DMM to measure resistance (ohms) at
the AC switched outlet on the rear panel. This outlet directly parallels the
main transformer primary. If the transformer primary is OK, and there are no
blown fuses or other open circuit, then the resistance should be very low,
probably less than 1 ohm, since it is a large transformer. If it's in the
100 ohm range or greater, you are measuring only the primary of the standby
transformer, and the main transformer may be bad. Possibly a thermal fuse
opened inside the transformer.


Mark Z.
Click to expand...
Hi Mark - there is no switched outlet in the back of the stereo. It
has the main plug hard-wired in and various jacks for speakers and what
not, but no other place for any AC plug to go into. This is one of the
"mini-stereos" with the CD player, cassettes, etc, all in one self
contained unit.

I do currently have the main cover off and notice when you plug it in,
it makes the "normal" click after a couple of seconds (at least I think
that is normal), and one of the belt drives on a cassette motor jogs
forward for a split second. After that, the light to the main power
button LED is lit red, but the power to the system will not come on.
With that said, what else do you recommend? Thanks - John
 
replacing those caps fixed the problem.

but i got another problem. the riser/daughter board on the deflection board,
there is a white wire that is soldered as a jumper wire in the back of the
board, well the one end is soldered, and the other end came off somewhere,
and I have no idea where.


any ideas?


"Mike" <nospam@microsoft.net> wrote in message
news:REFdh.2111$SJ3.813@tornado.ohiordc.rr.com...
I got this set, it was totally dead, relay clicks. now its completely dead,
no relay click.


I tested the fuses, and tested the HOT, they test fine. Im going to run an
ESR check on the caps to see if i spot any bad ones.

The solder joints appear they have been redone in the past. so thats not
the issue.

any ideas?
Click to expand...
 
"Elle" <honda.lioness@nospam.earthlink.net> wrote in message
news:eaBdh.7036$sf5.5814@newsread4.news.pas.earthlink.net...
My ten-year-old television's display is mighty snowy much of
the time (when receiving local channels), until I give it a
good whack and I guess cause some connections to work
properly again. It's humongous and so hard to move by
myself. I am getting old and do not want to have to move it.
Rather than try to repair it, I am thinking of buying a new,
lighter, flat screen TV. I have been keeping an eye peeled
for specials at Circuit City, Best Buy, and Wal-Mart. I
looked at the latest Consumer Reports article on the
subject.

Yesterday at Best Buy a clerk there said buying any of the
flat screen TVs meant I would have HDTV. Without cable or
satellite with HD, the display would have black vertical
bars covering something like three inches on both sides. If
I wanted to continue using an ordinary antenna, I'd have to
go to a conventional TV with a 4:3 aspect ratio.

Can someone please confirm or deny what the clerk said and
maybe elaborate? Meanwhile I am googling on the subject.

I do not want cable or satellite or any extra costs. OTOH, I
also do not want a huge television to move around.

TIA

http://www.hdtvprimer.com/
Click to expand...
 
paragon66x wrote:
Mark D. Zacharias wrote:

If the fuses are really good, this is a bad sign, given what you
have said about using the 12 to 120 converter. Possibly a bad power
transformer.
With the receiver unplugged, use your DMM to measure resistance
(ohms) at the AC switched outlet on the rear panel. This outlet
directly parallels the main transformer primary. If the transformer
primary is OK, and there are no blown fuses or other open circuit,
then the resistance should be very low, probably less than 1 ohm,
since it is a large transformer. If it's in the 100 ohm range or
greater, you are measuring only the primary of the standby
transformer, and the main transformer may be bad. Possibly a thermal
fuse opened inside the transformer.


Mark Z.

Hi Mark - there is no switched outlet in the back of the stereo. It
has the main plug hard-wired in and various jacks for speakers and
what not, but no other place for any AC plug to go into. This is one
of the "mini-stereos" with the CD player, cassettes, etc, all in one
self contained unit.

I do currently have the main cover off and notice when you plug it in,
it makes the "normal" click after a couple of seconds (at least I
think that is normal), and one of the belt drives on a cassette motor
jogs forward for a split second. After that, the light to the main
power button LED is lit red, but the power to the system will not
come on. With that said, what else do you recommend? Thanks - John
Click to expand...
If it seems to turn on normally, with the speaker relay coming on after the
usual delay, and just no display, there is a chance that only the -30 volt
line for the display is down (or some other section of the power supply).
There is a 100 ohm fusible resistor on the power board, R901, near the large
connector which goes to the main board. This resistor could be bad.

There is also a separate fuse board, and there could be bad fuses there -
don't recall if you said you had checked those.


Mark Z.
 
James Jones <junebug@yahoo.com> wrote:

Anyone want to suggest where to start?
Try replacing C316 on the power supply....Hope this helps!
Click to expand...
You were absolutely right! I opened it up and C316 was
bulging, checked the ESR for kicks - 10x too high, replaced
it, checked the other caps (OK) and fired it up. Works
perfectly. That has got to be the fastest/easiest repair
I've ever done. Thanks!
 
Thanks for all the suggestions, Jerry, RFI Guy, Charles, B,
and T Shadow. I'll keep studying and exploring this.
 
The side that the laser reads

Arfa Daily wrote:
"Videlectrix" <bcgobraves@gmail.com> wrote in message
news:1165437554.717121.122040@j44g2000cwa.googlegroups.com...
I have a problem with the 3-cd changer component of an Aiwa all-in-one
system. The problem is that the player keeps leaving a mysterious
residue on CDs, always at the same distance from the center and no
matter which position (1/2/3) the disc is in the tray.. The residue
comes off OK but seems to be slightly abrasive as sometimes removing it
leaves small scratches on the CDs. I have tried cleaning the lens and
the tray; if this has any effect it is only temporary as this problem
has been going on for some time now. Any insights would be appreciated!




Which side of the disc are we talking here ??

Arfa
Click to expand...
 
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