MessageView 421F schematic

[hubert roussel]

You would see an X-Y position on the time/div knob,and the ext trigger
input would become the X input.I don't have any T912 pix or a manual,so I
can't say that it does have this feature,and I can't recall if it does.

It was that!
Simply, to see something, it needs that X tensions are included between 0,5v
and 6v (approximately) and to turn intensity knob 45° clockwise.
Sorry (and thank you for these advices... ;o)
hr
--
http://www.photologie.net/
--

 

[Jim Adney]

On Thu, 14 Aug 2003 14:47:10 +0100 David Chapman
<dave@chassis.demon.co.uk> wrote:

Does anyone in this NG know who might be already producing a small,
portable, solid-state stereo tape recorder that has REMOVABLE flash
memory?

Not solid state, but how about a mini-disk recorder? They are only
slightly larger than the size you posted, and can do both recording
and playback. The ones I've seen do not include a microphone, though,
so an external microphone is required.

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

 

[Jim Adney]

On Wed, 13 Aug 2003 22:04:16 -0400 "ctsbillc"
<nospamctsbillc@ieee.org> wrote:

Band gap references are built into many voltage regulators, and they are
quite stable.

Can someone please explain to me the difference between a band gap
reference and a Zener?

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

 

[CWatters]

http://groups.yahoo.com/group/jallist/message/7099?source=1

Might be useful.

 

[Nam Paik]

"M. Hamill" <mhamill@fuse.net> wrote in message news:<3f3ea6f0$0$52159$a0465688@nnrp.fuse.net>...

Am I right to be concerned about aging and heat cycling of the electronics
and CRT? And do you have any ideas about what good intervals would be for
these settings? In my case I don't like to shut down my PC completely (it's
difficult to restart, and I leave it on overnight.)

Mike

30 minutes sounds like a good setting for computer/monitor to go into
power saving mode. I have my PC on similar settings, and have had no
problems with CPU and monitors going to "sleep" or "engergy-save" mode
and coming out of it with activity at keyboard/mouse. For example, TV
is turned on/off many times a day, yet no problems occur because of
this. A good surge protector or UPS should provide protection against
surges/spikes/voltage problems (there were reports of voltage swings
from 79 to 147 volts during the NY blackout last week and I would not
be surprised if many electronic appliances got damaged - since
acceptable limits are 100 to 132 volts)

 

[M]

"M. Hamill" <mhamill@fuse.net> wrote in message
news:3f3ea6f0$0$52159$a0465688@nnrp.fuse.net...

I've a few questions which I hope someone can help out on:

I have the following settings through Windows for my computer monitor and
PC:
- Monitor on low-power standby after 8 minutes (no screen saver used).
- Monitor shuts off after 36 minutes.
- PC in low-power standby after 36 minutes.

The monitor takes 90 watts of power normally, 5 watts in standby; the PC
power supply is 145 watts, unknown power usage in low-power standby.

I want to strike a good balance between saving electricity, and wear on
the
monitor CRT, monitor electronics and PC electronics. I'm concerned that
frequent switching between modes might be bad on the electronics of both,
and maybe the monitor's CRT. I've had this PC for 6 years and the only
problems seem to be in the power supply on startup, but otherwise it's
functional. My monitor is only 6 weeks old (previous one lasted nearly 6
years.)

Am I right to be concerned about aging and heat cycling of the electronics
and CRT? And do you have any ideas about what good intervals would be for
these settings? In my case I don't like to shut down my PC completely
(it's
difficult to restart, and I leave it on overnight.)

Mike

Monitors age in the following ways:
1) The cathode in the electron gun wears out leading to low contrast. This
occurs while the CRT is powered up regardless if a screensaver is used.
2) Using a screensaver can prevent burn-ins
3) Heat is damaging but thermal cycling is damaging too. My guess is that
CRTs dont deteriorate much from thermal cycling but electronics and the
flyback do.

As for the computer, at an age of 6 years it's probably not worth much. I'd
worry more about saving electricity than preventing thermal cycling.

-M

 

[Fred Abse]

On Fri, 15 Aug 2003 07:38:01 +0100, Boozo wrote:

What sort of cable can I use for a AF signal generator ?

It has a BNC connector for signal out and does sine/square wave and
various kilocycles etc...
It's made by Advance - England.

Any old cable you want that'll take a BNC.
You can intermix 50- and 75-ohm BNCs at where you're not bothered about
matching (like at audio) - they will intermate, unlike N types, which
won't.

--
Then there's duct tape ...
(Garrison Keillor)
nofr@sbhevre.pbzchyvax.pb.hx

 

[Boozo]

"Fred Abse" <excretatauris@cerebrumconfus.it> wrote in message
newsan.2003.08.20.20.19.00.94102.656@cerebrumconfus.it...

On Fri, 15 Aug 2003 07:38:01 +0100, Boozo wrote:

What sort of cable can I use for a AF signal generator ?

It has a BNC connector for signal out and does sine/square wave and
various kilocycles etc...
It's made by Advance - England.

Any old cable you want that'll take a BNC.
You can intermix 50- and 75-ohm BNCs at where you're not bothered about
matching (like at audio) - they will intermate, unlike N types, which
won't.

--
Then there's duct tape ...
(Garrison Keillor)
nofr@sbhevre.pbzchyvax.pb.hx

Thanks Fred, I thought as much but wanted to make sure.
Obviously not critical as the CRO probes but just in case.

Regards, Boozo.

 

[OFFICIAL RAM BLUEBOOK VAL]

On 25/8/03 6:20, in article 61d44658.0308241220.7923e0b@posting.google.com,
"Eric James Niemi" <eric@reactionmachine.com> wrote:

Would have tried e-mailing you but I didn't have your e-mail
address...

--
Robert Morein.



rho@netreach.net
prolog@comcast.com
prolog@comcast.net
south@netreach.net
north@netreach.net
prolog@netreach.net
prologue@netreach.net

 

[Robert Morein]

"Eric James Niemi" <eric@reactionmachine.com> wrote in message
news:61d44658.0308241220.7923e0b@posting.google.com...

Robert,

Would have tried e-mailing you but I didn't have your e-mail
address...

In your opinion would the following modification work?


http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=3CB4DFE9.8ED24524%40znet.com

I am trying to get the best sound I can with essentially "no budget"
but don't want to wreck a mic in the process if it doesn't work.

Hope you can give some info on this mod.
Sincerely,
Eric

The pros and conds:
Some evidence that the modification would flatten frequency response is
provided by the performance of Panasonic electret mic capsules, which are
frequently used -- though I can't rule out the possibility that Sony made
their own.

Even though the capsules have a window on one surface, they are essentially
omnidirectional except at high frequencies. Omnidirectional microphones have
flatter, more extended response than microphones mounted in such a way as to
give polar response. These capsules, which cost only a few dollars, have
extremely flat response up to, and in some cases, past 20 kHz. This is
partly a property of the capsule, and partly of omindirectional microphones
in general.

The MS-907 is a cardiod mic. Exposing the capsule would remove the polar
pattern, and result in an essentially omnidirectional microphone. Although
this would extend the frequency response, omni mics are useless for location
sound recording, except as lapel mics, because of the excessive intrusion of
ambient sound.

In a very quiet studio, with controlled reflectivity, omnidirectional mics
can be golden, because of their flat, extended response. Such is not the
case here.

The reason Sony was not able to accomplish the frequency response you want
is because small electret capsules have high self-noise. This is the noise
generated by individual air molecules hitting the diaphram, as well as noise
generated within the FET preamp that is also contained in the mic capsule.

Expensive microphones have flatter response because they have lower self
noise, which allows the designers more freedom in the design of the polar
pattern enclosure. This is the reason that despite improvements in recent
years, electret mics have never been able to equal the performance of either
DC condenser mics, or the AC condenser proprietary to Sennheiser.

 

[Eric James Niemi]

"Robert Morein" <nowhere@nowhere.com> wrote in message news:<itGdnf9mzNDKt9SiXTWJhg@comcast.com>...

The pros and conds:
Some evidence that the modification would flatten frequency response is
provided by the performance of Panasonic electret mic capsules, which are
frequently used -- though I can't rule out the possibility that Sony made
their own.

Even though the capsules have a window on one surface, they are essentially
omnidirectional except at high frequencies. Omnidirectional microphones have
flatter, more extended response than microphones mounted in such a way as to
give polar response. These capsules, which cost only a few dollars, have
extremely flat response up to, and in some cases, past 20 kHz. This is
partly a property of the capsule, and partly of omindirectional microphones
in general.

The MS-907 is a cardiod mic. Exposing the capsule would remove the polar
pattern, and result in an essentially omnidirectional microphone. Although
this would extend the frequency response, omni mics are useless for location
sound recording, except as lapel mics, because of the excessive intrusion of
ambient sound.

In a very quiet studio, with controlled reflectivity, omnidirectional mics
can be golden, because of their flat, extended response. Such is not the
case here.

The reason Sony was not able to accomplish the frequency response you want
is because small electret capsules have high self-noise. This is the noise
generated by individual air molecules hitting the diaphram, as well as noise
generated within the FET preamp that is also contained in the mic capsule.

Expensive microphones have flatter response because they have lower self
noise, which allows the designers more freedom in the design of the polar
pattern enclosure. This is the reason that despite improvements in recent
years, electret mics have never been able to equal the performance of either
DC condenser mics, or the AC condenser proprietary to Sennheiser.

Wow! Great info... Thanks for the quick response. Yes, if it becomes
an omni mic it wouldn't help me at all even if the freq. response got
better. Using it for film/video application where I would need some
directional control.

You saved me from possibly ruining a good mic, thanks again Robert.
Sincerely,
Eric

 

[CWatters]

Like this perhaps.. They have variois other ranges.

http://www.connectdsc.com/series.asp?SeriesID=by05


"CJT" <cheljuba@prodigy.net> wrote in message
news:3F5049C6.1000604@prodigy.net...

Bob Morein wrote:

I have an experimental rig I need to instrument with delicate strain
gauge
wires and other sensors, attached to plastic pipes.
I'm looking for connectors that will allow segmenting the wiring.
They need to be balanced, ie., 2 conductor + braid, should be smaller
than
XLR, and it would be nice if they were easy to wire up.

I don't think that minature 3 conductor mic plugs are robust enough for
this.

Any suggestions?



I'd be concerned about thermal emf every time you change metals.

 

[Harvey White]

On Sat, 30 Aug 2003 01:17:06 -0400, "Bob Morein" <nowhere@nowhere.com>
wrote:

I have an experimental rig I need to instrument with delicate strain gauge
wires and other sensors, attached to plastic pipes.
I'm looking for connectors that will allow segmenting the wiring.
They need to be balanced, ie., 2 conductor + braid, should be smaller than
XLR, and it would be nice if they were easy to wire up.

I don't think that minature 3 conductor mic plugs are robust enough for
this.

Miniature DIN connectors. How much do you plan to connect/disconnect
these, and how much strain do you think they will be under?

Harvey

Any suggestions?

 

[Bob Morein]

"Harvey White" <madyn@ix.netcom.com> wrote in message
news:qmi1lv4f7tlplpgnh7c28i7e2an3uuliue@4ax.com...

On Sat, 30 Aug 2003 01:17:06 -0400, "Bob Morein" <nowhere@nowhere.com
wrote:

I have an experimental rig I need to instrument with delicate strain
gauge
wires and other sensors, attached to plastic pipes.
I'm looking for connectors that will allow segmenting the wiring.
They need to be balanced, ie., 2 conductor + braid, should be smaller
than
XLR, and it would be nice if they were easy to wire up.

I don't think that minature 3 conductor mic plugs are robust enough for
this.


Miniature DIN connectors. How much do you plan to connect/disconnect
these, and how much strain do you think they will be under?

Harvey


Any suggestions?

The connector should have at least passive locking, ie., a detent that keeps

it snug, since vibration could be a problem.
My experience with mini-din is that they work loose very easily.

 

[Jim Yanik]

Rich Andrews <n0-spam@yah0o.com> wrote in
news:Xns93E88502CF9D3mc2500183316chgoill@216.168.3.44:

Well, I changed the CRT and the problem is now gone. The mesh in the
old crt is distorted is my guess. Strange!

r

The mesh lens is a dome-shaped,very thin,fine screen,and if the scope is
shocked in certain axis,the lens could distort.Perhaps by setting the scope
down hard on it's end,in transporting it,but I am not certain of that.

--
Jim Yanik,NRA member
jyanik@kua.net

 

[CWatters]

"Bob Morein" <nowhere@nowhere.com> wrote in message
news:NSadncmJMu1Ylc-iXTWJkQ@comcast.com...

The connector should have at least passive locking, ie., a detent that
keeps
it snug, since vibration could be a problem.
My experience with mini-din is that they work loose very easily.

I spent a long time looking for 2+E bayonet connectors earlier this year....
and couldn't find any really small/cheap ones. The best I managed were
these. links..

http://dkc3.digikey.com/PDF/T023/V5/0169.pdf (12mm overall)

http://www.connectdsc.com/series.asp?SeriesID=by05 (13mm diameter).

The 400 Series Buccaneer range (19mm) are threaded and waterproof.

http://www.bulgin.co.uk/Products/Buccaneer/Buccaneer_400_Series.html

This site also has some small ones hidden away with the big military style
connectors.

http://www.lemo.com/

... but I expect they are expensive.

 

[Bob Morein]

Thanks. I'm thinking maybe the Hirose series of plastic connectors.
They're cheap, easy to work with, and have passive detent locking.


"CWatters" <colin.watters@pandora.be> wrote in message
news:%VH4b.12989$FC1.574592@phobos.telenet-ops.be...

"Bob Morein" <nowhere@nowhere.com> wrote in message
news:NSadncmJMu1Ylc-iXTWJkQ@comcast.com...

The connector should have at least passive locking, ie., a detent that
keeps
it snug, since vibration could be a problem.
My experience with mini-din is that they work loose very easily.


I spent a long time looking for 2+E bayonet connectors earlier this
year....
and couldn't find any really small/cheap ones. The best I managed were
these. links..

http://dkc3.digikey.com/PDF/T023/V5/0169.pdf (12mm overall)

http://www.connectdsc.com/series.asp?SeriesID=by05 (13mm diameter).

The 400 Series Buccaneer range (19mm) are threaded and waterproof.

http://www.bulgin.co.uk/Products/Buccaneer/Buccaneer_400_Series.html

This site also has some small ones hidden away with the big military style
connectors.

http://www.lemo.com/

.. but I expect they are expensive.

 

[Rich Andrews]

Jim Yanik <jyanik@abuse.gov> wrote in news:Xns93E8BE0112CC6jyanikkuanet@
204.117.192.21:

Rich Andrews <n0-spam@yah0o.com> wrote in
news:Xns93E88502CF9D3mc2500183316chgoill@216.168.3.44:




Well, I changed the CRT and the problem is now gone. The mesh in the
old crt is distorted is my guess. Strange!

r



The mesh lens is a dome-shaped,very thin,fine screen,and if the scope is
shocked in certain axis,the lens could distort.Perhaps by setting the
scope
down hard on it's end,in transporting it,but I am not certain of that.

I am surprised how little there is to hold the crt in place. Changing the
CRT is about the easiest job in servicing that series.

r


--
"Any sufficiently advanced technology is indistinguishable from
magic."

Arthur C. Clarke (1917 - ), "Technology and the Future"

 

[Harvey White]

On Mon, 01 Sep 2003 23:07:22 -0700, David Rutherford
<drutherford@softcom.net> wrote:

Rich Andrews wrote:

David Rutherford <drutherford@softcom.net> wrote in news:3F53F224.6B669169
@softcom.net:

I purchased a little (oscilloscope?) monitor (5" screen) at a local
electronics supply store and am trying to get it to work. It came with a
mostly unreadable schematic that, according to a local TV repairman, is
not the correct one.

The manufacturer of the monitor is not printed anywhere on it, as far as
I can tell, so I can't contact them to get the correct schematic.
However, a schematic might not be necessary for what I need to do.

What I'm trying to do is get the electron gun to direct the electron
beam at the center of the screen. First, though, I need to find out how
to get it to operate. It's just a crt connected to a circuit board and
metal frame - no on/off switch. There's a 10-pin terminal on the circuit
board, but I don't know which pins are for what. There are also controls
for video center, v-hold, v-height, v-lin, and sub-bright.

Any help would be appreciated. Thanks.

Dave Rutherford


I am not sure what you inteded purpose is, but there is a fair amount of
information you are going to have to verify. I would start with a pinout
of the CRT, a verification of the existence of a power supply. and then
determine if the unit runs on 12 VDC, 120 VAC or some other voltage. This
can be a rather tedious chore. If it is as somple as you say it is, it
sounds like there is not power supply. If you don't have a power supply
for the beast, then it is only good for parts AFAIC.

Thanks, Rich. I actually have two of them - each one with a CRT from a
different manufacturer. One CRT is made by Matsushita, the other is made
by Toshiba. There is no power supply with them - just the metal frame,
circuit board, and CRT.

The electronics store had a schematic and a monitor circuit card detail
laying with the monitors (these, apparently, weren't the right ones,
though, since the solder lines don't match). On the monitor circuit card
detail, however, a + 12V power source was called for. I'll try to draw
it here from what I can make out (it's a little blurred),

------ system gnd
------ }
------ } optional remote brightness control
------ }
------ special application
------ horiz. drive in
------ + 12V in
------ video in
------ vert. drive in

------ system gnd

Are these standard pin assignments or do they usually differ from unit
to unit? Also, what kind of 'video in', if any, would I need if I just
want to have a constant intensity electron beam always pointing at the
center of the screen (no modulation)?

Whether they are standard assignments I cannot say. However, these
are not oscilloscope monitors, they are television monitors. They
must scan, and you cannot have a constant intensity electron beam
pointing at the screen.

Vertical sweep is always on, and is fixed at 60 Hz. Horizontal sweep
is generated from an external oscillator, and is used to derive the
high voltage.

Because the horizontal sweep is driven, the components in the monitor
can be damaged with improper drive.

These were made to be driven directly from a CRT display controller
chip, such as the Motorola 6845 or the 6847. Video can be a TTL
level video, I think, and the drive signals can also be TTL level.

Since the 6845 and 6847 (for example) do not put out the proper
signals without programming, this monitor is designed to be the
display for a system that has a microprocessor, one of the two display
chips, and enough programming to make it work right.

It will not work with your computer unless you can provide it with the
right drive signals, and at the right frequency. Even then, it will
work with only the lowest resolution and in black and white.

Harvey

I'm not very familiar with electronics, so I hope you won't mind if I
ask some basic questions. Can you point me to a website where I can
learn more about this kind of thing? Thanks.

Dave


r

--
"Any sufficiently advanced technology is indistinguishable from
magic."

Arthur C. Clarke (1917 - ), "Technology and the Future"

 

[David Rutherford]

Harvey White wrote:

On Mon, 01 Sep 2003 23:07:22 -0700, David Rutherford
drutherford@softcom.net> wrote:

Thanks, Rich. I actually have two of them - each one with a CRT from a
different manufacturer. One CRT is made by Matsushita, the other is made
by Toshiba. There is no power supply with them - just the metal frame,
circuit board, and CRT.

The electronics store had a schematic and a monitor circuit card detail
laying with the monitors (these, apparently, weren't the right ones,
though, since the solder lines don't match). On the monitor circuit card
detail, however, a + 12V power source was called for. I'll try to draw
it here from what I can make out (it's a little blurred),

------ system gnd
------ }
------ } optional remote brightness control
------ }
------ special application
------ horiz. drive in
------ + 12V in
------ video in
------ vert. drive in

------ system gnd

Are these standard pin assignments or do they usually differ from unit
to unit? Also, what kind of 'video in', if any, would I need if I just
want to have a constant intensity electron beam always pointing at the
center of the screen (no modulation)?

Whether they are standard assignments I cannot say. However, these
are not oscilloscope monitors, they are television monitors. They
must scan, and you cannot have a constant intensity electron beam
pointing at the screen.

Vertical sweep is always on, and is fixed at 60 Hz. Horizontal sweep
is generated from an external oscillator, and is used to derive the
high voltage.

Because the horizontal sweep is driven, the components in the monitor
can be damaged with improper drive.

These were made to be driven directly from a CRT display controller
chip, such as the Motorola 6845 or the 6847. Video can be a TTL
level video, I think, and the drive signals can also be TTL level.

Since the 6845 and 6847 (for example) do not put out the proper
signals without programming, this monitor is designed to be the
display for a system that has a microprocessor, one of the two display
chips, and enough programming to make it work right.

It will not work with your computer unless you can provide it with the
right drive signals, and at the right frequency. Even then, it will
work with only the lowest resolution and in black and white.

Harvey

I think putting all of your valuable suggestions to work might be a bit
much for my meager electronics abilities. I may have to try some other
way of doing what I need to do. Thanks, Harvey, for all your help.

Dave