Toshiba TV29C90 problem; Image fades to black...

[Hellraiser]

"Bluezman" <jfkl@ofjaw.net> wrote in message
news:cdnehvc9am0fa488am3ain0jlqdvqihasd@4ax.com...

I have a 1 year old Mag Innovisions 986FS (19" SVGA) monitor that is
displaying some very interesting problems.

At 60Hz refresh rate I can generate a viewable picture, but if I turn
it up to 72Hz or 75Hz, anything white will act like there is
over-voltage and ripple the screen. At 85Hz, the entire picture is
unviewable with this ripple.

Also, and this may not be related, the focus on this monitor is
attrocious. If the center is focused, the edges are blurred to the
point where 10pt text is too fuzzy to read, and the reverse is true if
the edges are in focus. I've set the focus to a medium range, but I'm
thinking it could be better.

Can someone offer some preliminary assessments of what to check for
first to try and alleviate the ripple and focus issues? Any help
would be greatly appreciated.

Firstly if it is 1 year old, it is still under warranty - get them to fix
it.

Second, if it's not, I have some bad news. The poor focus is usually due to
Mag using Samsung tubes, which are shit and tend to fail after 12-24 months
use. Don't even consider replacing them, just scrap the monitor and buy
something non-Samsung next time.

Hellraiser..........>

 

[li_gangyi]

I would take it...if not for the expensive shipping to Singapore...hai~~~



"Michael Black" <et472@FreeNet.Carleton.CA> wrote in message
news:bfcita$snj$1@freenet9.carleton.ca...

Ken Morrow (kenm@morro.co.uk) writes:

These items are available for collection in Stony Stratford, Milton
Keynes.

Email me if you are interested. Ommit the m after ken in the address
given
above.

Cheers,

Ken.

No Interest?

Is there a more appropriate group I could try, or are such items only
fit
for the dump?

Thanks,

Ken.

Have you tried posting in your local buy and sell newsgroup, or at least
one specific to the UK? You may find fewer people who are interested
in electronics, but you would at least find locals who obviously are
in the position to collect the items.

Plus, by posting where the general population might see it, you might
catch the attention of someone starting out or at least a relative
beginner, who has yet to catch on to the places where a more experienced
hobbyist might hang out.

I have no idea what your local buy and sell newsgroup might be, though.

Michael

 

[Shiva]

"Jimmy" <Gfender@carolina.rr.com> wrote in message
news:dweRa.241469$nr.9699112@twister.southeast.rr.com...

"Shiva" <helpdesk@666.com> wrote in message
news:1K2Qa.5127$Y92.1251@nwrdny01.gnilink.net...

"George R. Gonzalez" <grg2@comcast.net> wrote in message
news:hYTPa.43358$N7.5224@sccrnsc03...
I seem to have stirred up a lot of controversy here. Let me summarize
the
responses:


(A) You're right in adding the "missing" snubbers, missing fuses,
missing
bias controls, missing bias filters, missing bias test points, missing
bias
set points, especially since the amp
is acting up, even after replacing capacitors, looking it over...
etc.

(B) This Bogen amplifier is a part of our honorable tube heritage, the
ancient designers never made any design compromises, you should be
flogged
for even hinting of any possibility of cutting-corners by the
engineers,
or
suggesting
that the amplifier could be improved with a few modern components and
techniques.

(C) Bogen made high-quality stuff that lasted forever.

(D) Bogen made some stuff that was marginal, that blew tubes a lot.

---

In other words, all over the spectrum, and a lot more heat than
illumination.

I'll readily concede that all of the above may be true, although not
all
for
the same
amplifier model.

But as my viewpoint is mainly an engineering one, I see this more as
a challenge to tame, not as a historical artifact that should be
preserved
and worshiped as-is.

You all, are of course are entitiled to differ and to treat your
amplifiers
as you see fit.



Regards,


George



Occasionally one of these amps used to come into my shop with the output
tubes crispy fried. Usually this waas because the grid coupling caps were
shorted. replace these with 600 volt units. Also check other associated
componets for "doneness". Also be prepared to lay out much bucks for
replacement tubes. I wouldnt think an engineer would have much trouble
replacing these with something a little more economical, 6550's should be
a
good choice I think.

Have 4 used ones - came out of a working amp, look like crap, but all worked
& the amp pulled rated power. Offers?

 

[Jeff]

If you were refering to the pre/main out/in then please excuse, my mistake.
Jeff

"jakdedert" <jdedert@bellsouth.net> wrote in message
news:GLeSa.3258$wv6.26@fe03.atl2.webusenet.com...

Uh...just what are saying 'not really' to? I'm not following your logic,
although the advice in your next post is sound. I was referring to
monitoring the pre/main jumpers. The idea below of crossing those in/outs
is a much more simple, elegant way to do so, though.

jak

"Jeff" <frontline_electronics@NSatt.net> wrote in message
news:06%Ra.61661$0v4.4119515@bgtnsc04-news.ops.worldnet.att.net...
Not really, the tone section is after preamp but before
amp. It will be connected before pre/main in/out if the
unit has that.
Jeff

"jakdedert" <jdedert@bellsouth.net> wrote in message
news:grXRa.697$wv6.498@fe03.atl2.webusenet.com...
You need to be able to monitor the output of the pream somehow to see
if
it's noisey as well. However, since you stated that the headphone
output
was clean (right?), likely the problem is later in the signal chain.
If
not, one way to check that output is to record something from it on
tape
and
listen to the playback on known-good gear. Another way is to hook up
a
cheap set of computer speakers there. You will need the a RCA to mini
stereo plug adaptor to do so....

jak

"Sharon Leigh" <sleigh@aol.com> wrote in message
news:YzJRa.4665$KZ.1480428@news1.news.adelphia.net...
Jeff,

It's a model 2120. It does have a pre-amp output, but I didn't test
it.
I'm
not really sure what I need to do.

"Jeff" <frontline_electronics@NSatt.net> wrote in message
news:y9FRa.59888$3o3.3972922@bgtnsc05-news.ops.worldnet.att.net...
Ok, if it has preamp output is it OK?
DC voltage across output when noisy?
Model? (strange the headphone would be OK)
Unless its only distorted/noisy when loaded.
Jeff

"Sharon Leigh" <sleigh@aol.com> wrote in message
news:WboRa.3034$KZ.1115395@news1.news.adelphia.net...
Yes, I swapped speakers. I also moved the set over to the B
speaker
terminals. Guess what? Same problem.


"Jeff" <frontline_electronics@NSatt.net> wrote in message

news:31lRa.57999$0v4.3923232@bgtnsc04-news.ops.worldnet.att.net...
Have you swapped the speakers?
Jeff

"Sharon Leigh" <sleigh@aol.com> wrote in message
news:k4eRa.1876$KZ.911568@news1.news.adelphia.net...
Yes, I do have sound in the bad channel. I think the best
way
to
describe
it
is that it sounds like a radio station that's not tuned in
properly.
It's
staticy and garbled.
"bigmike" <bigmike@cornhusker.net> wrote in message
news:3f14de13$0$24599$9a6e19ea@news.newshosting.com...

"Sharon Leigh" <sleigh@aol.com> wrote in message
news:VA4Ra.1371$KZ.745283@news1.news.adelphia.net...
I was just reading the post about the marantz receiver
static
problem.
Mine's slightly different, in that it goes away when I
turn
the
balance
all
the way left, and my headphones work fine. I cleaned
every
conceivable
contact and circuit and still have the static. The
receiver's
32
years
old
so I am suspecting something has died or fried along the
way.
anyone
have
any ideas?


Lot's of possibilities. Dirty or worn speaker switch
contacts,
bad
relay
(if the old amp uses one) contacts, dried up caps, leaky
transistors.
Headphones require very little power to produce sound, so
some
problems
in
the output stage might not show up when using them. By
the
way,
do
you
have
sound through the bad channel along with the static, or
just
static?

 

[Don]

try rec.audio.tubes and rec.antiques.radio+phono, I'm sure you will get a
response.

In article <20f8de50.0307191258.54feec34@posting.google.com>, kenm@morro.co.uk
says...

kenm@morro.co.uk (Ken Morrow) wrote in message
news:<20f8de50.0307091344.5d4b415
d@posting.google.com>...
I am having a clear out.

Anyone want an old (vacuum tube) Roband RO50A oscilloscope
(30MHz bandwidth I think).
Complete with instructions and circuit diagrams.
Can't find the mains lead at the minute.
Worked OK last time I used it, which was about 10 years ago.


I also have 20 or so data books, mainly analogue, and mainly 1990s if
anyone wants them.

Also assorted other electronics bits (e.g. Old fax machine).

These items are available for collection in Stony Stratford, Milton Keynes.

Email me if you are interested. Ommit the m after ken in the address given
above.

Cheers,

Ken.

No Interest?

Is there a more appropriate group I could try, or are such items only fit
for the dump?

Thanks,

Ken.

 

[Netguy]

Hi, guys,

You can contact newg@softhome.net for any of your FBT & hard-to-find components.
Very affordable.

Thanks

Netguy
newg@softhome.net


u1061771156@csi.com (u1061771156) wrote in message news:<slrnbh0vnl.is.u1061771156@csi.com>...

In article <BB33DD72.96E5%kai.robinson@tiscali.fr>, Kai Robinson wrote:
Hey there! I did exactly as you said - and lo and behold - CLEAR PICTURE!!!
from a monitor from a Skip!! The quality is amazing - and it was such a
small adjustment - theres loads of range left in it as well - although i'll
order a spare flyback just in case - where did you get yours from? Cheers!!

Kai

I got it from PSA Parts ... June 2002:

"You can place a back order for 313812875530 on our web site. Price is
GBP60.00 + GBP6.80 carriage and the lead time is 7-10 days."

(Plus VAT of course).
Website is http://www.psaparts.co.uk/

At that price I'd _not_ recommend buying a spare while your existing one
is working OK. I'd be interested to hear if anyone knows of a cheaper
source ...

Mike.

 

[Netguy]

Hi,

I do agree with you guys, that we've been paying so much for a
flyback, and the've been ripping us so much! Because of that, I can
feel how frustrated we are that customer's walk away because it's
basiscally too expensive! How many customers you lost during the
years?

NOT ANYMORE, GUYS!
From today onwards, I'm here to help all the repair guys here.
You can now assure a afforable flyback for your repair.
In the end, I hope to se you happy, your's customer happy and lesser
monitors going to the dump. Which means good for enviornment.

So, just sent email to me at newg@softhome.net, and give me the detail
you need, like your TV or Monitor model, FBT no., and will get back to
yo u very soon.

Pls forward to those of your friends or anyone u think might be
helpful to him or her.

Thanks

Netguy
newg@softhome.net

"David" <dkuhajda@locl.net.spam> wrote in message news:<3eff2cca@news.greennet.net>...

Viewsonic 20" monitor. No matter where you go it is $85US give or take a
little. The demand is very high for that flyback. It is not your typical
el-cheapo tv flyback either. You either have to decide to buy one or throw
away the monitor.
David

Linux User <user@oem.com> wrote in message
news:l5tLa.315149$ro6.7708921@news2.calgary.shaw.ca...
Hi,
Does anyone know of good and afordable (below $50 US) supplier of this
flyback?
Thanks

 

[Jim Adney]

On Sat, 19 Jul 2003 00:09:00 GMT "William R. Walsh"
<newsgroups1@idontwantjunqueemail.walshcomptech.com> wrote:

I have one that tried rolling over all of its digits to reflect another
100K miles and it has been stuck with the numbers visibly "popping" and
clicking ever since....I guess something inside broke...

Sounds like a VDO odometer from an early 70s VW. If so, I can fix
these. Actually I can fix this common fault on any early 70s VW, but I
most commonly work on VWs.

-
-----------------------------------------------
Jim Adney jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

 

[Sofie]

its you / Steve:
Check the thrift stores or garage sales........ buy an old or "not so old"
stereo receiver...... and presto..... a transformer and other parts for
cheap.
If you shop around you can pay almost next to nothing and of course it
probably won't work, but you may be surprised and it just may work fine.....
if it does work fine you may not need to build an amplifier.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
-----------------------------------------


<its you> wrote in message
news:j6kkhv40l1gkmio6knr6s2kc64rdh7bbh7@4ax.com...

Kind of an off question, but I'm searching for a 60V CT (30-0-30)
transformer (1-2A is fine) for an amplifier I've been building. Would
I be better off just shelling out the cash and getting one, or is it
realtively easy to build your own (there are all sorts of torridial
cores avaliable at a local store, all for under 5$) I realize that
purchasing one would of course be the ideal situation, but I don't
particularily feel like spending 35$ for just a transformer... Anyone
have any recommendations where to look to buy one of these? Is
homebrewing one of these transformers relatively complicated? All
thoughs, including negative, are appreciated. Thanks in advance,
Steve

 

[James Sweet]

Don't try to wind your own mains transformer, it's just not a good idea. Buy
or salvage a commercially available one, it'll be much safer and easier.

<its you> wrote in message
news:j6kkhv40l1gkmio6knr6s2kc64rdh7bbh7@4ax.com...

Kind of an off question, but I'm searching for a 60V CT (30-0-30)
transformer (1-2A is fine) for an amplifier I've been building. Would
I be better off just shelling out the cash and getting one, or is it
realtively easy to build your own (there are all sorts of torridial
cores avaliable at a local store, all for under 5$) I realize that
purchasing one would of course be the ideal situation, but I don't
particularily feel like spending 35$ for just a transformer... Anyone
have any recommendations where to look to buy one of these? Is
homebrewing one of these transformers relatively complicated? All
thoughs, including negative, are appreciated. Thanks in advance,
Steve

 

Not sure is this will be relevant or helpful, but I know on a DMM I
have that has the continuity test built into the resistance test (are
on the same selection) will sound the buzzer when resistance drops
anywhere below about 3 ohms. So, it could be correct resistance, but
low enough to trigger the continuity test. 6.8 Ohms seems a tad high
to trigger continuity, but I imagine it's probably reading correctly.
Of course, to get a more accurate reading, you should remove one side
of the resistor and test them, this will tell you almost for sure if
the resistor is good (it could still be bad in varying temperature
conditions). I bet your DMM's reading correctly..
On Sun, 20 Jul 2003 03:40:06 GMT, "Andrew Camilleri"
<andrew@vallabeachresort.com.au> wrote:

Sorry I'm a bit of a newb to this and I am fixing a monitor

Also as a side note I have 3 resistors (flameproof) that test shorted with
the buzzer on my DMM but still have the right resistance values is this
normal (they are low value 2 x 1.2ohm and 6.8ohm) they all come from the HOT
emitter side and seem to connect to the chassis ground (through other
components).

Any help on this would be greatly appreciated.

Thanks in Advance

 

[Sam Goldwasser]

"Andrew Camilleri" <andrew@vallabeachresort.com.au> writes:

Sorry I'm a bit of a newb to this and I am fixing a monitor

Also as a side note I have 3 resistors (flameproof) that test shorted with
the buzzer on my DMM but still have the right resistance values is this
normal (they are low value 2 x 1.2ohm and 6.8ohm) they all come from the HOT
emitter side and seem to connect to the chassis ground (through other
components).

The buzzer on a DMM may consider 200 ohms to be continuity.

--- 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.

 

[Kevin Aylward]

R. Steve Walz wrote:

Kevin Aylward wrote:

R. Steve Walz wrote:


Its supported by the
10000's of bridges, millions of buildings, millions of roads, etc.
etc, all obviously designed and made by a consciousness, and such
that they could not have reasonable been built during my known
lifetime.
---------------------------------
But they don't exist when you're not looking at them.

Prove it.

Nor do they need to be "built again" for them to exist again.

If they don't exist, when not looking, then exist when looking, then
this is de facto that they need to be rebuilt. Dah..dont exist.. Dah..do
exist...

Jesus wept dude.

There's nothing wrong with them not being there when you're not
looking. You don't need them then!

It makes for a very complicated description of the universe. I prefer
Ocuums razor on this one.

The observabke is not suffecien

If it cannot be proved, it is not true,

Goedel says otherwise. You just don't seem to get this do you.
---------------------------------------
Goedel says it's not forbidden, which doesn't make it mandatory.
That's all.

Thats right, but you take the assumption that *nothing* is every true
without proof.

What I'm saying need not be proven either to be right.

It needs to be shown to be a useful view of the world. It isn't. Its
pretty much universally accepted that the universe is pretty much as we
see it. It allows me to make appointments with people who I don't happen
to see all the time.

it is an assumption based
on a poor understanding of natural law that will someday be
remedied,

Its based on a trivial application of the known laws. to wit, an
average brickie has 6 coffee breaks, plus lunch and afternoon tea,
leaving approximately 2hrs 45 minutes to swing his trawl.
-------------------------------------
Useless blathering again.

No, it points out the tremendous amount of useful knowledge and assumed
structure of the universe that would have to be given up by your
approach, for no sound reason.

per the Correspondence Principle of Science.

Someday it will be well-recognized that the physical laws MUST
include the observer or they are not true,

They already do and it is already well recognised. There is no
distinction whatsoever between the observed and the observer. They
are all made up of the same electrons, protons, Swiss cheese etc.
-----------------------------------
Nope. Stuff is something you sense, but what you are is thought.

Thought is nothing more than a physical process, centred in the brain,
just as any other physical process.

Now sensing is also just thought, but a separable category.


cannot be demonstrated in any but
a subjective circumstances, and that Personal Subjectivity is a firm
boundary condition upon the thing we call "Natural Physical Law".

Nonsense, wea generally all agree on things like 1, 2 ,3 etc..this is
objective.
----------------------------------
You see people saying that. Your subjective perception and belief.
You cannot prove anyone but you exists,

Ho humm. So what. You can't prove that only you exists. All, evidance
points to the contary.

you merely like the notion.

My emotions have zero to do with it.

Apparently RSW thinks otherwise. From time to time, I do observe
labourers building roads, bridges etc, it makes no rational sense
that these could all appear just for me.

Kevin Aylward
--------------------
If they had to appear other than when you saw them, you might be
right, but as strictly existing when you see them, they are just
part of what you are.

It makes no sense whatsoever, for things to disappear just because
they went out of my field of view.
------------------------
Have you ever seen "outside your field of view"? Of course not, you
CAN'T!

So what. The assumption that objects exist outside our view *never*
leads to contradictions. Absolutely never, so, its a very, very, good
assumption to make. To the contrary, to assume that objects don't exist
outside our view makes for a horrendous complication in understanding
even why it rains.

You have been completely suckered by this trivial notion of what you see
is green is not what I see as green etc... Sure, its an idea to discuss
down the pub, but is an entirely useless idea in practice. It has no
worth whatsoever. It has *never* lead to anything of use.

Sure, this could happen, in a the silly,
daft, absurd universe you live in, but certainly not for us sane
people.
--------------------------
You're claiming that your notional concept is somehow more sane
than mine which limits itself to observation.

It is.

Look, any child of 3 starts to learn that there is continuity in
objects. They don't get destroyed when you place them in a box. It
matters not one iota that it cant be proved. *You* cannot *prove*
otherwise.

But I'm not promoting solipsism, even though the argument can
support it in a contorted fashion.

Your supporting the nuthouse view of the universe.
-------------------------
No, it still works just fine.

No, it doesn't. There is no laws of physics with this view. No
conservation of mass-energy for example. Without laws of physics, we can
predict nothing. All you have is an ad-hoc collection of results. Its a
truly useless view of the universe

It simply sees natural law as participatory, and concreteness of
the physical as undemonstrable, which it is.

No. It removes physics. Period.

Instead I promote the notion of a Reality that has many facets,
called Ourselves, but whose natural laws are reflected ONLY in the
nature of these individuated facets, like a jewel. Natural laws
need only provide that what we see makes sense when we see it, and
not at any other time. Be honest!:

Nonsense. They need to make sense consistently.
-------------------------------
Makes fine sense to me,

Because your not sane.

things will be here when they have to be,
reliably, as always, I simply won't be entertaining silly assumptions
about when I'm not looking.

They are not silly assumptions. They are assumptions that *always* work.
End of story.

You are a right bloody idiot.
------------------
You're right bloody desperate and pitiable when you get this way.
You abandon reason and lash out like a toddler.

You cant reason with a bigoted idiot. Nah.Nah....Nah.Nah...Nah.....

There is NO way to prove the existence of
anything you're not able to see.

Irrelevant.
----------------------
Perhaps, but true. The danger of assumptions is too much for a
genuine scientist to merely stand by for.

Utter garbage. You have no idea of what a scientist or science is all
about. There is nothing wrong with assumptions. All scientists use them.
Special relativity is based on two simple assumptions. QM is based on a
few simple assumptions. The kinetic theory of gasses is based on simple
assumptions. *All* of science is based on assumptions. Without
assumptions, we would have nothing.

The issue is whether or not the assumptions are well founded or not.
Yours, i.e., that nothing exists unless you observe it, isn't. Its wild
speculation, without any evidence to support it whatsoever.

Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

 

[fidik]

It's probably cheaper to buy some scrap, there is usualy in each bigger city
some elctronics surplus store, try garage sales with odd equipment. Wires, core
and all that will probably cost more.

You can do it yourself, the biggest problem is inability to test the voltage
while you are making it, in order to test it you must almost complete it, then
you find that the voltages do not match with or without the load and then you
must take it apart again.

its, you wrote:

Kind of an off question, but I'm searching for a 60V CT (30-0-30)
transformer (1-2A is fine) for an amplifier I've been building. Would
I be better off just shelling out the cash and getting one, or is it
realtively easy to build your own (there are all sorts of torridial
cores avaliable at a local store, all for under 5$) I realize that
purchasing one would of course be the ideal situation, but I don't
particularily feel like spending 35$ for just a transformer... Anyone
have any recommendations where to look to buy one of these? Is
homebrewing one of these transformers relatively complicated? All
thoughs, including negative, are appreciated. Thanks in advance,
Steve

 

[Kevin Aylward]

Kevin Aylward wrote:

R. Steve Walz wrote:
Kevin Aylward wrote:

R. Steve Walz wrote:


Its supported by the
10000's of bridges, millions of buildings, millions of roads, etc.
etc, all obviously designed and made by a consciousness, and such
that they could not have reasonable been built during my known
lifetime.
---------------------------------
But they don't exist when you're not looking at them.

One also needs to point out the obvious here. There is *never* a time
when you aren't looking or observing everthing in the universe, so you
whole belief system is completely vacuous. Your arguing about a
situation that cannot ever occur, not ever in this universe.

An observer is *anything* that can detect *any* effect whatsoever. The
empire state building's gravitational field is having an effect on me
here in the uk. The em fields generated by you typing at your computer
effect my monitor. Of course, these effects are small, but the principle
remains the same. Objects are always, connected to every other object in
the universe, although with a delay. This connection means that you are
always an observer of everything.

Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

 

[Fred McKenzie]

<< Kind of an off question, but I'm searching for a 60V CT (30-0-30)
transformer (1-2A is fine) for an amplifier I've been building. Would
I be better off just shelling out the cash and getting one, or is it
realtively easy to build your own (there are all sorts of torridial
cores avaliable at a local store, all for under 5$) >>

Steve-

You would need a large, tape-wound toroidal core to operate at the power
frequency. A ferrite core is not likely to be adequate for your needs.

If I were trying to make my own transformer, I'd look for a junker that had the
desired power rating (120 watts in your case), and replace the secondary. To
be sure there is enough room to wind the new secondary, perhaps a higher power
transformer would give some margin.

You can wind a test secondary, measure voltage, and calculate the required
number of turns to get the voltage you want. Give it a little extra to account
for IR drop.

To ensure an exact center tap, you might wind two pieces of wire at once
(bifilar winding) and connect them in series-aiding.

Good luck.

Fred

 

[Peter Gottlieb]

There are a lot of design issues involved in winding a transformer - too
many to get into here in detail. Your basic issues are:

1) Core material and saturation level
2) Enough primary windings to get sufficient field but not saturate core.
3) Thickness of primary winding.
4) Isolation between primary and secondary.
5) Secondary winding - turns and thickness.
6) Losses and temperature rise.
7) Change of characteristics as temperature rises.
8) Making it fit on a particular core/bobbin.

Best would be to find a transformer of similar power level where the primary
is wound first and you can remove the secondary and replace with your own.

I have a big Excel spreadsheet somewhere which assists in transformer design
but I'm not sure I can still find it and it does require some knowledge and
experience to use.


<its you> wrote in message
news:j6kkhv40l1gkmio6knr6s2kc64rdh7bbh7@4ax.com...

Kind of an off question, but I'm searching for a 60V CT (30-0-30)
transformer (1-2A is fine) for an amplifier I've been building. Would
I be better off just shelling out the cash and getting one, or is it
realtively easy to build your own (there are all sorts of torridial
cores avaliable at a local store, all for under 5$) I realize that
purchasing one would of course be the ideal situation, but I don't
particularily feel like spending 35$ for just a transformer... Anyone
have any recommendations where to look to buy one of these? Is
homebrewing one of these transformers relatively complicated? All
thoughs, including negative, are appreciated. Thanks in advance,
Steve

 

[u1061771156]

In article <58b63b11.0307191830.609168c8@posting.google.com>, Netguy wrote:

Hi, guys,

You can contact newg@softhome.net for any of your FBT & hard-to-find components.
Very affordable.

So, what do you charge for this one?

u1061771156@csi.com (u1061771156) wrote in message news:<slrnbh0vnl.is.u1061771156@csi.com>...
In article <BB33DD72.96E5%kai.robinson@tiscali.fr>, Kai Robinson wrote:
Hey there! I did exactly as you said - and lo and behold - CLEAR PICTURE!!!
from a monitor from a Skip!! The quality is amazing - and it was such a
small adjustment - theres loads of range left in it as well - although i'll
order a spare flyback just in case - where did you get yours from? Cheers!!

Kai

I got it from PSA Parts ... June 2002:

"You can place a back order for 313812875530 on our web site. Price is
GBP60.00 + GBP6.80 carriage and the lead time is 7-10 days."

(Plus VAT of course).
Website is http://www.psaparts.co.uk/

At that price I'd _not_ recommend buying a spare while your existing one
is working OK. I'd be interested to hear if anyone knows of a cheaper
source ...

Mike.

 

I thought of stacking two commonly avaliable 30VCT transformers, but
didn't know if this was good practice. Any thoughts?
And, just out of curiousity, how would one go about winding a
torroidal transformer? would the primary and both secondaries all be
parallel windings, or would you wind one on one side and the other two
on the other? I probably won't do it myself, as I have a spare
amplifier with a transforemr that'll give me the voltages I need, but
the reason I'm building is to make a portable monitor, and space is
kind of tight...kind of really tight Thanks for the replies, Steve
On Sun, 20 Jul 2003 14:28:34 GMT, lcoe <lcoe@c1932201-a.attbi.com>
wrote:

its wrote:
Kind of an off question, but I'm searching for a 60V CT (30-0-30)
transformer (1-2A is fine) for an amplifier I've been building. Would
I be better off just shelling out the cash and getting one, or is it
realtively easy to build your own (there are all sorts of torridial
cores avaliable at a local store, all for under 5$) I realize that
purchasing one would of course be the ideal situation, but I don't
particularily feel like spending 35$ for just a transformer... Anyone
have any recommendations where to look to buy one of these? Is
homebrewing one of these transformers relatively complicated? All
thoughs, including negative, are appreciated. Thanks in advance,
Steve

how about stacking two bell xfmrs? the 18v model s/b close to what
you need and s/b cheap at Hdepot of Lowes. --Loren

 

[James Sweet]

how about stacking two bell xfmrs? the 18v model s/b close to what
you need and s/b cheap at Hdepot of Lowes. --Loren

You won't get enough current out of that for an amplifier, well unless it's
a rather small one.

Transformers can be stacked just fine though.