Toshiba TV29C90 problem; Image fades to black...

[Mark D. Zacharias]

michael.w.appenzeller@lmco.com wrote:

I'm working on a Pioneer VSX-454 that has a shorted 2SA1302/2SC3281
output pair. I've been reading that there is a big problem with
counterfeits of these transistors. Does anyone who does a lot of
audio repairs have either 1: a reliable source for these transistors,
or 2: good substitute part numbers?

Pioneer has them, but they want $18 for the 2SA and $16 for the 2SC.
This would make the repair too expensive, since these (and the bias
transistor) blew while bench testing after fixing the original fault.

Mike
WB2ME

The new Toshiba replacements are 2SC5200 and 2SA1943.

The most reliable source I know of is B & D Enterprises. You can Google
Bdent.com for their phone number.

The newer Toshiba numbers are also being counterfeited. MCM sells
replacements for the 1302 and 3281, same as Pioneers', made by Onsemi using
Motorola jigs, which Motorola had previously got from Toshiba, so the story
goes.

Mark Z.

 

[kip]

Change the needle valve..
Get a Carb KIT.


yikes

"spongehead" <hgoodale_msp@msn.com> wrote in message
news:1115898463.816012.27360@g49g2000cwa.googlegroups.com...

Thanks for all the replies, I will be taking the carb off for a good
cleaning and replace the air filter. I'll let you know how it goes.
Thanks again!!

 

[Sam Goldwasser]

"kip" <nospam@nospam.com> writes:

Change the needle valve..
Get a Carb KIT.

Unless he tightened the needle valve with a pair of Vice-Grips, needle
valves don't go bad, but may get dirty.

Clean the carb first.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
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[kip]

Yes But its just easier to put a New one in
cause the chances of him ruining the valve is pretty good.
We are not talking big coin here ..
Just done my Lawnboy ..
cheers
kip
"Sam Goldwasser" <sam@saul.cis.upenn.edu> wrote in message
news:6wekcc8vtv.fsf@saul.cis.upenn.edu...

"kip" <nospam@nospam.com> writes:

Change the needle valve..
Get a Carb KIT.

Unless he tightened the needle valve with a pair of Vice-Grips, needle
valves don't go bad, but may get dirty.

Clean the carb first.

--- 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:
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is
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[Asimov]

"cnctut" bravely wrote to "All" (11 May 05 10:52:14)
--- on the heady topic of "Re: Lawnmower idle question"

From the small motor faq:

" Air vane governor. The air flow provided by the
flywheel/blower passes by a plate which is coupled to the
carburetor throttle plate acting against a spring force.

Flyweight governor. A spinning gear assembly with a pair of
weights is driven by the camshaft. As the centrifugal force
of the weights increases, they move a sleeve which presses
against a lever whose shaft passes through the crankcase.
This lever then operates the carburetor throttle plate
against a spring force.
With both types, increasing the spring force will increase the
engine speed.
"

Hunting is often caused by a defect in the governor system. Check the
blade (plastic?) of the governor paddle is free to move and that the
cam to which it connects has the proper spring tension. As the motor
speeds up the flywheel impellor blows air against the blade and cuts
the trottle down. When the motor slows down the blade drops back and
the spring returns the throttle higher.

Often grass goop gets into the governor paddle axle and may stick or
seize. You might need to remove the pull cord/motor cover and perhaps
the carb/fuel-tank to get at it. Thankfully you won't need a puller to
get the flywheel off. If you ever do, inspect the key pin in the
shaft, as it must be snug, not worn. This could also cause hunting.

OTOH, if instead of the fan your motor has a governor linkage coming
out the bottom of the motor, then the linkage may have slipped.
Hunting means in this case it may be opening the throttle too much.
There is also a spring arrangement in this type to the trottle cam.

A*s*i*m*o*v


cn> From: "cnctut" <cnctutwiler@wmconnect.com>
cn> Xref: aeinews sci.electronics.repair:47853

cn> spongehead wrote:

I have an old Briggs and Stratton 3.5hp push behind lawnmower and the
idle revvs up and down constantly. Never idles normal. The spring
on
the shaft idle looks good. Any help on what this might be would be
greatly appreciated.

cn> Spongehead--

cn> Recommend cleaning the air intake sponge first then let us know if the
cn> problem still exists. I assume you have the 99 dollar Walmart mower
cn> with no variable throttle.

cn> Tut


.... The first rule of intelligent tinkering is to save all the parts.

 

[Asimov]

"EL" bravely wrote to "All" (11 May 05 13:52:03)
--- on the heady topic of "Re: Lawnmower idle question"

Eric,

Don't quit your day job to become a stand up comedian.

A*s*i*m*o*v


EL> From: "EL" <nospam@here.com>
EL> www.newshosting.com Xref: aeinews sci.electronics.repair:47856

EL> First you want to make sure all the phase alignment coils are peaked
EL> and the transratiometric detector is properly balanced. Then inject a
EL> circular wave about 1A P-P into TP31C and listen for feedback around
EL> the modulator. If any is found, replace F4.

.... Don't mess with a man that has a rubber chicken.....

 

[Jim Yanik]

"cnctut" <cnctutwiler@wmconnect.com> wrote in
news:1115859563.827681.275170@g44g2000cwa.googlegroups.com:

Jim Yanik wrote:
"cnctut" <cnctutwiler@wmconnect.com> wrote in
news:1115834384.004575.180400@o13g2000cwo.googlegroups.com:

Any reliability issues concerning a new Sharp R-1540 microwave to
power
it off a square wave inverter when camping? Is there any real
difference between "square wave" and "modified square wave"
inverters?

Thanks

Tut


Iron-core transformers do not like square waves-the harmonics just
generate
excess heat in the core.You would need a hefty inverter to power the
average MW oven;they run about a kilowatt output(~15A@120VAC
input),and
with an iron-core transformer,the startup surge would require more
inverter
power.

I'm ok with a little bigger inverter if you think the extra heat for
the microwave transformer won't be a problem over one 2 or 3 minute
duty cycle.



"modified squarewave" inverters generate a stepped version of a sine
wave,reducing the harmonic output.

Are you saying a modified square wave inverter has multiple stair steps
to max voltage vice one large step for older pure square wave
inverters?

Yes,AFAIK.




--
Jim Yanik
jyanik
at
kua.net

 

[Sheldon Cribb]

The PDF is located here (but I think it has erros in it):
http://www.eserviceinfo.com/index.php?what=search2&searchstring=HP8116A

"E51-E62 Error indication for dedicated services tests"


<francesco.messineo@gmail.com> wrote in message
news:1115900790.270220.260380@z14g2000cwz.googlegroups.com...

Hello,

does anyone have an electronic version of the hp-8116A service manual
and/or
can tell me what the E51 error means?

Thanks in advance and best regards

 

[Sam Goldwasser]

"Asimov" <Asimov@-removethis-bbs.juxtaposition.dynip.com> writes:

"cnctut" bravely wrote to "All" (11 May 05 10:52:14)
--- on the heady topic of "Re: Lawnmower idle question"

From the small motor faq:

" Air vane governor. The air flow provided by the
flywheel/blower passes by a plate which is coupled to the
carburetor throttle plate acting against a spring force.

Flyweight governor. A spinning gear assembly with a pair of
weights is driven by the camshaft. As the centrifugal force
of the weights increases, they move a sleeve which presses
against a lever whose shaft passes through the crankcase.
This lever then operates the carburetor throttle plate
against a spring force.
With both types, increasing the spring force will increase the
engine speed.
"

Hunting is often caused by a defect in the governor system. Check the
blade (plastic?) of the governor paddle is free to move and that the
cam to which it connects has the proper spring tension. As the motor
speeds up the flywheel impellor blows air against the blade and cuts
the trottle down. When the motor slows down the blade drops back and
the spring returns the throttle higher.

One note though: He has an idle speed problem where the governor is
likely not involved unless it is way misadjuated.

--- 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.

 

[Travis Jordan]

alexwright321@altavista.com wrote:

Anyone know how-to make a cable that would plug into my telephone jack
and then into my computer soundcard?

I bought one from EBay and when I plug the cable into my phone line
and then into the soundcard my line
goes dead.

The one you bought probably works fine with an ac-isolated microcassette
recorder with a high impedance microphone input.

One guy mentioned he uses an isolator circuit of some sort to not
short out the line in his device.

Yep, that would be a good idea.

Personally, I'd build such a device with a couple of .1 mfd coupling
capacitors and a 600 ohm to 600 ohm isolation transformer to provide a
balanced input. Total parts cost about $5.00. However, if you need to
buy one then....

http://www.omnicronelectronics.com/analog/LIC-100.htm

 

[TAYALS]

Hello Gerd,

1) I have schematics about Philips PM3617 (like PM3267 but with
BW=50MHz only). Do you want this documentation?

2) I'm looking for schematics, service manual,... about Logic Analyzer
PM3632.
Could you help me?

Regards,
Patrick
-----------------------------------------------------------------
Gerd Prien Wrote:

Hi,

anyone here who has a service manual or schematics for the Philips
oscilloscope PM3267? I'm also looking for PM3311.
I can deliver schematics for oscilloscope PM3218 and for the logic
analyser PM3632.

Thanks, greetings
Gerd

--
TAYALS

 

[Sam Goldwasser]

"cnctut" <cnctutwiler@wmconnect.com> writes:

spongehead--

A carb swap may solve your problem if off a similair 3.5 engine--too
much work though. You mentioned your throttle adjustment was
frozen--you might try advancing the control wire (pliers might help)
toward a faster run postion to get away from slow idle.

If this doesn't work--carb cleaner would be my next attempt at solving
the problem. Squirt it every where (in and around the carb.)

Lastly, as your time and parts cost creep higher and higher--don't
forget a new 3.5HP mower is only $99. ;-))

What fun is that? ;-)

--- 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.

 

[DaveM]

The unit at http://www.omnicronelectronics.com/PC/LIC-1PC.htm is more
appropriate for the OP, according to his stated problem. However, if the OP
has the ability, there is a schematic of such a unit at
http://www.solorb.com/elect/phone/tap. Another one with some good details
at http://www.epanorama.net/documents/telecom/telerecord.html.
The problem with the cable he bought on Ebay is that since there is no
isolation, one side of the phone line is directly grounded to the computer
case, which will indeed kill the phone line. The phone line must stay
balanced and isolated from ground at all times, otherwise, the telco gets
mighty upset. In fact, if you leave the line in a shorted condition, they
will send a guy out to test your circuit, and if he finds the short exists
inside your house, most likely the service will be disconnected until you
remove the short. And they will charge you for the service incident.

--
Dave M
MasonDG44 at comcast dot net (Just subsitute the appropriate characters in
the address)

Never take a laxative and a sleeping pill at the same time!!


"Travis Jordan" <no.one@no.net> wrote in message
news:aNPge.20529$7i2.835@fe03.news.easynews.com...

alexwright321@altavista.com wrote:
Anyone know how-to make a cable that would plug into my telephone jack
and then into my computer soundcard?

I bought one from EBay and when I plug the cable into my phone line
and then into the soundcard my line
goes dead.

The one you bought probably works fine with an ac-isolated microcassette
recorder with a high impedance microphone input.

One guy mentioned he uses an isolator circuit of some sort to not
short out the line in his device.

Yep, that would be a good idea.

Personally, I'd build such a device with a couple of .1 mfd coupling
capacitors and a 600 ohm to 600 ohm isolation transformer to provide a
balanced input. Total parts cost about $5.00. However, if you need to
buy one then....

http://www.omnicronelectronics.com/analog/LIC-100.htm

 

[Franc Zabkar]

On 12 May 2005 07:27:12 -0700, "gstringe" <egnirts@comcast.net> put
finger to keyboard and composed:

gstringe wrote:
Viewsonic P220f still on it but flying in the dark with no
schematic.QH07 and QH08 are a complementary pair in the horiz ckt and
attached to each other but since removing them and marking them I am
having second thoughts of whether I put them back correctly. Anyone
have a schematic that they could look at for me. They are BD140 and
BD139 transistors.
Many thanks

Thanks Frank, So far what I see on the pc board is that the parts have
a letter designating the circuit they are part of, hence the H for
horiz. This goes for all the parts, caps, resistors, coils etc.

Could the transistors be from some kind of horizontal centring
circuit?

I really haven't traced the circuit to look for the power connection
as I figured someone with a schematic would be easier but I guess I am
getting lazy in old age ;-)

Can you power up the monitor in the absence of the transistors? If so,
then measure the voltages at the pins. That should tell you which way
the current flows.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[none]

On 11 May 2005 10:40:01 -0700, "spongehead" <hgoodale_msp@msn.com>
wrote:

I have an old Briggs and Stratton 3.5hp push behind lawnmower and the
idle revvs up and down constantly. Never idles normal. The spring on
the shaft idle looks good. Any help on what this might be would be
greatly appreciated.

It's the carbuerator diaphram, worn out most likely.
Yours is the plastic bodied carburator with the black or red primer
bulb yes?
If so you'll need to purchase a new diaphram and gasket for the carb,
about 4 bucks or so at a lawnmower parts shop.
The carb is secured with 5 philllips head screws. Take those out and
gently pry the plastic carb off the fuel tank.
Take care not to lose the diaphram spring( it'll be on the bottom side
of the carb.) or the mesh filter screen on the main fuel intake port.
Note whether the fiber gasket is on the carb side or the tank side(
varies with each model.) of the rubber diaphram.
Replace new ones in that order. Take care not to crease or wrinkle the
rubber diaphram whille tightening the screws down and you should be
good as new.
While apart use a good aerosol carb spray to clean out the carb and
tank resevoirs.(just about any brand but Gumout will do, I use Super
Tech brand found at Wal-mart. Autozone brand of carb spray is good as
well.)
Spray through the intake port(under mesh screen) to back flush the
supply pipe and the main port in the carb throat as well.
blow off any excess cleaner or allow to dry before replacing rubber
diaphram.(cleaner will attack the rubber shortening it's life.)
Any questions in particular just post back.
One of my many skills is small engine mechanic and I have years of
experience with lawnmowers.

 

[quietguy]

But dont forget to check and clean/replace the fuel filter while you are
doing the job

David

spongehead wrote:

Thanks for all the replies, I will be taking the carb off for a good
cleaning and replace the air filter. I'll let you know how it goes.
Thanks again!!

 

[H. Dziardziel]

On 10 May 2005 08:36:11 -0700, electricitym@yahoo.com wrote:

Why just 3 books?... go to your local public library and look over a
wide selection of books on the subject. "Electronics" is such a broad
subject that there will be numerous subcatagories to chose from. Find
books that fit your area of interest and check them out.... there will
be many more than three books. As your experience and knowledge level
increases you will then be checking out more in-depth and specific
books.
electricitym
-
-

Not every country has good or many public libraries and any books
there are, of course, in local languages. However much of the
technical material that universities in these countries use, are
in fact, invariably English lanuage textbooks. So, students do
research in book stores, some of which are quite understanding
about that. A few good recommendations are thus useful since
international textbook purchase is generally free of restriction.

-

Nikolas Britton wrote:
Hypothetically, If you where only allowed to read and have 3 books
about electronics what would they be? This is pretty broad, so let's
try and keep the focus on intermediate level, or above, books with an
emphasis on analog electronics. Books on troubleshooting would be
nice
too.

Thank You.

 

[Sam Goldwasser]

"cnctut" <cnctutwiler@wmconnect.com> writes:

Sam Goldwasser wrote:
"cnctut" <cnctutwiler@wmconnect.com> writes:

spongehead--

A carb swap may solve your problem if off a similair 3.5
engine--too
much work though. You mentioned your throttle adjustment was
frozen--you might try advancing the control wire (pliers might
help)
toward a faster run postion to get away from slow idle.

If this doesn't work--carb cleaner would be my next attempt at
solving
the problem. Squirt it every where (in and around the carb.)

Lastly, as your time and parts cost creep higher and higher--don't
forget a new 3.5HP mower is only $99. ;-))

What fun is that? ;-)

--- sam | Sci.Electronics.Repair FAQ Mirror:

There are practical limits to fun--the grass keeps growing and the wife
doesn't like it long. Remember that microwave I was trying to
fix--"Sharp powers down after 40 seconds"--couldn't get parts so bought
a new one. The wife is very happy now--should have bought a new one
earlier--good note is that my parts box is now full of used microwave
items--maybe I can use some of them before I die--probably not
though.;-))

Oh, I definitely agree when it comes to strange problems like the one
you had. But unstable idle on a lawnmower engine isn't rocket science
or something that's likely to stump everyone.

And there's my "fix once rule": I don't mind repairing something I picked
up on eBay cheap (replaces garage sales!) or what I might have bought new
many years ago. But I don't want to have to deal with it more than once!

--- 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.

 

[Travis Jordan]

DaveM wrote:

The unit at http://www.omnicronelectronics.com/PC/LIC-1PC.htm is more
appropriate for the OP, according to his stated problem. However, if
the OP has the ability, there is a schematic of such a unit at
http://www.solorb.com/elect/phone/tap. Another one with some good
details at http://www.epanorama.net/documents/telecom/telerecord.html.
/analog/LIC-100.htm

The zener diodes across the transformer secondary are a good idea.

 

[Travis Jordan]

Jeroen wrote:

FW0128 is probably some production date code. The 'W' seems to be the
Motorola logo. So the full part number is FQP50N06.

$1.36 at Mouser.