MessageView 421F schematic

[tom]

Mike Harrison <mike@whitewing.co.uk> wrote in message news:<6i3biv0vmjqkfmr61p45o6dmff8ijl1s30@4ax.com>...

Just took apart my Metcal MX2 PSU out of curiosity, and found a little pushbutton switch inside,
which is operated by a small grubscrew in the side of the case - anyone know what it's for...?
I don't have the original manual so I don't know if there's any mention of it in there....

If I remember correctly the switch in my MX-1 is for enabling or
disabling the auto shut off function of the power.


Tom

 

[bg]

When you move the trace up, you are adding a DC offset to the verticle amp.
This might cause a distortion in the amp for some oddball reason. You really
need to put another scope on the X and Y amps to see whats comming out. If
its clean then you do have CRT problems , magnetized shields or even a
static charge on the graticule. My scope gave me hell with bad connections
on the verticle amp board. There is a transistor array housed in a can about
the size of a quarter. It is a plug in device, which at times became a
"plug out" --- Every time I got the scope apart , this sucker just happened
to make contact and everything worked fine. Then a few months later it would
decide to yank my chain again. Thanks to solder, it won't be giving me
anymore headaches.
bg
Rich Andrews wrote in message ...

"bg" <bg@nospam.com> wrote in news:bh71e9$o55$1@terabinaries.xmission.com:

I've had similiar looking problems on my 465 when filter caps went bad.
Don't remember offhand which caps, but I do recall they were near they
HV section , blue and perhaps 200 volt or better. The bottom JPG looks
like you have both time bases switched in, that could be normal. You
probably need a second scope to look at your sweep signal.


The bottom signal is clear and straight. When you move the trace up on the
screen to the top 1/3, it is distorted.

r


bg
Rich Andrews wrote in message ...
I have a stange distortion on a 465 that I picked up recently. At first
glance I thought there was a power supply issue or a vertical amp
problem, but now I think it is the CRT. Can anyone confirm my
suspicions? I
posted
pics of the display on alt.binaries.schematics.electronic.


r


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

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







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

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

 

[Rich Andrews]

"bg" <bg@nospam.com> wrote in news:bh94cu$kjh$1@terabinaries.xmission.com:

When you move the trace up, you are adding a DC offset to the verticle
amp. This might cause a distortion in the amp for some oddball reason.
You really need to put another scope on the X and Y amps to see whats
comming out. If its clean then you do have CRT problems , magnetized
shields or even a static charge on the graticule. My scope gave me hell
with bad connections on the verticle amp board. There is a transistor
array housed in a can about the size of a quarter. It is a plug in
device, which at times became a "plug out" --- Every time I got the
scope apart , this sucker just happened to make contact and everything
worked fine. Then a few months later it would decide to yank my chain
again. Thanks to solder, it won't be giving me anymore headaches.
bg

I am going to try that. Until I get a second scope, if I reverse the vetical
leads on the CRT and the problem stays at the top of the crt, then vert. amp
issues would be ruled out then, yes?

I wonder if I still have that handheld 1" tape demagnetizer here
somewhere....


r

Rich Andrews wrote in message ...
"bg" <bg@nospam.com> wrote in
news:bh71e9$o55$1@terabinaries.xmission.com:

I've had similiar looking problems on my 465 when filter caps went
bad. Don't remember offhand which caps, but I do recall they were near
they HV section , blue and perhaps 200 volt or better. The bottom JPG
looks like you have both time bases switched in, that could be normal.
You probably need a second scope to look at your sweep signal.


The bottom signal is clear and straight. When you move the trace up on
the screen to the top 1/3, it is distorted.

r


bg
Rich Andrews wrote in message ...
I have a stange distortion on a 465 that I picked up recently. At
first glance I thought there was a power supply issue or a vertical
amp problem, but now I think it is the CRT. Can anyone confirm my
suspicions? I
posted
pics of the display on alt.binaries.schematics.electronic.


r


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

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







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

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

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

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

 

[Michael A. Terrell]

ctsbillc wrote:

Methinks you do'nt know how little you know.

This poor guy is not in a production test environment looking to see if the
output of a cellphone falls within a template, he is new to electronics, and
does not even know what Nyquist criteria are, of the difference between a
Hanning window and a Hamming.

Try to talk politely if you want a polite reply. You never know, you might
learn something.

Gee I'm not sure who you are replying to, but cell phones? I never
worked with them. In fact, I never called back the place that offered me
a job repairing them.

I worked on the military radios at Cincinnati Electronics, (PRC-77,
GRC-106). I did two way radio repair, CATV headend work, and designed
CATV system extensions. I designed a very simple cable system to
interconnect the community loops between different CATV companies. The
standard design was either two HSP's, or pairs of demodulators and
modulators, but my design used a single HSP (Heterodyne Signal
Processor) that was mounted in a large NEMA cabinet on a CG&E power pole
in Cincinnati, Ohio. 120 VAC power, and two ž inch 75 Ohm hard lines
entered the box. A four way splitter was used to connect the input and
output of the HSP to the two hard lines to connect a sub split system to
a mid split system. Everyone insisted it wouldn't work, but it did, and
the levels were within ˝ db when it was turned on.

I spent a number of years at Microdyne working as both a production
and an engineering tech. I wrote a lot of test procedures for the
RCB-2000 DSP based telemetry system, and updated the test procedures for
the older products, including the 1200, 1400, and 700 series.

I designed and built some of the RCB-2000 test fixtures as well as
configuring a system to install and test the RCB-2000 on the in plant
computer network. A tech in final test could call engineering and give
them the serial number. The engineers or programers could log into the
RCB2000 to verify that it had the proper software installed for the
individual customers specifications.

http://www.l-3com.com/te/PDF/Microdyne/RCB-2000.pdf

Some people have no problem walking up to a new piece of equipment and
can figure out how to use it in a couple minutes. On the other hand,
there are others who can NEVER be taught how to do some simple jobs.

I worked part time in a TV shop while I was in Jr. high school. I
used and repaired ˝ inch reel to reel B&W video tape equipment in the
late '60s while I was in high school.

I was drafted in Aug. 1972, and the US Army awarded me a broadcast
engineer rating while I was in basic training. Then they sent me off to
repair CATV, microwave relay equipment (CARS), AM & VHF TV broadcast
equipment, as well as a few cranky Korean war vintage radar systems when
the RADAR section was short handed.

I have absolutely no formal training in electronics but I have
studied the field on my own since I turned 13.

You have your opinions, and I have mine. I have worked with a few
really good engineers, and with plenty who threw together a haywire
prototype, tossed the notes to drafting, and refused to admit any
mistakes, including one where they signed off the design of a $400
custom chassis. The drawing backwards, so it we it was a mirror image
when it arrived at his desk to assemble the pair of prototypes.

A degree means You SHOULD know what you are doing, but it doesn't
guarantee you know anything. This applies to engineers, doctors, or any
other field you can think of.

I can only remember one time I ever needed a manual to figure out a
function on a piece of test equipment, and then when I found the right
part of the manual it was wrong. I had to configure a HP network
analyzer to use a Think jet printer with an IEEE -488 (HPIB) interface.
It took a little while to find that it was in a different menu than the
one specified in the manual. After I figured it out, Design engineering
heard about it and came out to the test department to ask how to make it
work for them.



--


Michael A. Terrell
Central Florida

 

[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.

Yes, it should be something like that...
Some T912 pictures here :
<http://perso.wanadoo.fr/hubert.roussel/tektronix/tektronix.html>
Thanks... ;o)

 

[Jim Yanik]

hubert roussel <h.roussel@wanadoo.fr> wrote in
news:BB5E7A97.5A52E%h.roussel@wanadoo.fr:

Hello,

One month ago, I found on ebay this oscilloscope, but without manual.

Could anybody say to me if Tektronix T912 works in XY mode, and, if it's
possible, how can it be done ?

Thanks ! ... ;o)
hr

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.

--
Jim Yanik,NRA member
remove null to contact me

 

[Grant Erwin]

Most people use tin foil to protect from such. Works pretty well
tucked inside the helmet and inside the underwear. - GWE

Mark wrote:

I have a brother that I'm afraid is a paranoid schizophrenic. He's
convinced that people that are close to him are doing things to his
house to "shoot stuff" at him.

Why am I posting this in here?

I want to see if it is at all possible to use some kind of "silicone
dust" to rub it onto and in the walls, carpet, ceiling and have it
controlled through infrared remote controllers for tv, dvd, cell
phone, playstation (or insert any other electronic item here) to be
able to inflict harm on an individual. It sounds far out, but I just
want to help my brother.

Please respond either here or directly to cvetsnareatyahoodotcom.

Thank you,

Mark

 

[Fred Abse]

On Tue, 12 Aug 2003 20:16:26 +0100, Grant Erwin wrote:

Most people use tin foil to protect from such. Works pretty well tucked
inside the helmet and inside the underwear. - GWE

Works best with WWII German helmets. Ask any Hell's Angel.

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

 

[ctsbillc]

I missed the first part of this, so sorry if some of this has already been
said.

You cannot do immunity testing, even as low as 1 V/m, without a shielded
enclosure - you will exceed the fcc limits, which are in the region of a
miilivolt/m or less (dependant of standard and frequency.

Generally, precompliance testing is limited to a spectrum analyser and a
calibrated antenna, as you are much more likely to fail Radiated Emissions
that you are Radiated Susceptibility (in the commercial world anyway).

Last time I ran a commercial EMC lab, about 2/3rd of customers failed
Radiated Emission first time through.

Regards,

Bill C


"hammy" <email@hotmail.com> wrote in message
news:Xns93A2AFA72C77Bhammy@205.215.62.132...

qu1nn@buffalo.com (qu1nn) wrote in news:417b2fd1.0306200904.5444a44
@posting.google.com:

First Question:
you mention that broadband transmissions created in an unshielded
environment could block out services....
Living in NY state...
* what is max power that can be dissipated and NOT interfere?
* what is the max safe level for human exposure?

------------------------
Tems Cell:
I did some looking up on this and the EUT is larger than most of the
available equipment that is on the market. (need some 4' x 4' area)

Also this is pre-compliance testing .. so I need to keep costs down.

-----------------------

Thanks for the Agilent reference, it led me to find many articles on
how to use near field probes at a lower power so as not to cause any
health / FCC issues. This method may provide me with additional
clues. ( This too would go along with the radiated emissions approach
that you mention)

Qu1nn


Glad the Agilent reference was useful to you.

If you want to know what are defined as safe linits for exposure, I can
recommend the Narda site at
http://www.narda.de/en/basiswissen/grenzwerte.htm
This has a graphical representation of the recommended limits and links
to the relevant safety autorities.

As for what level will not cause interference,this would be the same
levels specified in the emission levels for EMC conformance.

Sorry the TEMS cell approach won't work for you, but with the size of EUT
you have you would need a full screened room.


-x- 100 Proof News - http://www.100ProofNews.com
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[CWatters]

"Mark" <gohabeeb@my-deja.com> wrote in message
news:850dccd.0308120933.5200e381@posting.google.com...

I have a brother that I'm afraid is a paranoid schizophrenic. He's
convinced that people that are close to him are doing things to his
house to "shoot stuff" at him.

Yeah we've seen 1000's of his posts on news groups but none recently.

The answer to your other question is no - or at least not yet.

 

[Harvey White]

On Wed, 13 Aug 2003 13:02:32 -0400, "Jonathan"
<jonathanNOFISH@sprintmail.com> wrote:

On Wed, 13 Aug 2003 13:02:32 -0400, in sci.electronics.equipment you
wrote:

Hi,
I'm looking to pick up a scope. It will be mostly for bench use, and will
not be used heavily. It's really to help me out as I try to get back into
doing some simple microcontroller and TTL projects in my garage... that type
of thing.

OK, microcontrollers you'll need to look at 24 mhz or so squarewaves
(clocks). Most data busses are around 10 mhz or below.

Now, of course money is a factor. And although it looks like used analog
scopes can be had for anywhere from say $75 - $300 or more, the digital
scopes can be found on eBay for not too much more. I have to admit, the
compact size of the Fluke Scopemeters is attractive.

You do have to watch out for the digital scopes. They are not the
same kind of animal an analog scope is. One is that the sampling
frequency and rate are critical for observing a waveform. One plus is
that a digital scope has storage capabilities.

So would something like an old Scopemeter 97 be a good choice? It's got
decent bandwidth and such. Are these units reliable, and safe to buy used?
Advice/experiences appreciated....

Single channel 10 mhz LCD type portable scope (velleman -10 model), 1
channel, 2 memories, no digital outputs. roughly 160 or so at
www.allelectronics.com and look at the test equipment. Runs off 5
nicads. Decent, but I wouldn't want it for my only scope.

if you want to go digital, and you will be doing microprocessor stuff,
you might want to check out an HP 1631D logic analyzer. 2 channel 50
mhz digital scope included. Be absolutely sure you get the pods and
grabbers with it... can be had for roughly 200 to 400 depending on
condition. 48 channel logic analyzer, btw....

Analog scopes... generally steer clear of Telequipment, quality
varies, avoid T900 stuff. Tektronix is good, a 7000 series mainframe
with plugins and readouts is good, 5000 series is lower cost and
bandwidth, avoid -N series if you want on screen readouts.... Costs
and capabilities vary, you will need a timebase and a vertical plugin
at the least.

Digital I don't really know about, but they can be expensive as well..

Harvey

thanks,
Jonathan

 

[Grant Erwin]

I recently faced this issue. I wound up buying TWO Tek 2445s, one for a
parts scope since so many of the Tek parts are now made of unobtainium.
My total cost was about $450 and I have a good clean working 2445B which
is substantially complete. Took awhile, though.

Grant Erwin
Kirkland, Washington

Jonathan wrote:

Hi,
I'm looking to pick up a scope. It will be mostly for bench use, and will
not be used heavily. It's really to help me out as I try to get back into
doing some simple microcontroller and TTL projects in my garage... that type
of thing.

Now, of course money is a factor. And although it looks like used analog
scopes can be had for anywhere from say $75 - $300 or more, the digital
scopes can be found on eBay for not too much more. I have to admit, the
compact size of the Fluke Scopemeters is attractive.

So would something like an old Scopemeter 97 be a good choice? It's got
decent bandwidth and such. Are these units reliable, and safe to buy used?
Advice/experiences appreciated....

thanks,
Jonathan

 

[Harvey White]

On Wed, 13 Aug 2003 16:55:34 -0700, Lizard Blizzard <NOSPAM@rsccd.org>
wrote:

Bill Janssen wrote:

Alan Horowitz wrote:


any of these new-fangled battery chemistries such that, buying an
average one off the shelf, it has a voltage that's within 1% of it's
nominal?


Check the spec.'s on coin size Mercury cells. As I remember a new
one has a well defined voltage.

Mercury cells cannot be sold because of the mercury in them. So the
battery could not be purchased, as the OP requested.

Possibly the lithium cells instead

If you really wanted to do it right, you could get a voltage reference
chip that had a known voltage (I suspect, haven't managed to remember
the specs for that.

Harvey

Good luck.
Bill K7NOM

 

[ctsbillc]

I suspect a regulator is the best way. The battery approach is possible,
but not if you want a reasonable current draw.

The Weston standard cell is the best battery for a stable voltage, as I
recall from long ago.

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

Bill C

"Harvey White" <madyn@ix.netcom.com> wrote in message
news:2mpljv09a6tjnmqkiagaicaodfrb80rlta@4ax.com...

On Wed, 13 Aug 2003 16:55:34 -0700, Lizard Blizzard <NOSPAM@rsccd.org
wrote:

Bill Janssen wrote:

Alan Horowitz wrote:


any of these new-fangled battery chemistries such that, buying an
average one off the shelf, it has a voltage that's within 1% of it's
nominal?


Check the spec.'s on coin size Mercury cells. As I remember a new
one has a well defined voltage.

Mercury cells cannot be sold because of the mercury in them. So the
battery could not be purchased, as the OP requested.


Possibly the lithium cells instead

If you really wanted to do it right, you could get a voltage reference
chip that had a known voltage (I suspect, haven't managed to remember
the specs for that.

Harvey






Good luck.
Bill K7NOM

 

[Harvey White]

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

I suspect a regulator is the best way. The battery approach is possible,
but not if you want a reasonable current draw.

The Weston standard cell is the best battery for a stable voltage, as I
recall from long ago.

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

that's what I was thinking of...

Harvey

Bill C

"Harvey White" <madyn@ix.netcom.com> wrote in message
news:2mpljv09a6tjnmqkiagaicaodfrb80rlta@4ax.com...
On Wed, 13 Aug 2003 16:55:34 -0700, Lizard Blizzard <NOSPAM@rsccd.org
wrote:

Bill Janssen wrote:

Alan Horowitz wrote:


any of these new-fangled battery chemistries such that, buying an
average one off the shelf, it has a voltage that's within 1% of it's
nominal?


Check the spec.'s on coin size Mercury cells. As I remember a new
one has a well defined voltage.

Mercury cells cannot be sold because of the mercury in them. So the
battery could not be purchased, as the OP requested.


Possibly the lithium cells instead

If you really wanted to do it right, you could get a voltage reference
chip that had a known voltage (I suspect, haven't managed to remember
the specs for that.

Harvey






Good luck.
Bill K7NOM

 

[Harvey White]

On Thu, 14 Aug 2003 02:38:34 +0000 (UTC), Jim Yanik
<jyanik@nullkua.net> wrote:

For a beginning hobbyist scope a T922 (15Mhz) or T932/35 (35Mhz) would be a
inexpensive,reasonable choice,very serviceable,contains no TEK-made ICs
that are no longer made. (like 7K or later 400 series)

Ok, never had a 7000 series, so that's a good reason not to get one...
probably have to really work to figure out what was in them.... how
special... guess I'd have to get two if I needed to have one.

Never had the 900 series, but remember the early ones... I think I was
thinking of a 912 or so....

Or look for a 2213/15 or 2235.

some people like them, some don't. I actually went with a Kenwood
that was in good shape, and had lots of goodies.

I would avoid a T912(10 Mhz) storage scope,though,and 434's.(25 Mhz)

5000 series scopes are either 2 Mhz (5100)or 50 Mhz BW (5400),and were
crap.

I think that there were some 10-20 Mhz ones, but that's just a memory
and I can't attest to the accuracy of it....

If he wanted a digital scope,I'd try to find a TDS200 series or their newer
equivalent.

got out of the market before that happened... so thanks anyway,
though, for the information. Tends to be useful when I see this stuff
at a hamfest... however, with 2 benchtop scopes, 2 portable scopes,
and a logic analyzer I actually don't *need* another scope.... I
don't.... I really don't....

Harvey

 

[Jim Yanik]

Grant Erwin <grantNOSPAM@kirkland.net> wrote in
news:vjl2hm7b4au04c@corp.supernews.com:

I recently faced this issue. I wound up buying TWO Tek 2445s, one for
a parts scope since so many of the Tek parts are now made of
unobtainium. My total cost was about $450 and I have a good clean
working 2445B which is substantially complete. Took awhile, though.

Grant Erwin
Kirkland, Washington

2445/65 series were the best analog portable scope ever made.



--
Jim Yanik,NRA member
remove null to contact me

 

[Harvey White]

On Thu, 14 Aug 2003 15:45:01 GMT, Bill Janssen <billj@ieee.org> wrote:

Lizard Blizzard wrote:

Oh, I wasn't aware that Mecury cells were no longer available.

Alkaline batteries, a while back, had a big "mercury free" sticker on
them.

They've been replaced by silver oxide cells, I think.

Mercury used to have 1.35 volts, rather reliably, and many circuits
were set for that (photometers in cameras, for instance). Silver
oxide is 1.5 volts, I think, but I haven't heard of too much of a
problem.

However, go price watch batteries... Uniformly overpriced at 3
USD/each at RadioShack(tm), and about a dollar less at Wally World
(wal-marts).... only if you dig them out of the electronics section.
Buy them at the watch counter, and they're 3 dollars each, which
includes installation...

Decline installation, and they're still 3 dollars each.

Harvey


>

 

[Fred Abse]

On Thu, 14 Aug 2003 03:39:50 +0100, Jim Yanik wrote:

2445/65 series were the best analog portable scope ever made.

Yup

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

 

[Jim Backus]

On Tue, 12 Aug 2003 21:55:40, Dennis <douglasfirlyx@charter.com>
rolled up his sleeves and typed:

Hi,

I have a project I'm working on, for personal use, and need some
help. I have several time-code generators(Datum) that have IRG-B
inputs, and outputs on the rear. Now they are connected via
coax output to input. I would like to get rid of the
cable and transmit the code wireless. I'm thinking
of using RF modules. It is more involved than first thought,
however. The IRG-B code is a 1000Hz carier. Any help
would be appreciated.

Mix the 1000 Hz signal with your desired RF carrier frequency and
amplify. In practice the mixer will give sum and difference frequency
outputs (plus, for the purists, a lot of other products). If your
carrier frequency is 1 MHz the output signal will consist of 999 kHz,
1000 kHz and 1001 kHz (assuming an unbalanced mixer). Separating these
signals would require a filter but is not really practical without
using a crystal filter. So the normal technique is to mix to an
intermediate frequency - perhaps 50 kHz where it is much easier to
filter out the unwanted frequency - then mix again to your final
output frequency.

The above is the old way of doing this - there are modern techniques
that achieve the same using I & Q signals through an A to D.

HTH - but I suspect the answer will be not much!

--
Jim Backus OS/2 user
bona fide replies to jimb-thecirclethingy-jita-dp-demon-dp-co-dp-uk
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