Date   

Re: Replacing cable on P6075A probe

Colin Herbert
 

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
Daveolla
Sent: 17 November 2020 17:44
To: TekScopes@groups.io
Subject: Re: [TekScopes] Replacing cable on P6075A probe
Greeting, Also, take note of what the manual says about shortening
the cable and Connector Replacement" page 2 ( 6 of 11) of the P6075A
version from the links given earlier in this thread;
http://w140.com/tekwiki/wiki/P6075
It is also repeated (or vise versa) in the plain P6075 manual on page
5 at the same link.
It states;
"Substitution of non-standard parts is not advisable if the original
performance is to be restored. Even shortening the cable by more than
a few percent will have a noticeable effect on the transient response
of the probe. The resistive center conductor has been specifically
selected for critical dampening of reflections that would otherwise
exist."

And then is the "Conector Replacement" next with step 1 as "Remove
the snap- fit cover on the compensation box." They dont tell you how
to do that though. Perhaps the plastic has stiffened
somewhat suggesting you need a good pry from a screwdriver. Perhaps
a blade edge of knife gently if a finger nail wont budge it. It can
also be stuck and needs to be cracked loose. If you nick or dint then
you gotta fix that somehow........or I do. Leave no marks is the goal.
Im sure we have all seen somones attempt at opening stuff up, TVs,
phones, etc that looked like a jackhammer attacked it everywhere. Use
a screwdriver for what it was intended, prying open paint cans!!!
So why is it called a screwdriver and not a paintcanpryer? Sorry, but I can
be a bit funny about the misuse of tools - I hope you were joking, here.

On a side note, what is the difference in the plain P6075 and the A
version? I see the specs for the plain versions input impedance is
10meg within 0.4% and 0.5% for the A.
Dave
At 07:51 AM 11/17/2020, you wrote:
Not quite right to compare 250 to 10Meg and declare 200 to be
therefore ok. By that logic, zero ohms should be just fine, too.
Yet, Tek went to the trouble to use resistance wire. Clearly there's a
reason!

The purpose of the resistance wire is to damp out reflections due to
mismatch. There's a Goldilocks optimum for each length that balances
bandwidth against aberrations. If you deviate from that balance,
either parameter degrades.

That said, you're probably not going to notice any dramatic change.
But if you had before and after measurements, you'd see a difference.

Tom

Sent from my iThing, so please excuse the terseness and typos

On Nov 17, 2020, at 5:24, "Brent W8XG" <brent@pwg.net> wrote:

No, I did not do a YouTube video. But I've seen one out there. I
didn't have a replacement cable or other parts. I cut my cable off
at both ends as close as I could to the strain-relief parts, then
tested the cable. It tested good, so I knew I'd cut out somewhere
the break. I used the typical wire strippers to remove the
insulation. I was very slow and methodical. But I was surprised at
how fine that wire was. Then I had to clean out both strain
relief's, with a Dremel. Once cleaned out, I pried them open just a
little, to be able to slip the cable in and then crimp.

So my cable is now a little shorter. The 250 ohm's is likely
about right given the size of the wire, but I didn't measure it. So
my cable might be 200 ohm's now. But with the 9k resistor in there
to make it a 10x probe, I doubt it matters much.

I don't know what the grommet is for. Maybe it's to slip over the
cable and then crimp to become strain relief??

Regards,






Re: Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology, History, and Applications"

Daveolla
 

You could make a nice bug zapper with all those wires, and repurpose its HV supply at the same time!
Dave

At 10:59 AM 11/17/2020, you wrote:
On 11/16/20 9:58 PM, Chuck Harris wrote re trinitrons:
It really was an economy in design. The electronics was simplified,
and the accuracy and brightness of the screen was greatly improved.
Thanks for that reverse engineering analysis. Sounds like the concepts the original designer could have thought dealing with when coming up with the taught wires method.




Re: Replacing cable on P6075A probe

Daveolla
 

Ya, I have a handy jar with about 5 or 6 of those paint openers, 2 styles. They work real good. They could make screwdrivers obsolete! Now if they had a gizmo to put the lid back on the paint can it might obsolete hammers.. Once the lid pounding dents the side of the can, the lid never goes back on well, too much springiness or bounce in the lid rim.

Dave

At 10:53 AM 11/17/2020, you wrote:
Or use one of those handy metal thingies from Home Depot to open paint cans if you're here in the States. Doubles as a bottle opener so you can have a cold one while you paint! Don't blame me if your paint job doesn't come out so great, though. ;)

Jim Ford

------ Original Message ------
From: "Daveolla" <grobbins@netflash.net>
To: TekScopes@groups.io
Sent: 11/17/2020 9:44:13 AM
Subject: Re: [TekScopes] Replacing cable on P6075A probe

Greeting, Also, take note of what the manual says about shortening the cable and Connector Replacement" page 2 ( 6 of 11) of the P6075A version from the links given earlier in this thread;

http://w140.com/tekwiki/wiki/P6075

It is also repeated (or vise versa) in the plain P6075 manual on page 5 at the same link.
It states;

"Substitution of non-standard parts is not advisable if the original performance is to be restored. Even shortening the cable by more than a few percent will have a noticeable effect on the transient response of the probe. The resistive center conductor has been specifically selected for critical dampening of reflections that would otherwise exist."

And then is the "Conector Replacement" next with step 1 as "Remove the snap- fit cover on the compensation box." They dont tell you how to do that though. Perhaps the plastic has stiffened somewhat suggesting you need a good pry from a screwdriver. Perhaps a blade edge of knife gently if a finger nail wont budge it. It can also be stuck and needs to be cracked loose. If you nick or dint then you gotta fix that somehow........or I do. Leave no marks is the goal.

Im sure we have all seen somones attempt at opening stuff up, TVs, phones, etc that looked like a jackhammer attacked it everywhere. Use a screwdriver for what it was intended, prying open paint cans!!!

On a side note, what is the difference in the plain P6075 and the A version? I see the specs for the plain versions input impedance is 10meg within 0.4% and 0.5% for the A.

Dave


Re: Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology, History, and Applications"

John Griessen
 

On 11/16/20 9:58 PM, Chuck Harris wrote re trinitrons:
It really was an economy in design. The electronics was simplified,
and the accuracy and brightness of the screen was greatly improved.
Thanks for that reverse engineering analysis. Sounds like the concepts the original designer could have thought dealing with when coming up with the taught wires method.


Re: Replacing cable on P6075A probe

Jim Ford
 

Or use one of those handy metal thingies from Home Depot to open paint cans if you're here in the States. Doubles as a bottle opener so you can have a cold one while you paint! Don't blame me if your paint job doesn't come out so great, though. ;)

Jim Ford

------ Original Message ------
From: "Daveolla" <grobbins@netflash.net>
To: TekScopes@groups.io
Sent: 11/17/2020 9:44:13 AM
Subject: Re: [TekScopes] Replacing cable on P6075A probe

Greeting, Also, take note of what the manual says about shortening the cable and Connector Replacement" page 2 ( 6 of 11) of the P6075A version from the links given earlier in this thread;

http://w140.com/tekwiki/wiki/P6075

It is also repeated (or vise versa) in the plain P6075 manual on page 5 at the same link.
It states;

"Substitution of non-standard parts is not advisable if the original performance is to be restored. Even shortening the cable by more than a few percent will have a noticeable effect on the transient response of the probe. The resistive center conductor has been specifically selected for critical dampening of reflections that would otherwise exist."

And then is the "Conector Replacement" next with step 1 as "Remove the snap- fit cover on the compensation box." They dont tell you how to do that though. Perhaps the plastic has stiffened somewhat suggesting you need a good pry from a screwdriver. Perhaps a blade edge of knife gently if a finger nail wont budge it. It can also be stuck and needs to be cracked loose. If you nick or dint then you gotta fix that somehow........or I do. Leave no marks is the goal.

Im sure we have all seen somones attempt at opening stuff up, TVs, phones, etc that looked like a jackhammer attacked it everywhere. Use a screwdriver for what it was intended, prying open paint cans!!!

On a side note, what is the difference in the plain P6075 and the A version? I see the specs for the plain versions input impedance is 10meg within 0.4% and 0.5% for the A.

Dave

At 07:51 AM 11/17/2020, you wrote:
Not quite right to compare 250 to 10Meg and declare 200 to be therefore ok. By that logic, zero ohms should be just fine, too. Yet, Tek went to the trouble to use resistance wire. Clearly there's a reason!

The purpose of the resistance wire is to damp out reflections due to mismatch. There's a Goldilocks optimum for each length that balances bandwidth against aberrations. If you deviate from that balance, either parameter degrades.

That said, you're probably not going to notice any dramatic change. But if you had before and after measurements, you'd see a difference.

Tom

Sent from my iThing, so please excuse the terseness and typos

On Nov 17, 2020, at 5:24, "Brent W8XG" <brent@pwg.net> wrote:

No, I did not do a YouTube video. But I've seen one out there. I didn't have a replacement cable or other parts. I cut my cable off at both ends as close as I could to the strain-relief parts, then tested the cable. It tested good, so I knew I'd cut out somewhere the break. I used the typical wire strippers to remove the insulation. I was very slow and methodical. But I was surprised at how fine that wire was. Then I had to clean out both strain relief's, with a Dremel. Once cleaned out, I pried them open just a little, to be able to slip the cable in and then crimp.

So my cable is now a little shorter. The 250 ohm's is likely about right given the size of the wire, but I didn't measure it. So my cable might be 200 ohm's now. But with the 9k resistor in there to make it a 10x probe, I doubt it matters much.

I don't know what the grommet is for. Maybe it's to slip over the cable and then crimp to become strain relief??

Regards,










Re: Replacing cable on P6075A probe

Daveolla
 

Greeting, Also, take note of what the manual says about shortening the cable and Connector Replacement" page 2 ( 6 of 11) of the P6075A version from the links given earlier in this thread;

http://w140.com/tekwiki/wiki/P6075

It is also repeated (or vise versa) in the plain P6075 manual on page 5 at the same link.
It states;

"Substitution of non-standard parts is not advisable if the original performance is to be restored. Even shortening the cable by more than a few percent will have a noticeable effect on the transient response of the probe. The resistive center conductor has been specifically selected for critical dampening of reflections that would otherwise exist."

And then is the "Conector Replacement" next with step 1 as "Remove the snap- fit cover on the compensation box." They dont tell you how to do that though. Perhaps the plastic has stiffened somewhat suggesting you need a good pry from a screwdriver. Perhaps a blade edge of knife gently if a finger nail wont budge it. It can also be stuck and needs to be cracked loose. If you nick or dint then you gotta fix that somehow........or I do. Leave no marks is the goal.

Im sure we have all seen somones attempt at opening stuff up, TVs, phones, etc that looked like a jackhammer attacked it everywhere. Use a screwdriver for what it was intended, prying open paint cans!!!

On a side note, what is the difference in the plain P6075 and the A version? I see the specs for the plain versions input impedance is 10meg within 0.4% and 0.5% for the A.

Dave

At 07:51 AM 11/17/2020, you wrote:
Not quite right to compare 250 to 10Meg and declare 200 to be therefore ok. By that logic, zero ohms should be just fine, too. Yet, Tek went to the trouble to use resistance wire. Clearly there's a reason!

The purpose of the resistance wire is to damp out reflections due to mismatch. There's a Goldilocks optimum for each length that balances bandwidth against aberrations. If you deviate from that balance, either parameter degrades.

That said, you're probably not going to notice any dramatic change. But if you had before and after measurements, you'd see a difference.

Tom

Sent from my iThing, so please excuse the terseness and typos

On Nov 17, 2020, at 5:24, "Brent W8XG" <brent@pwg.net> wrote:

No, I did not do a YouTube video. But I've seen one out there. I
didn't have a replacement cable or other parts. I cut my cable off at both ends as close as I could to the strain-relief parts, then tested the cable. It tested good, so I knew I'd cut out somewhere the break. I used the typical wire strippers to remove the insulation. I was very slow and methodical. But I was surprised at how fine that wire was. Then I had to clean out both strain relief's, with a Dremel. Once cleaned out, I pried them open just a little, to be able to slip the cable in and then crimp.

So my cable is now a little shorter. The 250 ohm's is likely
about right given the size of the wire, but I didn't measure it. So my cable might be 200 ohm's now. But with the 9k resistor in there to make it a 10x probe, I doubt it matters much.

I don't know what the grommet is for. Maybe it's to slip over the
cable and then crimp to become strain relief??

Regards,






Re: Tek 577 D1 Repair (B07xxxx)

Jack2015
 

4. (B108xxx,My 2nd 577 D1)
2020-Nov-2~8: Max 8 traces displayed on screen(9 lines included the baseline)

Checked the staircase signal:
Saw only 8 steps, 660mV /per step <-------NG (should be 10 steps,500mV/step)
https://groups.io/g/TekScopes/photo/255563/1?p=Created,,,100,2,0,0

Adjusted the step amplitude VR(A1 Board) and got the staircase of 10 steps (500mV/step).
https://groups.io/g/TekScopes/photo/255563/3?p=Created,,,100,2,0,0
https://groups.io/g/TekScopes/photo/255563/0?p=Created,,,100,2,0,0

5.(B108xxx,My 2nd 577 D1)
2020-Nov-9~15: The Collector supply disabled light turned on right at power on.

Checked Q588(2N2222,50V,0.8A):
Vc=+12V
Vb=+1.3V <-------NG Vbe=+1.3-(-12)=13.3V>>0.7V
Ve=-12V
Vbe open

https://groups.io/g/TekScopes/photo/255563/4?p=Created,,,100,2,0,0

Fixed this issue by replacing the 2N2222 with a 2sc1384(50V,1A).

https://groups.io/g/TekScopes/photo/255563/2?p=Created,,,100,2,0,0


Re: Replacing cable on P6075A probe

Tom Lee
 

Not quite right to compare 250 to 10Meg and declare 200 to be therefore ok. By that logic, zero ohms should be just fine, too. Yet, Tek went to the trouble to use resistance wire. Clearly there's a reason!

The purpose of the resistance wire is to damp out reflections due to mismatch. There's a Goldilocks optimum for each length that balances bandwidth against aberrations. If you deviate from that balance, either parameter degrades.

That said, you're probably not going to notice any dramatic change. But if you had before and after measurements, you'd see a difference.

Tom

Sent from my iThing, so please excuse the terseness and typos

On Nov 17, 2020, at 5:24, "Brent W8XG" <brent@pwg.net> wrote:

No, I did not do a YouTube video. But I've seen one out there. I didn't have a replacement cable or other parts. I cut my cable off at both ends as close as I could to the strain-relief parts, then tested the cable. It tested good, so I knew I'd cut out somewhere the break. I used the typical wire strippers to remove the insulation. I was very slow and methodical. But I was surprised at how fine that wire was. Then I had to clean out both strain relief's, with a Dremel. Once cleaned out, I pried them open just a little, to be able to slip the cable in and then crimp.

So my cable is now a little shorter. The 250 ohm's is likely about right given the size of the wire, but I didn't measure it. So my cable might be 200 ohm's now. But with the 9k resistor in there to make it a 10x probe, I doubt it matters much.

I don't know what the grommet is for. Maybe it's to slip over the cable and then crimp to become strain relief??

Regards,





Re: Q122/222 Jfet J300 subs for 2215A scope ?

Tom Lee
 

As I've said a couple of times, that circuit is very tolerant of FET parameters. It was designed to avoid the expense of matched FETs, so I very much doubt that any selection was involved here.

Are you certain that you are inserting these various JFETs correctly? Pinouts are not standardized. Perhaps you are assuming that they are.

Again, that circuit is just not fussy. Your problem lies somewhere else.

Tom

Sent from my iThing, so please excuse the terseness and typos

On Nov 16, 2020, at 6:35, charlesterrebonne@hotmail.com wrote:

thanks to all who replied - the 2215A scope is off the bench for now but Ill get back to it soon and will report when I get this working...I am almost at the point of sticking a high quality transistor socket there and just trying some other close to J300 specs Jfets I have on hand...FYI all the parts I have tried in the Q122/Q222 position in the scope : 2N3918, NTE133, k19, NTE132 tested good out of circuit...i have some more Jfet #s in my stock I need to try.

From the Tektronix replaceable parts reg. : 151-1124-00 = Siliconix J-2400...would'nt be surprised this was not a custom design but more likely tested/hand picked J300s jfets and assigned a Tektronix custom part# from Siliconix...searching Siliconix j-2400 brings up nothing...Id suspect most input boards from that 22xx series scopes came off the assembly line with "J300" marked Jfets in those Q122/222 positions..thanks





Re: Replacing cable on P6075A probe

Brent W8XG
 

No, I did not do a YouTube video. But I've seen one out there. I didn't have a replacement cable or other parts. I cut my cable off at both ends as close as I could to the strain-relief parts, then tested the cable. It tested good, so I knew I'd cut out somewhere the break. I used the typical wire strippers to remove the insulation. I was very slow and methodical. But I was surprised at how fine that wire was. Then I had to clean out both strain relief's, with a Dremel. Once cleaned out, I pried them open just a little, to be able to slip the cable in and then crimp.

So my cable is now a little shorter. The 250 ohm's is likely about right given the size of the wire, but I didn't measure it. So my cable might be 200 ohm's now. But with the 9k resistor in there to make it a 10x probe, I doubt it matters much.

I don't know what the grommet is for. Maybe it's to slip over the cable and then crimp to become strain relief??

Regards,


Re: Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology, History, and Applications"

Chuck Harris <cfharris@...>
 

Well, that is sort of right.

There was only one electron gun structure, but it had 3 cathodes, one
for each color. There was no fancy electronic stuff, though. It was
exactly the same as the other color crt's in that regard.

The shadow mask was where it was all at. Because there was only one
gun structure, and the cathodes (emitters) for that gun were lined up
horizontally, the shadow mask was able to be made with a far simpler
structure. It was simply a bunch of very fine wires, under high tension,
that went from the top to the bottom of the screen.

Because a shadow mask gets hit by the high energy electron beam, it gets
hot and expands... especially when displaying a bright screen. This
caused the conventional shadow mask, with its triad holes, to smear its
colors when very bright... The trinitron's high tension wire shadow mask
simply grew longer, and stayed taught. This kept the colors accurate at
high screen brightness... a major win for Sony.

The special sauce was the lack of tops and bottoms to the phosphor stripes.

The vertical wires allowed much more exposed phosphor to be excited, and
as a result a much brighter screen could be had with a trinitron than was
possible with a shadow mask drilled full of holes.

Because the wires that formed the shadow mask were under tension, and
were vertical required the screen to be cylindrical, rather than
spherical as was used in the GE triple gun CRT's. This was simpler, and
allowed greater accuracy.... only being curved in one dimension.

It really was an economy in design. The electronics was simplified,
and the accuracy and brightness of the screen was greatly improved.

-Chuck Harris

Stephen Hanselman wrote:

I don’t have hard knowledge of that but the big deal about Trinitron wasn't the mask. It was the fact that there was only one electron gun and some pretty intricate electronic stuff done to emulate the three-gun standard color tubes. The benefit was overcoming the very difficult task of keeping the three gun cluster aligned in manufacture.

I can also say from experience if you don't feel real confident and have detailed instructions and test equipment don't try to align a Trinitron. The 9845 color head was one of the best it had a very nice calibration program built in

Steve


-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of snapdiode via groups.io
Sent: Monday, November 16, 2020 9:59 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology, History, and Applications"

I'm a bit confused about the Trinitron having "dots", the Trinitron relies on stripes and the mask is an aperture grille.












Re: Replacing cable on P6075A probe

 

On Mon, Nov 16, 2020 at 02:07 PM, Brent W8XG wrote:

I had a break. I cut the cable at both ends. There is a strain relief fitting, and I used a small Dremel drill to
remove the extra material. Then I went to work on the cable. The probe wire is the finest, smallest wire
I've ever see. It took some time and was quite tedious. But I got it done. It was a couple of hours.
Brent, did you also make a YouTube video about the process? I believe I watched such a video when I was first considering doing this; it was daunting, but encouraging.

I have what appears to be a complete kit for replacement of the cable, and it looks relatively straightforward (except for the bit about soldering a wire that is thinner than a human hair!), but I have several questions about the process:

1. The compensation box end of the cable has a significant extra length of insulated cable (about 2cm in excess of what is necessary) and I don't have any special tools to cut and strip the insulation from a coaxial cable of this small diameter (or any coaxial cable for that matter, but I can easily strip regular RG58 with an Xacto knife). How would you suggest stripping the insulation off the extra length of cable?

2. There is an extra part in the kit, a tiny grommet about 2mm long and 2mm in diameter at the flanged end. The instructions do not mention this grommet at all, and I don't see anything similar to it in the existing probe. Is this something that is needed for some probes (but not, presumably, for my P6075A)?

3. I checked the resistance of the new cable and the damaged cable, both read about 250 Ohms. This is a bit lower than I expected. Does this sound correct?

I will try to upload pictures of the kit to the photos section under an album titled "P6075A Replacement Cable"


Re: Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology, History, and Applications"

Roy Thistle
 

On Mon, Nov 16, 2020 at 02:29 PM, greenboxmaven wrote:


Tektronix made color studio video monitors that used Sony Trinitron jugs
IMO, the Trinitron based Tek monitors have excellent colour.
Trinitron was the best colour CRT... far better than any competitor, when first introduced... and superior, in the consumer market up until 1996? when Sony lost the patent.
AFAIK, the "magic" was in the aperture grill (it's not right to call that a shadow mask.) According to the literature, this conveyed most of the advantages that made the Trinitron superior.
Perhaps the one flaw... noticed, only if you look for it... is that the aperture grid's stabilization wires are sometimes visible.
Interesting things happen with loud (very loud) music and Tinitron based broadcast monitors.


Re: Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology, History, and Applications"

greenboxmaven
 

It is absolutely true. A consciencous station would have one or two typical home color TVs, connected to good outdoor antennas and not cable, in the control room to see and know what their viewers were seeing at home. Because of the design compromises of consumer TVs, especially in the color decoding circuitry and the lack of DC restoration, tweaks were made to be sure the home viewer was pleased. I worked in the TV repair craft between 1967 and 77, and there was a lot progress made and very bad compromises as well. Remember, a nice 23 inch console color set would cost $2500-4000 in today's money. Now you can buy a 45 inch high definition hang on the wall flat screen color set for $300 or less.

Bruce Gentry, KA2IVY

On 11/16/20 3:48 PM, stevenhorii wrote:
In the days of color CRTs for television, I knew a guy who worked in a
broadcast studio. Though Trinitron displays (Tektronix made a display
monitor that used a Trinitron CRT) were used in the control room of the
studio, he said that they also had a conventional triangular dot shadow
mask monitor as that was what most home TVs used and they wanted to be sure
that the broadcast image looked as good on the triangle shadow mask monitor
as it did on the Trinitron ones. Whether or not this is true, I don't know.

Steve H.

On Mon, Nov 16, 2020 at 3:38 PM Dennis Tillman W7pF <dennis@ridesoft.com>
wrote:

Hi Barry,
As with so many things there is an excellent explanation on Wikipedia of
shadow mask and Trinitron tubes and how they work. It is at
https://en.wikipedia.org/wiki/Cathode-ray_tube.
Scroll down to the section I am referring to. No magic is involved, just a
shadow mask.
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of n4buq
Sent: Monday, November 16, 2020 9:43 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Special Offer from Peter Keller to TekScopes
Members: The Cathode Ray Tube, Technology, History, and Applications"

Hi Tom,

My question is probably quite simple but, like I said, I'm not finding a
good answer.

As I understand it (and from personal observation when I had a Trinitron
TV and I'm primarily wondering about this type of CRT but the question
probably applies to others), the screen has groupings of RBG phospher dots
and the RGB guns "activate" those dots as needed; however, what I'm not
understanding is how a given gun "activates" a given dot. Is a particular
phosphor dot sensitive to a property of one of the color guns such that a
blue dot ignores a red gun, etc.? If so, then I can somewhat understand it
but I'm wondering if I'm way off in that assumption.

The various sites just seem to indicate there are three guns, each of
which magically cause a given color to appear but it's not explained how a
single color gun causes a corresponding dot to glow without affecting the
ones around it.

(Hope that made sense...)

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Tom Lee" <tomlee@ee.stanford.edu>
To: TekScopes@groups.io
Sent: Monday, November 16, 2020 11:27:46 AM
Subject: Re: [TekScopes] Special Offer from Peter Keller to TekScopes
Members: The Cathode Ray Tube, Technology, History, and Applications"

Hi Barry,

Pete's book mainly covers electrostatically deflected crts. Except for
some very early models, TVs used magnetically deflected crts (to allow
large screens without absurd set depths). The guns are similar, but
the deflection methods are very different because of the different
optimization objectives.

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 11/16/2020 07:18, n4buq wrote:
Does anyone know whether this book covers CRTs that were used for
color TVs (and other color displays)? I ask because I'm not finding
good information on how those work.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Dennis Tillman W7pF" <dennis@ridesoft.com>
To: TekScopes@groups.io
Sent: Monday, November 16, 2020 12:15:11 AM
Subject: Re: [TekScopes] Special Offer from Peter Keller to
TekScopes
Members: The Cathode Ray Tube, Technology, History, and
Applications"

Hi Chris,
I don't expect any problems shipping this to Germany.

One correction:
This offer is strictly between Peter Keller and individual members
of the group. I did offer to act as the go-between because I
thought there might be some interest and because I understood how
"sensitive" our members are to price. I was also hoping this would
give Peter some well-deserved cash as we get close to the holidays.

So I told Peter I thought I might be able to pass along 10 orders
for his book. When he said OK I notified TekScopes. That was 36
hours ago. I have orders for over 50 of his books as of this moment.

This brings back memories of when I asked for small donations to
pay Groups.io the annual fee for hosting TekScopes back at the
beginning of the year. Somebody please remind me the next time I
think up something like this to think twice about what happened the
last two times I had a bright idea.
:)

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
ChrisBeee via groups.io
Sent: Sunday, November 15, 2020 8:47 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Special Offer from Peter Keller to
TekScopes
Members: The Cathode Ray Tube, Technology, History, and Applications"

Hi Dennis,
I would be more than glad if I could support the group buy and get
a copy of Peter's book, many thanks for making this possible! My
only concern is if you would ship to Germany too. I will send you a
PM with my contact data.
Cheers
Chris







--
Dennis Tillman W7pF
TekScopes Moderator















--
Dennis Tillman W7pF
TekScopes Moderator








Tektronix Type 555 Dual Beam Oscilloscope

Bill Higdon
 


Re: Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology, History, and Applications"

greenboxmaven
 

Tektronix made color studio video monitors that used Sony Trinitron jugs. In good condition and properly set up, the picture is excellent.

Bruce Gentry, KA2IVY

On 11/16/20 12:43 PM, n4buq wrote:
Hi Tom,

My question is probably quite simple but, like I said, I'm not finding a good answer.

As I understand it (and from personal observation when I had a Trinitron TV and I'm primarily wondering about this type of CRT ........
(Hope that made sense...)

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Tom Lee" <tomlee@ee.stanford.edu>
To: TekScopes@groups.io
Sent: Monday, November 16, 2020 11:27:46 AM
Subject: Re: [TekScopes] Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology,
History, and Applications"

Hi Barry,

Pete's book mainly covers electrostatically deflected crts. Except for
some very early models, TVs used magnetically deflected crts (to allow
large screens without absurd set depths). The guns are similar, but the
deflection methods are very different because of the different
optimization objectives.

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 11/16/2020 07:18, n4buq wrote:
Does anyone know whether this book covers CRTs that were used for color TVs
(and other color displays)? I ask because I'm not finding good
information on how those work.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Dennis Tillman W7pF" <dennis@ridesoft.com>
To: TekScopes@groups.io
Sent: Monday, November 16, 2020 12:15:11 AM
Subject: Re: [TekScopes] Special Offer from Peter Keller to TekScopes
Members: The Cathode Ray Tube, Technology,
History, and Applications"

Hi Chris,
I don't expect any problems shipping this to Germany.

One correction:
This offer is strictly between Peter Keller and individual members of the
group. I did offer to act as the go-between because I thought there might
be
some interest and because I understood how "sensitive" our members are to
price. I was also hoping this would give Peter some well-deserved cash as
we
get close to the holidays.

So I told Peter I thought I might be able to pass along 10 orders for his
book. When he said OK I notified TekScopes. That was 36 hours ago. I have
orders for over 50 of his books as of this moment.

This brings back memories of when I asked for small donations to pay
Groups.io the annual fee for hosting TekScopes back at the beginning of
the
year. Somebody please remind me the next time I think up something like
this
to think twice about what happened the last two times I had a bright idea.
:)

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
ChrisBeee
via groups.io
Sent: Sunday, November 15, 2020 8:47 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Special Offer from Peter Keller to TekScopes
Members: The Cathode Ray Tube, Technology, History, and Applications"

Hi Dennis,
I would be more than glad if I could support the group buy and get a copy
of
Peter's book, many thanks for making this possible! My only concern is if
you would ship to Germany too. I will send you a PM with my contact data.
Cheers
Chris







--
Dennis Tillman W7pF
TekScopes Moderator













Re: Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology, History, and Applications"

Harvey White
 

The guns are indeed the same.  The electrons are the same. However, the shadow mask is the key.  The guns are in a triangle. If each gun were aimed at the exact surface of the screen, then each beam would hit the same spot.  However, the actual point where the beams are focused is a little inside where the phosphor is, so the three beams would cross, and then diverge.  Think three chopsticks making a very small triangle, crossing, and then diverging to the guns.

If you put a mask (with a hole in it at exactly the intersection of the three beams, they get narrowed.  The beam coming through the shadow mask hits a different color phosphor depending on which gun sends out the beam.

It's all in the angles.

Harvey

On 11/16/2020 3:56 PM, n4buq wrote:
Hi Dennis,

I had been to that page yesterday and I didn't quite understand some of it. Particularly, the following image wasn't helping that much.

https://en.wikipedia.org/wiki/Cathode-ray_tube#/media/File:CRT_color_enhanced.png

The reason being that they "paint" the color guns as if they're somehow controlling what color the phosphor will be when, in fact, that was just for clarification to show that the "red" gun was being aimed (through the hole in the mask) at the red phosphor, the "blue" gun at the blue phosphor, and the "green" gun at the green phosphor. The guns are all the same and it is only the phosphor that's different and that was what I was wondering. Perhaps a silly question but it was confusing me nonetheless. I understand it now (actually, Tom Lee helped explain it via a PM).

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Dennis Tillman W7pF" <dennis@ridesoft.com>
To: TekScopes@groups.io
Sent: Monday, November 16, 2020 2:38:24 PM
Subject: Re: [TekScopes] Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology,
History, and Applications"

Hi Barry,
As with so many things there is an excellent explanation on Wikipedia of
shadow mask and Trinitron tubes and how they work. It is at
https://en.wikipedia.org/wiki/Cathode-ray_tube.
Scroll down to the section I am referring to. No magic is involved, just a
shadow mask.
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of n4buq
Sent: Monday, November 16, 2020 9:43 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Special Offer from Peter Keller to TekScopes
Members: The Cathode Ray Tube, Technology, History, and Applications"

Hi Tom,

My question is probably quite simple but, like I said, I'm not finding a good
answer.

As I understand it (and from personal observation when I had a Trinitron TV
and I'm primarily wondering about this type of CRT but the question probably
applies to others), the screen has groupings of RBG phospher dots and the
RGB guns "activate" those dots as needed; however, what I'm not
understanding is how a given gun "activates" a given dot. Is a particular
phosphor dot sensitive to a property of one of the color guns such that a
blue dot ignores a red gun, etc.? If so, then I can somewhat understand it
but I'm wondering if I'm way off in that assumption.

The various sites just seem to indicate there are three guns, each of which
magically cause a given color to appear but it's not explained how a single
color gun causes a corresponding dot to glow without affecting the ones
around it.

(Hope that made sense...)

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Tom Lee" <tomlee@ee.stanford.edu>
To: TekScopes@groups.io
Sent: Monday, November 16, 2020 11:27:46 AM
Subject: Re: [TekScopes] Special Offer from Peter Keller to TekScopes
Members: The Cathode Ray Tube, Technology, History, and Applications"

Hi Barry,

Pete's book mainly covers electrostatically deflected crts. Except for
some very early models, TVs used magnetically deflected crts (to allow
large screens without absurd set depths). The guns are similar, but
the deflection methods are very different because of the different
optimization objectives.

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 11/16/2020 07:18, n4buq wrote:
Does anyone know whether this book covers CRTs that were used for
color TVs (and other color displays)? I ask because I'm not finding
good information on how those work.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Dennis Tillman W7pF" <dennis@ridesoft.com>
To: TekScopes@groups.io
Sent: Monday, November 16, 2020 12:15:11 AM
Subject: Re: [TekScopes] Special Offer from Peter Keller to
TekScopes
Members: The Cathode Ray Tube, Technology, History, and
Applications"

Hi Chris,
I don't expect any problems shipping this to Germany.

One correction:
This offer is strictly between Peter Keller and individual members
of the group. I did offer to act as the go-between because I
thought there might be some interest and because I understood how
"sensitive" our members are to price. I was also hoping this would
give Peter some well-deserved cash as we get close to the holidays.

So I told Peter I thought I might be able to pass along 10 orders
for his book. When he said OK I notified TekScopes. That was 36
hours ago. I have orders for over 50 of his books as of this moment.

This brings back memories of when I asked for small donations to
pay Groups.io the annual fee for hosting TekScopes back at the
beginning of the year. Somebody please remind me the next time I
think up something like this to think twice about what happened the
last two times I had a bright idea.
:)

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
ChrisBeee via groups.io
Sent: Sunday, November 15, 2020 8:47 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Special Offer from Peter Keller to
TekScopes
Members: The Cathode Ray Tube, Technology, History, and Applications"

Hi Dennis,
I would be more than glad if I could support the group buy and get
a copy of Peter's book, many thanks for making this possible! My
only concern is if you would ship to Germany too. I will send you a
PM with my contact data.
Cheers
Chris







--
Dennis Tillman W7pF
TekScopes Moderator















--
Dennis Tillman W7pF
TekScopes Moderator








Tektronix 7D13 and 7A42 wanted

Sparky99
 

Hi everyone, I'm searching for the above in good condition - if you have one for sale please let me know. I'm based in Switzerland, so prefer Europe but am also open to paying postage from US if I can't find anything closer to home.

Cheers

Sparky


Re: Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology, History, and Applications"

snapdiode
 

Well, really, a shadow mask uses the parallax effect.


Re: Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology, History, and Applications"

n4buq
 

Hi Dennis,

I had been to that page yesterday and I didn't quite understand some of it. Particularly, the following image wasn't helping that much.

https://en.wikipedia.org/wiki/Cathode-ray_tube#/media/File:CRT_color_enhanced.png

The reason being that they "paint" the color guns as if they're somehow controlling what color the phosphor will be when, in fact, that was just for clarification to show that the "red" gun was being aimed (through the hole in the mask) at the red phosphor, the "blue" gun at the blue phosphor, and the "green" gun at the green phosphor. The guns are all the same and it is only the phosphor that's different and that was what I was wondering. Perhaps a silly question but it was confusing me nonetheless. I understand it now (actually, Tom Lee helped explain it via a PM).

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Dennis Tillman W7pF" <dennis@ridesoft.com>
To: TekScopes@groups.io
Sent: Monday, November 16, 2020 2:38:24 PM
Subject: Re: [TekScopes] Special Offer from Peter Keller to TekScopes Members: The Cathode Ray Tube, Technology,
History, and Applications"

Hi Barry,
As with so many things there is an excellent explanation on Wikipedia of
shadow mask and Trinitron tubes and how they work. It is at
https://en.wikipedia.org/wiki/Cathode-ray_tube.
Scroll down to the section I am referring to. No magic is involved, just a
shadow mask.
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of n4buq
Sent: Monday, November 16, 2020 9:43 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Special Offer from Peter Keller to TekScopes
Members: The Cathode Ray Tube, Technology, History, and Applications"

Hi Tom,

My question is probably quite simple but, like I said, I'm not finding a good
answer.

As I understand it (and from personal observation when I had a Trinitron TV
and I'm primarily wondering about this type of CRT but the question probably
applies to others), the screen has groupings of RBG phospher dots and the
RGB guns "activate" those dots as needed; however, what I'm not
understanding is how a given gun "activates" a given dot. Is a particular
phosphor dot sensitive to a property of one of the color guns such that a
blue dot ignores a red gun, etc.? If so, then I can somewhat understand it
but I'm wondering if I'm way off in that assumption.

The various sites just seem to indicate there are three guns, each of which
magically cause a given color to appear but it's not explained how a single
color gun causes a corresponding dot to glow without affecting the ones
around it.

(Hope that made sense...)

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Tom Lee" <tomlee@ee.stanford.edu>
To: TekScopes@groups.io
Sent: Monday, November 16, 2020 11:27:46 AM
Subject: Re: [TekScopes] Special Offer from Peter Keller to TekScopes
Members: The Cathode Ray Tube, Technology, History, and Applications"

Hi Barry,

Pete's book mainly covers electrostatically deflected crts. Except for
some very early models, TVs used magnetically deflected crts (to allow
large screens without absurd set depths). The guns are similar, but
the deflection methods are very different because of the different
optimization objectives.

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 11/16/2020 07:18, n4buq wrote:
Does anyone know whether this book covers CRTs that were used for
color TVs (and other color displays)? I ask because I'm not finding
good information on how those work.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Dennis Tillman W7pF" <dennis@ridesoft.com>
To: TekScopes@groups.io
Sent: Monday, November 16, 2020 12:15:11 AM
Subject: Re: [TekScopes] Special Offer from Peter Keller to
TekScopes
Members: The Cathode Ray Tube, Technology, History, and
Applications"

Hi Chris,
I don't expect any problems shipping this to Germany.

One correction:
This offer is strictly between Peter Keller and individual members
of the group. I did offer to act as the go-between because I
thought there might be some interest and because I understood how
"sensitive" our members are to price. I was also hoping this would
give Peter some well-deserved cash as we get close to the holidays.

So I told Peter I thought I might be able to pass along 10 orders
for his book. When he said OK I notified TekScopes. That was 36
hours ago. I have orders for over 50 of his books as of this moment.

This brings back memories of when I asked for small donations to
pay Groups.io the annual fee for hosting TekScopes back at the
beginning of the year. Somebody please remind me the next time I
think up something like this to think twice about what happened the
last two times I had a bright idea.
:)

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
ChrisBeee via groups.io
Sent: Sunday, November 15, 2020 8:47 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Special Offer from Peter Keller to
TekScopes
Members: The Cathode Ray Tube, Technology, History, and Applications"

Hi Dennis,
I would be more than glad if I could support the group buy and get
a copy of Peter's book, many thanks for making this possible! My
only concern is if you would ship to Germany too. I will send you a
PM with my contact data.
Cheers
Chris







--
Dennis Tillman W7pF
TekScopes Moderator


















--
Dennis Tillman W7pF
TekScopes Moderator





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