Re: Tek 576 CT fiber optic readout lamps; replaced with LED's ?
Jim,
I don't know your age; but my eye doctor says that I am approaching "mild cataract" territory.
While looking at an LED clock at night, I came up with a simple test for cataracts. If I look at
the clock in total darkness, I see a halo (maybe about 5 degrees in angular width) around the numerals.
I hypothesize that this is due to scattering in my corona. I would expect this effect to be much stronger
for a blue LED display, when compared with a red display
Stephen Menasian
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FS: Tektronix TDS2014 Oscilloscope
Hello All,
I have for sale a Tektronix TDS2014 100 MHz, 4 channel, oscilloscope.? It passes all self tests and self calibration and has a good display.? There are some cracks around the edges of the case and on a corner of the front panel. The power button has been replaced with a 3D printed button.? It does not include an option module or probes.?? I cannot guarantee the calibration on this so I am selling it AS-IS.? The price is $260 plus shipping. Located in Maryland USA.
Tom Bryan
N3AJA
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Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603
Thanks Ed and Miguel for the help you are giving me.
Miguel, I'll send you more photos under the microscope today.
At the left end of the meandering resonator is a double comb which I think is a capacitor which is not on the schematic, the other end of the resonator is open.
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Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603
Hi Ed, Thanks for your explanation. it is a pleasure to read it. Photos was taken by Attilio, I only have uploaded them. I will ask to send me again more oscillator section detailed photos. Regards! -----Mensaje original----- De: [email protected] [mailto: [email protected]] En nombre de Ed Breya via groups.io Enviado el: viernes, 5 de febrero de 2021 6:57 Para: [email protected]Asunto: Re: [TekScopes] Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603 Yesterday I looked at the pictures Miguel posted, of the module innards, and I looked at the manuals for the TR501,502,and 503. They all have nearly identical circuits for operating the LO/RF module. I'm at the farm now, so don't have the info at hand, but what I recall is that this module has the same base part number, and a different dash number for each model. The other RF modules and pieces seem to be the same in all models. So, the LO/RF module is really the only difference. Looking at the LO physical circuit in the picture, it looks very close to the schematic shown in the manuals, except that the output to the coupler appears to be at one end of the meander line resonator, not tapped near the middle. I looked at Miguel's photo album today, and see there's a lot more nice and detailed pictures - nice photography work Miguel. These circuits are mostly strip-line on alumina substrates, and in what I'd call the danger zone for modification. They are big enough and visible with reasonable magnification, making it very tempting to alter with fine hand tools. It's dangerous because the bond wires and parts are very delicate, so a slip up can easily ruin it. The alumina substrates are nearly impossible to safely solder to in place, limiting the types of possible modification. The other kinds of microwave circuits like PTFE type boards with soldered on parts, and the nearly microscopic scale sapphire ones, I don't consider dangerous - the bigger, board-based stuff is pretty easy to deal with, while the extremely small stuff can't readily be worked on, so I can't and don't mess with those, so they're safe from destruction by me. If you have the right tools like wire bonding machines and such, it's a different story. Anyway, here's what I've been thinking. First, the three different LO/RF module/model types are nearly identical except for the nominal LO being 2072 MHz for the TR503, while the other two are 2095 MHz. That's about a one percent difference. Second, it could be that the the different dash numbers of the base part are almost all the same internally, with exception of the oscillator section only, being one of two different hybrid assemblies. OR, it could be that the oscillator hybrids are actually all the same, and differ only in some slight way that can be modified during assembly into the different dash versions. This would make sense, to not have to make two different complete hybrids that are so close in function, like a one percent difference in frequency. One way to do this would be to set the proper frequency during final build, by adding (like a solder gob or extra bond wires) or removing (like cutting a trim stub) something that's relatively easy to do. Since only two frequencies are involved (unless this module was used in other products too), one frequency could be "stock," and the other a simple mod. This also presume though, that these were all developed in the same time frame, with all the required application info figured out already. It is quite common to see all sorts of extra floating or detachable stubs and such in planar microwave circuits, and evidence of "fine tuning" with cuts (even laser trimming), silver dag, solder, bond wires, added foil strips etc. So, one thing I'd look for is to see if there is any evidence of trimming on the meander line resonator - either added or subtracted. The resonator changes from meandering to straight, just past the transistor hookup. Unfortunately, the open end (the only "easy" place to tweak) is hidden under a feed-through post. What I'm thinking is that if it's possible to look closely from different angles in that area, it may show some trim features right at the end. For instance, let's say that the "stock" version is 2072 MHz. There would then be a feature where a tiny stub at the end could be cut loose, shortening the line by a certain amount, to run at 2095 MHz. If it were the other way around, then there would be an additive feature to lengthen it and go from 2095 to 2072, like a bunch of bond wires, solder, or Ag dag jumping the line end to a floating stub. Again, this is all based on my "one oscillator hybrid type" hypothesis, which could be entirely wrong, but I think it's worth a close look at that end, if possible. So Miguel, I assume you have the actual module shown in the pictures. Is it possible to take a very close look at that line end, and report on it? I have some other ideas that I'll put up tomorrow. Ed Scanned by McAfee and confirmed virus-free. Find out more here:
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Re: Cleaning 576 display selector switches
From the 7400 series ICs there are date codes of 7949 and 8009 so maybe 1980-1981?
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Re: The reason for Tek delay lines
Ebay is just way to much pain for way too little gain these days. The reason that you use ebay for "inventory reduction" is that assures you that your useful stuff is going to a ‘good home’. If you just give it away there is a very good chance that it will end up in the bin as UKers are likely to say. The price tells us what others value our treasure at. One of the best features of ebay is that you don't have to price your stuff, the market will do it for you. Just my experience. Eric WB6KCN -----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Jim Ford Sent: Thursday, February 4, 2021 8:48 PM To: [email protected]Subject: Re: [TekScopes] The reason for Tek delay lines Well, Bert, I just this week sent my wife an email with [email protected] and [email protected] and my test equipment inventory list in it. In case of my demise, I've instructed her to post to both groups and ask for people to come buy my stuff. I trust you guys (and gals) in advance to give my widow a reasonable price. It was actually really simple and easy, and now my mind is at ease about my stuff when I'm gone. I encourage others to do the same. Jim Ford ------ Original Message ------ From: "Bert Haskins" <bhaskins@...> To: [email protected]Sent: 2/4/2021 7:35:26 AM Subject: Re: [TekScopes] The reason for Tek delay lines On 2/4/2021 12:05 AM, Ed Breya via groups.io wrote: Magnetostrictive delay lines are suitable for low speed AC signals, providing acoustic delay - they were good for early computer equivalent of DRAM (with re-circulation), before practical large solid state memory arose, but not for scopes.
Ed
Yep, and I still have at least one of those on one of my far back shelves along most of the old processors, 2102 and ttl memory and such. The delay line was at the very heart of a Westinghouse NC controller. Hard to believe but some of that stuff is still out there running on industrial controllers. Someday all of thiswill just go out to a recycler along with my machine shop stuff. Ebay is just way to much pain for way too little gain these days. Bert
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Re: Tek 576 - step generator power amp - how to check?
Hi Ozan, thanks a lot for all these insights - it helps clearing up the fog in my head. I admire how you get all these numbers by looking at the schematic alone. I think I understood the current computations as a function of AD voltage - it depends on the number of PN sections on the currents way to ground, I guess. But I didn't manage to see how you can predict the voltage range of +3.4V / -2.7V at AD point. The preceding transistor is hanging between -75 and +12 volts... That said, I did make the current measurements on what I call the "power amp" alone, and it corresponds quite well with your predictions: - all the resistor in series are approx. 65 Ohms + 2V at AD -> 12,7 mA (9,2 mA computed)
+ 3V at AD -> 26,8 mA (24,6 mA computed)
-1,3V at AD -> 10,5 mA
- 2,3V at AD -> 25,3 mA Its not perfectly symmetrical, but thats seems normal given the design so I decided not to touch anything on this power amp and put the step generator back. Thats not an easy task, with all the dangling wires around and one must take care not to mix up the connectors. Thats where I am right now, fingers crossed, I will make more measurements on the step generator amp itself as you suggested. I intend to post some pictures of the 576 with the step generator card removed. Haven't found any on the web so far. Looks a bit messy compared to the rest of the unit. so far, cheers Martin
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Re: Spectrum analyzer Tektronix 7L13 on mainframe Tektronix 7603
Yesterday I looked at the pictures Miguel posted, of the module innards, and I looked at the manuals for the TR501,502,and 503. They all have nearly identical circuits for operating the LO/RF module. I'm at the farm now, so don't have the info at hand, but what I recall is that this module has the same base part number, and a different dash number for each model. The other RF modules and pieces seem to be the same in all models. So, the LO/RF module is really the only difference.
Looking at the LO physical circuit in the picture, it looks very close to the schematic shown in the manuals, except that the output to the coupler appears to be at one end of the meander line resonator, not tapped near the middle. I looked at Miguel's photo album today, and see there's a lot more nice and detailed pictures - nice photography work Miguel.
These circuits are mostly strip-line on alumina substrates, and in what I'd call the danger zone for modification. They are big enough and visible with reasonable magnification, making it very tempting to alter with fine hand tools. It's dangerous because the bond wires and parts are very delicate, so a slip up can easily ruin it. The alumina substrates are nearly impossible to safely solder to in place, limiting the types of possible modification. The other kinds of microwave circuits like PTFE type boards with soldered on parts, and the nearly microscopic scale sapphire ones, I don't consider dangerous - the bigger, board-based stuff is pretty easy to deal with, while the extremely small stuff can't readily be worked on, so I can't and don't mess with those, so they're safe from destruction by me. If you have the right tools like wire bonding machines and such, it's a different story.
Anyway, here's what I've been thinking. First, the three different LO/RF module/model types are nearly identical except for the nominal LO being 2072 MHz for the TR503, while the other two are 2095 MHz. That's about a one percent difference. Second, it could be that the the different dash numbers of the base part are almost all the same internally, with exception of the oscillator section only, being one of two different hybrid assemblies. OR, it could be that the oscillator hybrids are actually all the same, and differ only in some slight way that can be modified during assembly into the different dash versions. This would make sense, to not have to make two different complete hybrids that are so close in function, like a one percent difference in frequency. One way to do this would be to set the proper frequency during final build, by adding (like a solder gob or extra bond wires) or removing (like cutting a trim stub) something that's relatively easy to do. Since only two frequencies are involved (unless this module was used in other products too), one frequency could be "stock," and the other a simple mod. This also presume though, that these were all developed in the same time frame, with all the required application info figured out already.
It is quite common to see all sorts of extra floating or detachable stubs and such in planar microwave circuits, and evidence of "fine tuning" with cuts (even laser trimming), silver dag, solder, bond wires, added foil strips etc. So, one thing I'd look for is to see if there is any evidence of trimming on the meander line resonator - either added or subtracted. The resonator changes from meandering to straight, just past the transistor hookup. Unfortunately, the open end (the only "easy" place to tweak) is hidden under a feed-through post. What I'm thinking is that if it's possible to look closely from different angles in that area, it may show some trim features right at the end. For instance, let's say that the "stock" version is 2072 MHz. There would then be a feature where a tiny stub at the end could be cut loose, shortening the line by a certain amount, to run at 2095 MHz. If it were the other way around, then there would be an additive feature to lengthen it and go from 2095 to 2072, like a bunch of bond wires, solder, or Ag dag jumping the line end to a floating stub. Again, this is all based on my "one oscillator hybrid type" hypothesis, which could be entirely wrong, but I think it's worth a close look at that end, if possible.
So Miguel, I assume you have the actual module shown in the pictures. Is it possible to take a very close look at that line end, and report on it?
I have some other ideas that I'll put up tomorrow.
Ed
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Re: 2232 2221A eprom images or current Gtek , DataIO software.
The site ko4bb.com maintains an extensive library of EPROM image files,
among other things. I would strongly suggest looking to see what's
there, and contributing things they don't have.
Thanks!
toggle quoted message
Show quoted text
On 01-Feb-21 11:48, Bert Haskins wrote: The
"Re: [TekScopes] NEW TOPIC: Outstanding Rockland Instruments 7000
Plugin; WAS: Slightly OT- Wavetek 7530B?"
post got me thinking about? "rom rot" and wondering if anyone has
archived the eprom images of the 2232, 2221A Tek scopes.
If the answer is no, maybe I should make a project out of doing a
resurrection on one or more of my old eprom programmers and doing the deed.
I have a Gtek 7128 and a Data I/O 201 and a few computers that will do
RS-232.
I also have a pretty good inventory of eproms.
If anyone else is interested in this, just rattle my cage.
? Bert
--
---
Bruce Lane, ARS KC7GR
kyrrin (at) bluefeathertech dot com
"Quando Omni Flunkus Moritati" (Red Green)
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Re: Slightly OT: OK Electronics tinyscope --Little CRTs Overview
Thanks for the Turtles quote, Tom. It reminds me of another Tom at a previous employer who liked to quote it.
Jim Ford
toggle quoted message
Show quoted text
------ Original Message ------ From: "Tom Lee" <tomlee@...> To: [email protected]Sent: 2/4/2021 1:35:57 PM Subject: Re: [TekScopes] Slightly OT: OK Electronics tinyscope --Little CRTs Overview “Turtles all the way down”
Sent from my iThing, so please forgive brevity and typos
On Feb 4, 2021, at 13:34, snapdiode via groups.io <snapdiode@...> wrote:
LOL you could build one of these CRTs into the trigger level knob of eg a 547....
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Re: The reason for Tek delay lines
Well, Bert, I just this week sent my wife an email with [email protected] and [email protected] and my test equipment inventory list in it. In case of my demise, I've instructed her to post to both groups and ask for people to come buy my stuff. I trust you guys (and gals) in advance to give my widow a reasonable price. It was actually really simple and easy, and now my mind is at ease about my stuff when I'm gone. I encourage others to do the same. Jim Ford
------ Original Message ------ From: "Bert Haskins" <bhaskins@...> To: [email protected]Sent: 2/4/2021 7:35:26 AM Subject: Re: [TekScopes] The reason for Tek delay lines
On 2/4/2021 12:05 AM, Ed Breya via groups.io wrote:
Magnetostrictive delay lines are suitable for low speed AC signals, providing acoustic delay - they were good for early computer equivalent of DRAM (with re-circulation), before practical large solid state memory arose, but not for scopes.
Ed Yep, and I still have at least one of those on one of my far back shelves along most of the old processors, 2102 and ttl memory and such.
The delay line was at the very heart of a Westinghouse NC controller.
Hard to believe but some of that stuff is still out there running on industrial controllers.
Someday all of thiswill just go out to a recycler along with my machine shop stuff.
Ebay is just way to much pain for way too little gain these days.
Bert
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Re: Tek 576 CT fiber optic readout lamps; replaced with LED's ?
Yeah, I find I can't read blue lit signs at night, while red is sharp and clear. Short wavelengths are a blur, but long wavelengths are fine. Don't make blue signs, folks; we can't read 'em.
Jim Ford
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Show quoted text
------ Original Message ------ From: "Eric" <ericsp@...> To: [email protected]Sent: 2/4/2021 7:14:58 AM Subject: Re: [TekScopes] Tek 576 CT fiber optic readout lamps; replaced with LED's ? In terms of sensitivity human eye tends towards the green while the electronic eye tends towards the blue. Hence the blue phosphor for camera displays my camera can see the screen clear as day where as the poor human cant see anything. One of my personal issues with lighting I believe seems to stem from my astigmatism. It seems to present its self the worst trying to read backlit gas station signs at night and blue LED’s. I also think this has to do with the wavelength of the blue LEDS that dominate the devices. There is a Cyan LED that I find quite pleasing and acceptable where as the standard “blue” I have named eye searingly blue. But the cyan and nice blue colors are very hard to come by and not made in large lots. I can still order the cyan part number but I have to in lots of 20,000.
In terms of the graticule lights I have done and LED mod to a few 7000 series scopes.
On a 7854 soft white for all the control lamps with a SMD current limiting resister on the collector of the driver transistors worked really well and was clean. I might even be able to dig up the part number for soft whites.
On a 7704A and a few 7603’s I have found a high brightness cool white LED does a good job. If there is interest I can post some pictures with Clear, Tek blue, and ND filters when I am back in the lab tonight.
Eric
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of 搁别苍é别
Sent: Wednesday, February 3, 2021 4:31 PM
To: [email protected]
Subject: Re: [TekScopes] Tek 576 CT fiber optic readout lamps; replaced with LED's ?
I am pleased to know that I am not the only one who finds Blue LEDs irritating...I took all of them out of the display in the VW dash and replaced them with red....seem to do this on all equipment too...red or green...even yellow...works well as a replacements for incandescent bulbs on my 475.
Thanks for the tip on Photo issue.
搁别苍é别
On 2/3/21 12:25 PM, Ed Breya via groups.io wrote:
Eric mentioned the awfulness of blue LEDs in some applications, and I agree. The blue color looks very cool at first, but becomes irritating after a while. I remember in my HP8568 tracking generator project I built a multi-color indicator to show different functions, with a red and a blue LED glued inside an old style pilot light with a white opaque jewel for diffusion. It wasn't long before I got so sick of it that I tore it apart and remade it with red and green. The green turned out be a very close match (visually) to the P31 phosphor in the display, and is very pleasing. I also dislike the P11 phosphor in some of my scopes - I'd trade for green any day.
A while back, I did some experiments with replacing the graticule illumination lamps in a 7K mainframe (maybe those are #349?) with "white" LEDs. It looked good, visually, pretty much the same as incandescent. Then I tried taking some screen shots with a phone camera. The graticule was barely visible even at maximum brightness. The LED "white" spectrum did not align well with the camera's response, even though it appeared OK to the eye. So, if anyone is contemplating changing bulbs to LEDs, consider the photographic consequences, and do some experiments with different LEDs (and maybe cameras too) before committing. This was a while ago, using some LEDs I had on hand. Different or newer, better ones may work fine. I'd like to eventually figure out good LED replacements for all graticule lamps, and the 576 readout, where screen shots are often needed.
Ed
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Re: Slightly OT: OK Electronics tinyscope --Little CRTs Overview
3DPx? I had one, it was used to extend the the baseline of a radar trace.? The normal scan line was made to be a circle, and the center electrode was used to deflect a radar signal outwards.
I put one in an oscilloscope I made from the schematics included in the heathkit catalog (magnifying glass anyone?).
Made it on a breadpan and piped in the power supply voltages. Octal tube base from a dead tube used as a power supply plug. Needed to be careful, but it worked.
Harvey
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Show quoted text
On 2/4/2021 8:58 PM, Leon Robinson wrote: Many years ago I had a 3" CRT P1 phosphor & 5 deflection electrodes. ?2 for X & 2 for Y & 1 for radial deflection it came out of the face of the tube. ?I don't remember the number
Leon Robinson ?K5JLR
-------- Original message --------
From: Brad Thompson <brad.thompsonaa1ip@...>
Date: 02/04/2021 4:12 PM (GMT-06:00)
To: [email protected]
Subject: Re: [TekScopes] Slightly OT: OK Electronics tinyscope --Little CRTs Overview
Tom Lee wrote on 2/4/2021 4:35 PM:
“Turtles all the way down”
Hello--
Keep a lookout for a type 913 CRT. From a distance, it resembles a
metal-envelope 6L6,
but there's a one-inch diameter phosphor screen in the top end. Go here
and scroll down almost all of the way
for more info:
73--
Brad? AA1IP
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Re: Slightly OT: OK Electronics tinyscope --Little CRTs Overview
Many years ago I had a 3" CRT P1 phosphor & 5 deflection electrodes. ?2 for X & 2 for Y & 1 for radial deflection it came out of the face of the tube. ?I don't remember the number
Leon Robinson ?K5JLR
toggle quoted message
Show quoted text
-------- Original message -------- From: Brad Thompson <brad.thompsonaa1ip@...> Date: 02/04/2021 4:12 PM (GMT-06:00) To: [email protected] Subject: Re: [TekScopes] Slightly OT: OK Electronics tinyscope --Little CRTs Overview Tom Lee wrote on 2/4/2021 4:35 PM: “Turtles all the way down”
Hello-- Keep a lookout for a type 913 CRT. From a distance, it resembles a metal-envelope 6L6, but there's a one-inch diameter phosphor screen in the top end. Go here and scroll down almost all of the way for more info: 73-- Brad? AA1IP
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Re: Tek 4041 GPIB Controller
Monty: I have 512K of RAM and all of the ROMs originally offered. Let me
know when you have anything new to offer.
Gary
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Show quoted text
On Thu, Feb 4, 2021, 16:10 Monty McGraw <mmcgraw74@...> wrote: I completed my port of the classic Adventure game to the Tektronix 4041!
All the files have been uploaded to my 4041 program repository in the
Games/Adventure folder:
[Adventure Folder](
)
I started with my Adventure port to the 4052/4054 computers - a lot of
4041 BASIC commands are the same, the work was around the differences :)
This program should run on any 4041 with a working tape or DDU floppy or
hard disk.
The screenshot link below was from using Tera Term on my Windows 10 laptop:
[Adventure on Tektronix 4041](
)
I will now work on removing the dependency for the tape/floppy/hard disk
since the minimum memory of the 4041 is 128KB, I may be able to combine all
the files into the main program.
You will still need the Program Development Option ROM as the program
files are ASCII text and have to be parsed by the Program Development ROMs.
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Re: Cleaning 576 display selector switches
Keith,
Just out of curiosity, do you know when your 576 was made?
toggle quoted message
Show quoted text
On Thu, Feb 4, 2021 at 2:51 PM <keith@...> wrote: So after refitting the display selector board, the horizontal and vertical
boards and carefully checking the wiring, it was time to switch on... and
it worked! No wandering trace anymore, the zero button zeroed it, the cal
button moved the spot to the opposite corner. Amazing what just cleaning a
few switches can do.
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Re: Tek 4041 GPIB Controller
I completed my port of the classic Adventure game to the Tektronix 4041!
All the files have been uploaded to my 4041 program repository in the Games/Adventure folder:
I started with my Adventure port to the 4052/4054 computers - a lot of 4041 BASIC commands are the same, the work was around the differences :)
This program should run on any 4041 with a working tape or DDU floppy or hard disk.
The screenshot link below was from using Tera Term on my Windows 10 laptop:
I will now work on removing the dependency for the tape/floppy/hard disk since the minimum memory of the 4041 is 128KB, I may be able to combine all the files into the main program.
You will still need the Program Development Option ROM as the program files are ASCII text and have to be parsed by the Program Development ROMs.
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Re: Slightly OT: OK Electronics tinyscope --Little CRTs Overview
The 200 series page at shows a 1" CRT prototype that's been restored after nearly 50 years.
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Attilio
Eric Schumacher
Martin
Bruce Lane
Gary Robert Bosworth