Toshiba TV29C90 problem; Image fades to black...

[Dave D]

"Leo Tick" <tick@cs.nyu.edu> wrote in message
news:eno1b.42$R5.3463@typhoon.nyu.edu...

Jim Adney wrote:
On Thu, 21 Aug 2003 09:45:28 -0400 Leo Tick <tick@cs.nyu.edu> wrote:


On a cpu fan with three wires what is the protocol and
the signal in the sence wire. The question is asked
obviously because the fan does not spin but the fan part is ok
applying 12 v directly does get it to spin. Does the sence
line tell the mobo to turn on the 12v or what . If this is
the case what do I send down the sencs line to see if the
failure is in the MOBO.


The 3rd wire is nothing more than an OUTPUT from the fan to the MoBo.
If the fan is not turning then either there is a problem with the fan
or with the 12V supply on the MoBo. You should be able to measure the
supply voltage, with the fan connected, or connect the fan to a known
good power source. Either way should tell you where the fault lies.

Or just try a different (known good) fan on this connector.

-
I am afraid you missed part of my comment. The fan is known to be
good. It is in use with the 12v line connected to a 12 vold source.
I am tring to determine if the failure is in the MOBO which is not
supplying 12v from the three pin connector OR was some logig
involving the sense line at fault. Consenses here seems to be a circuit
failure.
Thanks

I've seen this fault before. If there is a fault on the motherboard which
grounds the tacho wire from the fan, some fans cannot start up. The simple
solution is to remove the tacho wire from the connector leaving the 12V and
0V wires, and the fan should run.

Why does shorting the tacho wire stop the fan starting? Well, the same part
of the fan circuit which supplies the tacho pulses to the tacho wire is also
used to switch the coils in the fan motor. Shorting out these pulses stops
the fan spinning.

Dave

 

[Dave D]

"raimondo" <cerai@libero.it> wrote in message
news:3c5cd234.0308240228.7515117f@posting.google.com...

Please can someone tell me where it's possible to find the circuit
diagram for sony CPD-1704S monitor. I haven't any other information
thank you
Cerrato Raimondo

Have a look here, they might have that chassis.

http://rv6llh.rsuh.ru/shema.htm

Dave

 

[tim kettring]

True , I would use the shacks " silver-solder " .

The other thing to remember , is that a light-bulbs filament
resistance increases with age .

You might find a non-automotive use for the old bulbs , like 12v
lighting when the 110 power fails .

The ground connections may also be corroded as they always get in
almost all vehicles in a few years .

tim , CET , ASE , ETC...

"Digi Man" <xenos_k@hotmail.nospam> wrote in message news:<3f48c873$1@news.sch.gr>...

Contacts are oxydiesed and current flowing thru them is decreased. This
triggers the safety warning light.
The soldering on the after market bulbs is very bad. Redo solderings ON
BULBS only with better one (prefer 2% cu included).

"Wdyorchid" <wdyorchid@aol.com> wrote in message
news:20030824075921.11748.00000461@mb-m11.aol.com...
My Honda seems to tell me that my bulbs are burnt out by constantly show a
warning light on the instrument gauges. Here's how the system works:
when the
brakes are applied the control unit detect bulb action and doesn't show a
warning light on the instrument gauges. If a bulb isn't detected then it
display a warning light.

The problem is that even though bulbs are okay, replacing with fresh bulbs
are
the only way to make the warning light go away. What is causing the
circuit to
trip? Here take a look at what I'm taking about in color diagram.
http://autotails.tripod.com/brakes.htm

 

[tim kettring]

Replace c113 for starts , that value fails constantly in sterios !!!

It is probably leaky , and not even worth testing in a live leackage
meter , With all the " c113 "s , i have replaced and fixed amps etc...
with , I would just replace it ( preferably with the same voltage
rating ).

That value is extreamly common on scrap parts boards , TVs , Sterios ,
etc...

tim cet

 

[tim kettring]

The other thing to consider on c113 , is that it is just not worth a
future recall of trashed outputs just because of a leaky cheap cap
starting to go bad and railing the outputs ( crispy-criters ) !!!

tim

wdyorchid@aol.com (Wdyorchid) wrote in message news:<20030824071706.11748.00000460@mb-m11.aol.com>...

I've completed tests on all resistors as suggested. I'd clip them and tested
them. Everything within the green line you saw in the schematic is now either
fully checked or replaced including R113 and C113. C113 doesn't seem short
since it measures about 4 Ohm across it and wasn't replaced. The only yet to
replace is Q105. This one (still in the circuit board) is hard to get and
checks out fine with a diode tester. I will replace it tomorrow. Only Q107 is
not an exact replacement part. Let's say I'd replace Q105 and still won't
work, should I look into the negative side for the problem. The (-) power
supply seems normal.

Both the left and right channels have the same offset. Even though replaced
most of the parts (5 out of 6 transistors) the readings still is as bad as
before.

Please let me tell you gentlemen how happy I am to receive so much amazing
help.
-Wd

***************************
I'd bet on Q107 and its surrounding parts, since they're responsible for
bias. Also check FR101 and all those low voltage resistors.
Ricardo
***************************
Are you saying on your webpage that both the left and right channels
have the same offset? If so I would look at the -44 v source for the
problem. If not Q105, Q107, and R113 would be prime suspects. Also,
if you didn't use exact replacement parts, I would check the lead
orientation very carefully. This amp is designed to shutdown entirely
if there is any amp problems. It should shut down in 2 to 3 seconds.
Chuck
****************************
Just a quick look at the schematic.. I'd look at C113 the bootstrap,
possibly it has a partial short bleeding the b+ into the output.
Lubbie
*****************************
For what it's worth, here's what I think. You stopped short of a good
diagnosis (maybe you should have stayed in school for a few more weeks,
huh?). Since you say that all the resistors in the area are good,
concentrate on the semiconductors for a minute and let's analyze your
(incomplete) measurements.
There is 28V on the bases of Q128 and Q129, and also on the emitters of Q109
and Q111, which under normal conditions are fairly well balanced. That
means the there is a serious imbalance in the circuit somewhere. If by
removing the positive power source (by removing R125), you restored the
balance, that means that the imbalance must be due to bad component(s) in
the negative side.
Sticking my neck out, I'd bet that if you replaced Q105, you'd probably be
back in operation. It would appear that that transistor is Open C-E. That
would go far in explaining why the voltages around the circuit dropped back
to (near) normal when R125 is removed. Since the negative supply path is
open, then opening the positive supply should restore the balance. Ergo...
voltages seem normal, but they're really not, since the power sources have
been effectively removed.
Let us know how it turns out.
Cheers!!!!!-- TweetldeeTweetldee at att dot net (Just subsitute the
appropriate characters in the address)Time is what keeps everything from
happening all at once.
*********************
http://autotails.tripod.com/zoom.htm

 

[tim kettring]

The best ( cheap ) way to check junction transistors for shorts and/or
excessive leakage is to make a curve tracer using an old " lab " scope
, and about a 3-6 volt transformer , email me , and I will try to
hunt-up or simulate details ( scope must have a horizontal-drive input
)

total cost , besides scope , the price of salvage transformer and
switch and resistor ( s ) 3 if you want a good one , but 1 resistor
will do .

tim

wdyorchid@aol.com (Wdyorchid) wrote in message news:<20030822041804.10910.00000511@mb-m14.aol.com>...

Take a look at this schematic. The green line is faulty line measuring 28V
which should be 1V. Assuming that replacing four transistors in these general
areas would solve it, but it didn't. What can I be missing?

Details: Q111, Q109, Q129C, and Q129A replace same time. Measurements were
taken and still the same as before. (Thinking Q111, Q109 drives the output
transistors (Q129A, Q129C, replacing them would solve something) All the
transistors were checked with a diode tester but didn't paid attention to
comparing them before installing them. What is the correct way to test them
with a diode checker? (I'd been using a logic pulser before but lost it.)
Receiver is a Dolby pro logic RX-V480.

http://autotails.tripod.com/zoom.htm

 

[tim kettring]

YES , but unless it is either something very simple to fix , or is
AT-LEAST a 19" , they will probably not want to waste much time on it
!!!

tim , been there, fixed that .

"Dan" <cauley@nospam.telus.net> wrote in message news:<3GW1b.39711$K44.20111@edtnps84>...

I advise you take you T.V. to a repair shop where they can perform a proper
diagnosis, and in many shops, offer a free estimate.

Dan
"DukeN" <vince15@removediscogeco.ca> wrote in message
news:3F46CE0A.640931FE@removediscogeco.ca...
Hello.

I have an RCA f27665 (I believe thats the correct model number). The
picture is'nt appearing on it tho. The sound works fine, and I can see
the channel numbers and time and menus and such.

However the actual inputs dont work - cable, DVD, S-video,
componenent..nothing (same symptons - sound but no video).

Any ideas?

Thanks.

 

[Jason D.]

On Sun, 24 Aug 2003 17:38:17 GMT, "G. Skiffington"
<skiffing@nbnet.nb.ca> wrote:

Hello all.....This color VGA monitor has been blurry for a the couple of
years I've owned it (used), and I've only made a slight improvement by
slight adjustment of the HV control and external brightness and contrast
pots. There is lots of brightness and good control of both it and the
range of contrast. Searching the web found slight reference to a
possible defect from new (other vague reference is to maybe it being a
bleeder resistor). Does anyone here know if there's a common problem to
this monitor with respect to this problem? Any specific info
appreciated - Thanks.

IBM TYPE is 8513-001
Monitor p/n 59X6293
FRU p/n (?) 68x3088

Gord

Wow!! 8513 still alive? Replace flyback transformer, focus section
in that flyback transformer fails frequently, I did two before, IBM
had recall on those but that recall period was long time since over.
Cost? not that expensive actually for that fly from decent electronics
suppliers, so many out there back then. Remember to discharge HV on
that tube to dag ground strap before replacing that flyback.

Cons:
Only 12" CRT, the true viewable size is much smaller (like 10" because
this doesn't "scan to the edges", extremely tiny, can only 640x480 at
one freq 60Hz, compareable decent monitor was 14" or larger in that
era couple years after this 8513 and had 800x600 72Hz. The main
problem is the components is very old and really aged from all that
heat & stress, replacing flyback is not only one to fix, you have to
account for the CRT aging, electronics aging etc. User control is
only contrast & brightness, that it. Decent monitors has more
controls for user to adjust externally.

PS: better to ditch if you can do that. This that little beauty is
from 1988-1990 (introduced around 1987 to go with IBM PS/2 series)
era. Low end like Samsung 17" S or V series is plenty enough and can
be had for 100 or so. 1024 x 768 75 or 85Hz on very sharp tube and
still can sync to any lesser resolutions including 8513 specs. Even
cheaper to get 15" samsung monitor if you can get your hands on one.
If you are willing to spluge bit more, Samsung 753MB, very nice
monitor flat CRT .20mm dot pitch, all Samsung monitors has 3 yr
warrenty.

Cheers,

Wizard

 

C113 doesn't seem short
since it measures about 4 Ohm across it and wasn't replaced.

An ohmeter is the wrong tool to use on a cap, other than looking for
low resistance. You should have a very high resistance on a cap,
which leads me to believe this cap is questionable.

-Chris

 

On 24 Aug 2003 12:18:15 GMT, wdyorchid@aol.com (Wdyorchid) wrote:

I bought a smoothie maker and blend some juicy strawberries ice cream for the
kids. But how come the fuse burns out on me? Jolene uses it, and everyone do.
But when it's my turn it blows out the fuse. We like this model a lot so we
bought another one and I burnt out the fuse again.

So I take it apart and replaced the fuses, at first the fuses were impossible
to find, only to be found hidden into the wires it seems. And it looks like a
diode. What is causing the smoothie to burn out? Did I blend too long, too
heavy a load or bad fuse rating? Should I increase the fuse rating - *sorry
already did.*
-w

Please describe the "fuse". Is it a current fuse or thermal fuse?

 

[raimondo]

"Dave D" <someone@somewhere.com> wrote in message news:<biabtg$snf$1@titan.btinternet.com>...

"raimondo" <cerai@libero.it> wrote in message
news:3c5cd234.0308240228.7515117f@posting.google.com...
Please can someone tell me where it's possible to find the circuit
diagram for sony CPD-1704S monitor. I haven't any other information
thank you
Cerrato Raimondo

Have a look here, they might have that chassis.

http://rv6llh.rsuh.ru/shema.htm

Dave

I've already visited that site, unfortunaly there isn't the model
I need. Thanks a lot for your answer...
Raimondo

 

[kc8adu]

what board is it from?
i have a bunch of new/remaned zenith stuff.
"Robert McPherson" <rm502@bellsouth.net> wrote in message
news:1fe013f5.0308210914.5bfe420a@posting.google.com...

Original # 95-4170. Anyone have a new or good used transformer for
sale or know of a source for one? Thanks!

 

[Volk]

On Sun, 24 Aug 2003 19:10:50 GMT, Jason D. wrote:

On Sun, 24 Aug 2003 17:38:17 GMT, "G. Skiffington"
skiffing@nbnet.nb.ca> wrote:

Hello all.....This color VGA monitor has been blurry for a the couple of
years I've owned it (used), and I've only made a slight improvement by
slight adjustment of the HV control and external brightness and contrast
pots. There is lots of brightness and good control of both it and the
range of contrast. Searching the web found slight reference to a
possible defect from new (other vague reference is to maybe it being a
bleeder resistor). Does anyone here know if there's a common problem to
this monitor with respect to this problem? Any specific info
appreciated - Thanks.

IBM TYPE is 8513-001
Monitor p/n 59X6293
FRU p/n (?) 68x3088

Gord

Wow!! 8513 still alive?

I have a 8511 you can have FREE... you pay shipping.
It still works fine... I got it new.

 

[Dmitry Razumov]

Try here www.electronicsrepair.net

"raimondo" <cerai@libero.it> ???????/???????? ? ???????? ?????????:
news:3c5cd234.0308240228.7515117f@posting.google.com...

Please can someone tell me where it's possible to find the circuit
diagram for sony CPD-1704S monitor. I haven't any other information
thank you
Cerrato Raimondo

 

[Ralph Wade Phillips]

Howdy!

<not@not.not> wrote in message
news:n0vikv89e36eirahlhn6th61tiahmf0vo4@4ax.com...

I have has it with these VCR's that turn the screen blue when the
signal gets weak. I live in a rural area and am used to weak
reception, since the nearest station is 60 miles away. Having a signal
get fuzzy and losing a few words of the sound is not that big of a
deal, but when I am watching something, or worse yet, taped something
and that god damn blue screen keeps popping on and off is more than I
can take. The first VCR that did that I threw in the trash. I
thought it was just a bad VCR. So I buy another one and it did the
same god damn thing. That one got me so angry I threw the fucking
thing thru the livingroom window, which cost me almost $100 to repair
the window. I just bought an old one at an rummage sale, hoping it
would not have that fucking blue screen. Wrong, I just tossed that
one out the door, only 5 minutes after hooking it up for the first
time and it's in 10 or more pieces on the lawn. The asshole that put
that into the VCRs should be hung in times square by his fucking cock.
At least they could have put a disable switch somewhere on the thing.

Is there a way to disable it?

MY Hitachi VCRs have that as a setting in setup.

But why do you let the VCRs control you that way?

RwP

 

[Loren Coe]

In article <1098ee8a.0308210636.3e53a6e4@posting.google.com>, Dave Walker-Sharpe wrote:

Hi,

I have a Hitachi TV and sometimes, in certain weather it seems, the
picture will flicker around the edges briefly, then the screen will go
black, and the TV will drop out to standby. There is a kind of
electrical crackling noise from the back of the set whilst this is
going on. The TV always recovers, and comes back up as normal, but
may well die again 7 or 8 times before stabilising properly.

Does anyone have any ideas how I might fix this?

It was suggested to me that the HV supply transformer may be arcing,
and that a silicone spray was available to remedy the situation but I
^^^^^^^^^^^^^^

why, on Earth? --Loren

haven't been able to track down this product, or really get to grips
with the problem itself.

Many thanks,
Dave

 

[Wdyorchid]

Fuse type unknown. Listed on side probably says two amp, can't see. It's a
silver rocket shape size of a grain of rice that connects like a diode in
series on a wire and appears like a diode because of a marking, probably to
indicate direction. I'm sure it's a current fuse since thermal fuses comes back
to life I believe.
-w

Please describe the "fuse". Is it a current fuse or thermal fuse?

I bought a smoothie maker and blend some juicy strawberries ice cream for
the
kids. But how come the fuse burns out on me? Jolene uses it, and everyone
do.
But when it's my turn it blows out the fuse. We like this model a lot so we
bought another one and I burnt out the fuse again.

So I take it apart and replaced the fuses, at first the fuses were
impossible
to find, only to be found hidden into the wires it seems. And it looks like
a
diode. What is causing the smoothie to burn out? Did I blend too long, too
heavy a load or bad fuse rating? Should I increase the fuse rating - *sorry
already did.*
-w

 

[Sam Goldwasser]

wdyorchid@aol.com (Wdyorchid) writes:

Fuse type unknown. Listed on side probably says two amp, can't see. It's a
silver rocket shape size of a grain of rice that connects like a diode in
series on a wire and appears like a diode because of a marking, probably to
indicate direction. I'm sure it's a current fuse since thermal fuses comes back
to life I believe.

It's a thermal fuse and you're overheating the things.

That type doesn't come back to life.

--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: The email address in this message header may no longer work. To
contact me, please use the Feedback Form at repairfaq.org. Thanks.

 

[Marco De Vitis]

Il 19/08/2003, alle ore 15:50, Marco De Vitis ha scritto:

Today I tried swapping the capacitors back to their original
positions, but the situation is exactly the same: the color is ok, but
the line is still there.

Just for the record, soon after writing my message the line
disappeared, everything seems ok now.
Who knows... I might guess it was some kind of leftover from the
previous situation (the two swapped capacitors), but it sounds to me
like nonsense.

--
Ciao,
Marco.

...."Dig?", Bill Bruford's Earthworks 1989

 

[Wayne Tiffany]

Sounds to me like the thermal overload device commonly found wrapped inside
the field windings of a motor. When these open, they don't reset. Anyway,
if that's what it is, it's thermal and caused by too much temperature, which
is caused by running the motor too hard, too long. The fact that others in
the household can run the machine without problems also suggests that
technique may be the issue.

WT

"Wdyorchid" <wdyorchid@aol.com> wrote in message
news:20030825091103.20921.00000730@mb-m13.aol.com...

Fuse type unknown. Listed on side probably says two amp, can't see. It's a
silver rocket shape size of a grain of rice that connects like a diode in
series on a wire and appears like a diode because of a marking, probably
to
indicate direction. I'm sure it's a current fuse since thermal fuses comes
back
to life I believe.
-w

Please describe the "fuse". Is it a current fuse or thermal fuse?


I bought a smoothie maker and blend some juicy strawberries ice cream
for
the
kids. But how come the fuse burns out on me? Jolene uses it, and
everyone
do.
But when it's my turn it blows out the fuse. We like this model a lot so
we
bought another one and I burnt out the fuse again.

So I take it apart and replaced the fuses, at first the fuses were
impossible
to find, only to be found hidden into the wires it seems. And it looks
like
a
diode. What is causing the smoothie to burn out? Did I blend too long,
too
heavy a load or bad fuse rating? Should I increase the fuse rating -
*sorry
already did.*
-w