Date   

Re: Tek 7000 Series deflection plate precision?

iglesia_cristiana_arpas_eternas
 

Hi Damian,Here my two cent about:
You need to put an extra objective lens "magnetical prefereble" in order to obtain a very small dot at least half what minimum size yo like to see.and ..or.. increase the tube length, for the same reason.

Most people use a Cristal plate with phosphor where the second emission electron emitted from the target impact and release a photon ,which in turn will be detected by the photomultiplier itself, I believe that such optical conversion is not necessary , just remove the cap on photomultiplier and allow the electron hit the dinodes directly ,If this approach work, surely will be give you a enormous gain and increase in S/N ratio, which in turn allow to use less beam intensity with all benefits.obviously all in high vacuum, inside the chamber.
End of my two cent.
Gabriel.

--- In TekScopes@yahoogroups.com, "cheater00 ." <cheater00@...> wrote:

Hi guys,
could someone chime in on how precise the deflection in a Tek 7000 can be?

I'm very new to vacuum tubes and the idea of electrostatic deflection,
so please bear with any stupid questions...

My main consideration is: with modifications, would it be suitable to
jury rig an SEM (Scanning Electron Microscope)?

I am trying to do something inspired by Ben Krasnow's SEM design. If
you don't know it, he has some info here on how he made an SEM
himself:

http://benkrasnow.blogspot.de/2011/03/diy-scanning-electron-microscope.html
http://benkrasnow.blogspot.de/2011/03/diy-scanning-electron-microscope_26.html

He made the raster generator and deflection assembly and amplifiers
himself. It was my idea to use a broken 7000 series tube and hook it
up to a working 7000 scope configured with two time bases in a raster
generator setup. Of course I'd need a Tungsten filament, the one in
the 7000 CRT would be broken by having been exposed to air.

What happens in an SEM is that the electron beam *scans* a rectangular
area on the thing you're zooming in on. It moves in a raster image,
just like on a TV, or an oscilloscope in raster config. This rectangle
has to be very small, let's say 2mm across. You'd start out with a
fairly big rectangle, say 2x2 cm, to see the overall shape of the
object, then you zoom in a bit so that the rectangle is 1x1cm and pan
a little, then zoom and pan again, and so on. Think CSI: Miami
("enhance"). You might end up with a square of 2mm or even smaller.


Here's my question: the deflection needs to be precise, so e.g. if
you're horizontally 5% of the way, it still needs to be this far
across, and not erratically in some other place.

It would be bad if it e.g. jumped from 0% to 10% to 20% and so on to
100% while skipping the intermediates.

It would also be bad if it e.g. centered around that 5%, but noise and
interference meant the beam would randomly err between 1% and 9% with
5% at its center.

The rectangle as a whole needs to be moved at least in this area of
1cm or 2cm as well. It would be fairly bad if the rectangle as a whole
drifted or if the position were shaky.

How would one modify the deflection circuitry and assembly in a Tek
7000 to achieve such a small scan area? Is the circuitry going to be
low-noise and/or linear enough so that deflection precision is
retained?

How *wide* across can the electron beam be?

Thanks,
Damian


Re: Tek 7000 Series deflection plate precision?

Don Black <donald_black@...>
 

Maybe an image orthicon rather than a vidicon? They have an electron multiplier as part of the tube. I think you might find one to try but I hope there aren't too many IOs destroyed for the project.

Don Black.

On 21-May-13 12:13 AM, cleyson@... wrote:
 

I think one of the biggest problems you're going to have is
focusing the beam down small enogh to make it usable. If you're
going to use a CRT electron gun you would be better off using
magnetic focus and possibly deflection.

It might be worth trying an old one inch diameter Vidicon
camera tube if you can find one. Better still try to get
hold of a complete camera, that way you get the deflection
coil drive electronics as well. In addition, it might be easier
taking the faceplate of the front of a camera tube rather than
taking a gun assembly out of a CRT.

BTW it was Brad's idea of a custom design CRT that made me
think of the Vidicon.

Chris

--- In TekScopes@..., "cheater00 ." wrote:
>
> Brad,
> you need a way to put a photomultiplier in there somewhere. Won't do a
> lot of good otherwise.
>
> Have a look at Ben Krasnow's links, he has a very down to earth
> explanation of what's what.
>
> At his BOM, which is around the $1000 mark, a school can already
> afford one of those if it is so inclined.
>
> Cheers,
> D.
>
> On Mon, May 20, 2013 at 3:14 PM, Brad Thompson wrote:
> > On 5/20/2013 8:32 AM, cheater00 . wrote:
> >> Hi guys,
> >> could someone chime in on how precise the deflection in a Tek 7000 can be?
> >>
> >> I'm very new to vacuum tubes and the idea of electrostatic deflection,
> >> so please bear with any stupid questions...
> >>
> >> My main consideration is: with modifications, would it be suitable to
> >> jury rig an SEM (Scanning Electron Microscope)?
> >>
> >> I am trying to do something inspired by Ben Krasnow's SEM design. If
> >> you don't know it, he has some info here on how he made an SEM
> >> himself:
> >>
> >> http://benkrasnow.blogspot.de/2011/03/diy-scanning-electron-microscope.html
> >> http://benkrasnow.blogspot.de/2011/03/diy-scanning-electron-microscope_26.html
> >
> >
> >
> > Hello--
> >
> > A concept that I've kicked around for a while comprises a scanning
> > electron microscope that would be inexpensive enough to offer
> > high-school science departments. Please understand that I'm
> > not familiar with electron microscope technology and the
> > concept may be technically impractical, financially unsupportable
> > or otherwise hopelessly flawed.
> >
> > Imagine a custom-designed "cathode ray" tube that has a fixed
> > target located in place of the phosphor screen. Make the target
> > "interesting"-- e.g., a well-used coin with a small smear of
> > bacteria on the surface (metallized). The tube would include an
> > oscilloscope-tube-like electron gun and electrostatic-deflection
> > plates and a collection means for electrons deflected by the
> > target.
> >
> > Use an oscilloscope or dedicated interface box to provide
> > controllable beam deflection, amplification of the scattered
> > electrons, and display of the recovered image. Further signal
> > processing by a PC might be needed.
> >
> > My hunch is that the specialized specimen-containing tubes could be
> > mass produced at relatively low cost, since the target is not
> > replaceable and thus eliminates the need for vacuum apparatus.
> >
> > In the lab, students could explore the coin's surface and study
> > the effects of varying deflection voltages, etc.
> >
> > Comments welcomed.
> >
> > 73--
> >
> > Brad AA1IP
> >
> >
> >
> >
> > ------------------------------------
> >
> > Yahoo! Groups Links
> >
> >
> >
>



Re: 434 Storage Scope triggering problem

teamlarryohio
 

"Ed Breya" <edbreya@yahoo.com> wrote:
BTW, I think the 434 is one of the nicest scopes ever made. I don't
have one, nor have I seen or used one since over thirty years ago - it
made a great and lasting first impression on me.
One thing the 432 / 434 brought was an early SMPS predating the
custom Tek-made control IC. Properly adjusted, the 434 was a
very nice bistable storage scope.
-ls-


Re: Tek 7000 Series deflection plate precision?

Carlos
 


Hello--

A concept that I've kicked around for a while comprises a scanning
electron microscope that would be inexpensive enough to offer
high-school science departments. Please understand that I'm
not familiar with electron microscope technology and the
concept may be technically impractical, financially unsupportable
or otherwise hopelessly flawed<g>.



Comments welcomed.

73--

Brad AA1IP
Brad:

I'm not familiar with electron microscopes, but I remembered having read many years ago an article about an electron microscope built by students. It was featured in the 'Amateur Scientist' section of Scientific American magazine (when it was an excellent publication).

I just found the article here:

http://jesseenterprises.net/amsci/1973/09/1973-09-fs.html

Maybe this could be of some interest for you.


(By the way, I found also a source for the book 'The Scientific American book for the Amateur Scientist' by Clair L. Stong, published in 1960. 605 pages of very interesting material, in my opinion:

http://www.sciencemadness.org/library/books/projects_for_the_amateur_scientist.pdf

Just in case someone is interested)


Regards,

Carlos


Re: 434 Storage Scope triggering problem

Ed Breya
 

I'd guess that the guts are OK, but you have a switch or pot (including tweaks) that has contact problems. If you exercise and sufficiently jiggle all of the controls a few dozen times, it may start acting more normal - or not.

You seem to know what you're doing, so you know you can figure it out if you have the right info - instruction manual, etc, and you can access the points to make the right measurements. I think your results with going around the normal TD bias are key to understanding what's going on. Yes, the TDs and associated passive components can drift out of spec, but I'd look at the electromechanical stuff first.

BTW, I think the 434 is one of the nicest scopes ever made. I don't have one, nor have I seen or used one since over thirty years ago - it made a great and lasting first impression on me.

Ed

--- In TekScopes@yahoogroups.com, "cybertheque_museum" <msg.together@...> wrote:

Advice sought regarding the following failure on a 434 storage scope and also a question about the power supply:

1. Scope would not sweep regardless of trigger source, level, polarity; single sweep inoperative (and lamp would not light) and auto mode also would not produce a trace.

Waveform tracing up to Q645 base was ok (as per manual)

-- tested tunnel diodes CR644 and CR675 on curve tracer(both good)

-- tested Q645 on curve tracer - displayed parasitic oscillations
but IsubC - VsubC curve family was in spec, however base lead
broke off so replaced with a BC557B

-- adjusted +15 volt supply (was +15.11 V)

-- verified that ripple on all supply rails is in spec

-- verified high voltages (above +15) are in spec

At this point, in AUTO or NORM mode could get a single or few sweeps by switching the slope switch back and forth when the level control was adjusted to produce correct waveform on TP640 (as per manual). Verified that AUTO mode monostable was working properly (AUTO mode same as NORM however - no AUTO).

Discovered that by injecting a current of about 730 uA into TP678 a stable display with proper triggering can be obtained (used a 100 ohm resistor to a bench supply) - slope switch works as intended.

-- with kludge, verified all sweep rates work and are linear

-- verified triggering works at 1/3 division (has some instability)

-- single sweep runs continuously (no difference to NORM except lamp
lights or flickers with sweep rates)

-- AUTO mode same as NORM (no auto).

Interior of scope is very clean, no burnt smells or visible discolorations, no brittle insulation, etc.

Injecting current into the TD moves its operating point enough to permit trigger to begin and end the sweep but the auto mode and single sweep depend on a reset current which could be still out of range. There are a number of connections to '+5 V' in these circuits but the voltage measures at +5.14 V (I have been unable to locate the source of +5 V in the diagrams).

How likely is component aging out of specs in this scope (especially resistors)? This scope was working well, including all of the storage controls, until it abruptly had this failure when powered up two years ago. So far I have not found any 'dead' semiconductors. Within the tolerances specified, the measured voltages at test points and marked points on the schematic are in range for the specified operating conditions, as are the waveforms.

2. Where is the source of +5 VDC? (manual does not say and I looked carefully over each schematic but failed to find it).

Thanks,

Michael


434 Storage Scope triggering problem

cybertheque_museum
 

Advice sought regarding the following failure on a 434 storage scope and also a question about the power supply:

1. Scope would not sweep regardless of trigger source, level, polarity; single sweep inoperative (and lamp would not light) and auto mode also would not produce a trace.

Waveform tracing up to Q645 base was ok (as per manual)

-- tested tunnel diodes CR644 and CR675 on curve tracer(both good)

-- tested Q645 on curve tracer - displayed parasitic oscillations
but IsubC - VsubC curve family was in spec, however base lead
broke off so replaced with a BC557B

-- adjusted +15 volt supply (was +15.11 V)

-- verified that ripple on all supply rails is in spec

-- verified high voltages (above +15) are in spec

At this point, in AUTO or NORM mode could get a single or few sweeps by switching the slope switch back and forth when the level control was adjusted to produce correct waveform on TP640 (as per manual). Verified that AUTO mode monostable was working properly (AUTO mode same as NORM however - no AUTO).

Discovered that by injecting a current of about 730 uA into TP678 a stable display with proper triggering can be obtained (used a 100 ohm resistor to a bench supply) - slope switch works as intended.

-- with kludge, verified all sweep rates work and are linear

-- verified triggering works at 1/3 division (has some instability)

-- single sweep runs continuously (no difference to NORM except lamp
lights or flickers with sweep rates)

-- AUTO mode same as NORM (no auto).

Interior of scope is very clean, no burnt smells or visible discolorations, no brittle insulation, etc.

Injecting current into the TD moves its operating point enough to permit trigger to begin and end the sweep but the auto mode and single sweep depend on a reset current which could be still out of range. There are a number of connections to '+5 V' in these circuits but the voltage measures at +5.14 V (I have been unable to locate the source of +5 V in the diagrams).

How likely is component aging out of specs in this scope (especially resistors)? This scope was working well, including all of the storage controls, until it abruptly had this failure when powered up two years ago. So far I have not found any 'dead' semiconductors. Within the tolerances specified, the measured voltages at test points and marked points on the schematic are in range for the specified operating conditions, as are the waveforms.

2. Where is the source of +5 VDC? (manual does not say and I looked carefully over each schematic but failed to find it).

Thanks,

Michael


Re: 1N3718 tunnel diode testing (475 scope trigger TD)

cybertheque_museum
 

Using a B&K 501 curve tracer instead of a breadboard kludge, I can verify that all four TDs display good characteristic curves and the funky shift of the negative resistance region I had previously observed is absent.

I am taking a break from work on the 475 in order to repair a triggering problem on a 434 since I need a better scope on the bench than the Ballentine 1032A for working the the 475.


Tektronix 502 available in Ottawa

r_corriveau
 

Someone contacted me to see if I was interested in a Tektronix 502. It is located in Ottawa, Canada. If anyone local is interested please contact me and I will foward the message to him.

Robert


7854 parts 'scope on eBay

Dave Daniel
 

I found this while perusing eBay - Looks like a(n) (currently) affordable parts mule.

I know there were several people looking for 7854 parts a while back ...

DaveD


FIXED: TDS544A error "acqdataconf"

Andy
 

It was U217, one of the SRAMs for channel 3. I found the problem by replacing one SRAM, and then reinstalling the one I just replaced in the next location, and repeating until the error went away. I hit it on the third try, and only needed one replacement chip.

Andy

--- In TekScopes@yahoogroups.com, "baltimora86" <acuffe@...> wrote:

Can anyone give me any hints about what the following error on a TDS544A means?

acqdataconf.** addr = 0x738000e exp data = 0x8000 actual = 0x8002

The scope was recapped several years ago. They did a very good job, and there isn't a trace of corrosion, or leftover electrolyte on the boards. Someone also replaced U300 (one of the ADG219C memory controllers). I would guess it's the one for channel 2 based on its location.

At the moment, it powers up, but fails the acquisition, and acq/proc interface tests. I can't find any obvious functional problems with any channel, even at fast sweep rates and long record lengths. I've confirmed that the acquisition board is at fault by temporarily swapping in a known good acquisition board.

I've read that address 0x738000 corresponds to channel 3. Could the error indicate a bad SRAM chip?

Thanks in advance,

Andy


Re: Tek 575 tube adapter

lindberg.adam
 

I usually use a 1kohm resistor connected between the base and emitter connection, doing so converts the current markings to voltage markings in the step generator.

so 1mA = 1V and 0,5mA = 0,5V and so on

this is also handy when measuring mosfets

I built a small rigg with different tube bases and banana jacks to patch the heater and external g2 source if needed then you can just connect the rigg to the curve tracer.


Re: Repair question for Type D High-Gain Differential plug-in

Michael A. Terrell
 

I once had the joy of having to find 16 matched 6146 out of 150 tubes. This was for a video modulator, where they were run in parallel to get the required power and a low output impedance. I managed two almost matched sets, but they aged rapidly in use. Wasn't '50's brute force technology interesting? ;-)

-----Original Message-----
From: "tubesnthings@aol.com" <tubesnthings@aol.com>
Sent: May 20, 2013 3:26 PM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] Repair question for Type D High-Gain Differential plug-in

Dan;
Tube tolerances vary greatly but in a few cases I have seen remarkable consistency.
Strangely, one example is a certain NOS 12AT7WA - 10-out-of-ten (20 triodes!) showed perfectly matched transconductance readings, exactly centered between min/max specs!!

I just picked up a stash of tubes which should contain at least a few 5879s but I haven't gotten around to sorting…

Tek matched tubes for current in test fixtures which resembled the circuit conditions the tube was designated for.
Michael A. Terrell


U400 (155-0236-00) Channel Switch replacement

thomas.lafay
 

Greetings. I have a replacement for the U400 in development, revision B, that is near finished in layout amd am wondering if there's any interest in this project. It would be nice to have others review the schematic before layout is completed. Send me an email at my yahoo address and I'll forward a copy of the schematic to you. Tom


Re: Repair question for Type D High-Gain Differential plug-in

tubesnthings@aol.com <tubesnthings@...>
 

Dan;
Tube tolerances vary greatly but in a few cases I have seen remarkable consistency.
Strangely, one example is a certain NOS 12AT7WA - 10-out-of-ten (20 triodes!) showed perfectly matched transconductance readings, exactly centered between min/max specs!!

I just picked up a stash of tubes which should contain at least a few 5879s but I haven't gotten around to sorting…

Tek matched tubes for current in test fixtures which resembled the circuit conditions the tube was designated for.

Bernd

Sent from my Verizon Wireless Droid


-----Original message-----
From: Daniel Koller <kaboomdk@...>
To:
"TekScopes@..." <TekScopes@...>
Sent:
Mon, May 20, 2013 14:39:47 GMT+00:00
Subject:
Re: [TekScopes] Repair question for Type D High-Gain Differential plug-in

 

Howdy Bernd,

   I've tried swapping tubes.  It's hard to do in this case since it requires both the plate balance and vertical controls to be moved to near opposite ends of their ranges.  I am too far out of balance.

   Unfortunately, to buy a pair of matching tubes, I can only go by what is offered - i.e. what is commonly measured.  Given that most people on e-bay seem to report only Gm (if that), can I use it as a rough guide to "match" the tubes?   If I buy a pair of tubes from identical manufacturer, presumably new, with the same Gm, are they likely to have the same plate resistance and gain characteristics?   Unfortunately, I think this is the only choice I have - buy a bunch of tubes, and match them myself, in-circuit.  

   My question then is one of manufacturing.   How far off were the tube parameters, say from GE or RCA, from tube to tube?  1%?  10%, 50%??

  Thanks,

  Dan



From: "tubesnthings@..." <tubesnthings@...>
To: TekScopes@...
Sent: Saturday, May 18, 2013 1:32 PM
Subject: Re: [TekScopes] Repair question for Type D High-Gain Differential plug-in

 
Dan,
I have not worked on my type D units, so without looking at the circuit but in general;
Differential amps do rely on closely matched sections. The matching criterium is not transconductance of the tubes as seen by a tube tester, but plate or cathode current in the plug-in's circuit(s). An easy way to determine the tubes' contribution to amp imbalance is to swap them with each other; if the imbalance "follows" the tubes you've isolated that problem. I suspect you'll need to shop for tubes…

Good luck.
Bernd Schroder

Sent from my Verizon Wireless Droid


-----Original message-----
From: Daniel Koller <kaboomdk@...>
To:
"TekScopes@..." <TekScopes@...>
Sent:
Sat, May 18, 2013 13:00:59 GMT+00:00
Subject:
[TekScopes] Repair question for Type D High-Gain Differential plug-in

 
Howdy Folks,

  I'm getting around to repairing my defective plug ins, and I have a question about the type D, for anyone who may be familiar with the circuit.  

  In the output circuit, there is a pair of type 5879 tubes, V3704 and V3604, that are a matched pair.  How close in gain do they have to be to work in this circuit?

  I have three tubes, measured on my Hickok tester as follows:

     V3604 1210 u-Mhos
     V3704  560 u-Mhos
     Spare   975 u-Mhos

  The tube tester specs give 630 u-Mhos as the minimum transconductance for a good tube so V3704 was replaced with the spare.  But I still can't balance the 
amplifier at the most sensitive settings with the grids of the tubes shorted together, as described in the service instructions.  I presume that is because the gains are
so off.  Is this so, or could it be something else?  Is transconductance at a fixed bias enough info to get me a reasonably close pair of tubes without a curve tracer?

  Thanks for the advice.

  Dan




Re: TEK 453 Vert Amp - not 453A

Michael A. Terrell
 

It's been so long since I've used a paper Tektronix manual that I'd forgotten all about their scheme to prevent making useful photocopies. The advent of color copiers made them worthless. Reminds me of the trick being used in the classic Sci-Fi book, "When Worlds Collide" .:)

-----Original Message-----
From: Tom Miller <tmiller11147@verizon.net>
Sent: May 20, 2013 1:17 PM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] TEK 453 Vert Amp - not 453A

Most likely is the copy he is using is one of the monochrome scans and the blue color has been lost.
Michael A. Terrell


Re: TEK 453 Vert Amp - not 453A

 

Most likely is the copy he is using is one of the monochrome scans and the blue color has been lost.
 
Regards,
Tom
 

----- Original Message -----
From: David
Sent: Monday, May 20, 2013 12:46 PM
Subject: Re: [TekScopes] TEK 453 Vert Amp - not 453A

 

The 453A manual uses a thick light blue line for the demarcation,
solid circles for soldered connections, and arrows for mechanical
connections.

Based on the legend in the 453 manual which immediately follows the
schematic, the thin demarcation line was originally blue, solid
circuits are soldered connections, and open circles are mechanical
connections.

Maybe the 453 manual from ArtekManuals is a more faithful reproduction
then the various free ones floating around.

On Mon, 20 May 2013 12:29:46 -0400 (GMT-04:00), "Michael A. Terrell"
<mike.terrell@...> wrote:

> Mark, the black dots where the lines cross the boarder to R73, Q84 and others along that line should be open circles to signify a wire connected to something off the circuit board. Some companies assign each a terminal number to make it easier to assemble or repair the equipment. All our schematics used 'E1, E2, E3' etc. As has been pointed out, that line that appears to be shorting out everything should have been broken up dashes, but whoever scanned it either darkened the lines, or had the scanner configured wrong. The lines on the paper schematics are obviously board demarcation points.
>
>-----Original Message-----
>>From: Mark Wendt <mark.wendt@...>
>>Sent: May 20, 2013 8:42 AM
>>To: TekScopes@...
>>Subject: Re: [TekScopes] TEK 453 Vert Amp - not 453A
>>
>>Tom,
>>
>>I'm probably being really dense, but which line are you saying should be
>>dashed? I'm seeing five of those demarks around components Q84 and the
>>R75 pot that look like they are tying those circuit traces together.
>>Should those be little "hoops" that show a crossing but not connection
>>point? If so, then the ground point in this instance wouldn't make a
>>whole lot of sense showing where it is the schematic.
>>
>>On 05/20/2013 08:28 AM, Tom Miller wrote:
>>> That line should have been dashed. Print it out and trace over it with a red
>>> pencil and it will make a lot more sense.
>>>
>>> If you put the whole schematic together, you can follow the line completely
>>> around the circuit. It is there to identify all the board mounted parts.
>>>
>>> I have seen it done the same on a few other Tek manuals.
>>>
>>> Tom


Re: RM-503 Manual

Michael A. Terrell
 

bama.edebris.com/download/tek/503/503late.pdf

Not rack mount, but it is the same basic scope other than the physical layout.

-----Original Message-----
From: WalterT <sjotrollet@yahoo.com>
Sent: May 20, 2013 12:14 PM
To: TekScopes@yahoogroups.com
Subject: [TekScopes] RM-503 Manual

Anyone have any hints on where I can get a copy of the
5" scope RM-503 manual? Hopefully free because that's what
I have in the scope.
Two of them were dumped on me. I hope to fix one for #2 son
who just got his license last year (K4UDP) and the other one
is up for parts if anyone needs anything.
Tks & 73
Walt (N4GL) sjotrollet@yahoo.com

Michael A. Terrell


Re: TEK 453 Vert Amp - not 453A

John
 

WE're talking about the 453 here, and it's the same, in that the light blue line (as seen on original schematic)is a demarquation line for on/off board components.

Could the original poster please state if he has a Nuvistor or FET version? An out-of-spec nuvistor gives rise to dc's which place the trace off-screen,

John

--- In TekScopes@yahoogroups.com, David <davidwhess@...> wrote:

The 453A manual uses a thick light blue line for the demarcation,
solid circles for soldered connections, and arrows for mechanical
connections.

Based on the legend in the 453 manual which immediately follows the
schematic, the thin demarcation line was originally blue, solid
circuits are soldered connections, and open circles are mechanical
connections.

Maybe the 453 manual from ArtekManuals is a more faithful reproduction
then the various free ones floating around.

On Mon, 20 May 2013 12:29:46 -0400 (GMT-04:00), "Michael A. Terrell"
<mike.terrell@...> wrote:

Mark, the black dots where the lines cross the boarder to R73, Q84 and others along that line should be open circles to signify a wire connected to something off the circuit board. Some companies assign each a terminal number to make it easier to assemble or repair the equipment. All our schematics used 'E1, E2, E3' etc. As has been pointed out, that line that appears to be shorting out everything should have been broken up dashes, but whoever scanned it either darkened the lines, or had the scanner configured wrong. The lines on the paper schematics are obviously board demarcation points.

-----Original Message-----
From: Mark Wendt <mark.wendt@...>
Sent: May 20, 2013 8:42 AM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] TEK 453 Vert Amp - not 453A

Tom,

I'm probably being really dense, but which line are you saying should be
dashed? I'm seeing five of those demarks around components Q84 and the
R75 pot that look like they are tying those circuit traces together.
Should those be little "hoops" that show a crossing but not connection
point? If so, then the ground point in this instance wouldn't make a
whole lot of sense showing where it is the schematic.

On 05/20/2013 08:28 AM, Tom Miller wrote:
That line should have been dashed. Print it out and trace over it with a red
pencil and it will make a lot more sense.

If you put the whole schematic together, you can follow the line completely
around the circuit. It is there to identify all the board mounted parts.

I have seen it done the same on a few other Tek manuals.

Tom


Re: TEK 453 Vert Amp - not 453A

 

The 453A manual uses a thick light blue line for the demarcation,
solid circles for soldered connections, and arrows for mechanical
connections.

Based on the legend in the 453 manual which immediately follows the
schematic, the thin demarcation line was originally blue, solid
circuits are soldered connections, and open circles are mechanical
connections.

Maybe the 453 manual from ArtekManuals is a more faithful reproduction
then the various free ones floating around.

On Mon, 20 May 2013 12:29:46 -0400 (GMT-04:00), "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

Mark, the black dots where the lines cross the boarder to R73, Q84 and others along that line should be open circles to signify a wire connected to something off the circuit board. Some companies assign each a terminal number to make it easier to assemble or repair the equipment. All our schematics used 'E1, E2, E3' etc. As has been pointed out, that line that appears to be shorting out everything should have been broken up dashes, but whoever scanned it either darkened the lines, or had the scanner configured wrong. The lines on the paper schematics are obviously board demarcation points.

-----Original Message-----
From: Mark Wendt <mark.wendt@nrl.navy.mil>
Sent: May 20, 2013 8:42 AM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] TEK 453 Vert Amp - not 453A

Tom,

I'm probably being really dense, but which line are you saying should be
dashed? I'm seeing five of those demarks around components Q84 and the
R75 pot that look like they are tying those circuit traces together.
Should those be little "hoops" that show a crossing but not connection
point? If so, then the ground point in this instance wouldn't make a
whole lot of sense showing where it is the schematic.

On 05/20/2013 08:28 AM, Tom Miller wrote:
That line should have been dashed. Print it out and trace over it with a red
pencil and it will make a lot more sense.

If you put the whole schematic together, you can follow the line completely
around the circuit. It is there to identify all the board mounted parts.

I have seen it done the same on a few other Tek manuals.

Tom


Re: Tek 7000 Series deflection plate precision?

Chris Leyson
 

Hi, yes that's what I had in mind. I'm not sure how the target electrode is arranged, whether there is a metal-glass seal all the way around or whether it connects to a single wire. If there is a metal/glass seal all the way around it should be easier to remove the faceplate.

Chris

--- In TekScopes@yahoogroups.com, "cheater00 ." <cheater00@...> wrote:

Chris,
wouldn't this mean the vidicon tube gets depressurized? Do you mean I
should cut away the front of the glass envelope?

Cheers,
D.

On Mon, May 20, 2013 at 4:13 PM, <cleyson@...> wrote:
I think one of the biggest problems you're going to have is
focusing the beam down small enogh to make it usable. If you're
going to use a CRT electron gun you would be better off using
magnetic focus and possibly deflection.

It might be worth trying an old one inch diameter Vidicon
camera tube if you can find one. Better still try to get
hold of a complete camera, that way you get the deflection
coil drive electronics as well. In addition, it might be easier
taking the faceplate of the front of a camera tube rather than
taking a gun assembly out of a CRT.

BTW it was Brad's idea of a custom design CRT that made me
think of the Vidicon.

Chris

--- In TekScopes@yahoogroups.com, "cheater00 ." <cheater00@> wrote:

Brad,
you need a way to put a photomultiplier in there somewhere. Won't do a
lot of good otherwise.

Have a look at Ben Krasnow's links, he has a very down to earth
explanation of what's what.

At his BOM, which is around the $1000 mark, a school can already
afford one of those if it is so inclined.

Cheers,
D.

On Mon, May 20, 2013 at 3:14 PM, Brad Thompson <brad.thompson@> wrote:
On 5/20/2013 8:32 AM, cheater00 . wrote:
Hi guys,
could someone chime in on how precise the deflection in a Tek 7000 can be?

I'm very new to vacuum tubes and the idea of electrostatic deflection,
so please bear with any stupid questions...

My main consideration is: with modifications, would it be suitable to
jury rig an SEM (Scanning Electron Microscope)?

I am trying to do something inspired by Ben Krasnow's SEM design. If
you don't know it, he has some info here on how he made an SEM
himself:

http://benkrasnow.blogspot.de/2011/03/diy-scanning-electron-microscope.html
http://benkrasnow.blogspot.de/2011/03/diy-scanning-electron-microscope_26.html
<snip>

Hello--

A concept that I've kicked around for a while comprises a scanning
electron microscope that would be inexpensive enough to offer
high-school science departments. Please understand that I'm
not familiar with electron microscope technology and the
concept may be technically impractical, financially unsupportable
or otherwise hopelessly flawed<g>.

Imagine a custom-designed "cathode ray" tube that has a fixed
target located in place of the phosphor screen. Make the target
"interesting"-- e.g., a well-used coin with a small smear of
bacteria on the surface (metallized). The tube would include an
oscilloscope-tube-like electron gun and electrostatic-deflection
plates and a collection means for electrons deflected by the
target.

Use an oscilloscope or dedicated interface box to provide
controllable beam deflection, amplification of the scattered
electrons, and display of the recovered image. Further signal
processing by a PC might be needed.

My hunch is that the specialized specimen-containing tubes could be
mass produced at relatively low cost, since the target is not
replaceable and thus eliminates the need for vacuum apparatus.

In the lab, students could explore the coin's surface and study
the effects of varying deflection voltages, etc.

Comments welcomed.

73--

Brad AA1IP




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