Date   
Re: Grey, blue or clear? filter colors

Dave Seiter
 

My favorites are the mesh filters for the 7K series, then the blue ones.
-Dave

On Tuesday, March 17, 2020, 04:32:44 PM PDT, Edward Prest <prest.edward.3@...> wrote:

Lightweight topic but curious to the color CRT filter choices available - and why?
Is clear for photography?
Blue to match the corporate identity?
I'm guessing that grey is to max the contrast in bright areas.
There is (was) a dark screen which is super fragile but works well. My 422 has that.

What else is there?

Re: Grey, blue or clear? filter colors

Richard Knoppow
 

The document I cited refers to another, a paper by W.T. Dyall. It can be found at:
*https://dspace.mit.edu/bitstream/handle/1721.1/4992/RLE-TR-056-04706923.pdf*

On 3/17/2020 4:32 PM, Edward Prest wrote:
Lightweight topic but curious to the color CRT filter choices available - and why?
Is clear for photography?
Blue to match the corporate identity?
I'm guessing that grey is to max the contrast in bright areas.
There is (was) a dark screen which is super fragile but works well. My 422 has that.

What else is there?


--
Richard Knoppow
dickburk@...
WB6KBL

Re: Grey, blue or clear? filter colors

Richard Knoppow
 

The filters can be for a couple of purposes. First the "gray" filters are probably polarizing filters. These can be circularly polarized where light going through the filter from the outside and reflected from the face of the crt is reversed in its direction of rotation. When these work right no light should be reflected from the CRT. They are not quite that effective but can considerably improve contrast where there must be ambient light.
   There is another kind of filter that appears gray, that is a fine conductive mesh or coating which reduces radiation of RF from the face of the CRT. Very often both a mesh and color filter are found. The mesh filter will also increase visual contrast simply because the trace only has to go through it once while light reflected from the surface of the CRT must go through twice. However, its main function is as an RF shield.
   Color filters also serve to improve the contrast of the trace by transmitting the light from the phosphor freely but cutting down on other colors. There is another purpose for colored filters, that is to select the time constant of the trace. Note that all phosphors have a _fluorescence_ and a _phosphorescence_ The first is the primary light emitted when the electron beam hits the phosphor, the second is the "after glow" after the beam goes away. They are sometimes of different colors. For instance one of them as a very short fluorescence which is blue and a very long phosphorescence which is orange. If you want to use the very short florescence to photograph pulses, for instance, you use a blue or UV filter. If you are using the long persistence orange trace, for instance for radar, you use an orange filter, which cuts off the bright blue short persistence trace so as not to desensitize the eye. Many phosphors have fluorescence and phosphorescence of about the same color so the color filter is mostly to cut down on ambient light and improve the visual contrast of the trace.
     A PDF showing all CRT phosphors with their colors and the persistence or decay characteristics is at:
http://www.bunkerofdoom.com/tubes/crt/crt_phosphor_research.pdf

  Note P-14 as an example of different decay for different colors.

On 3/17/2020 4:32 PM, Edward Prest wrote:
Lightweight topic but curious to the color CRT filter choices available - and why?
Is clear for photography?
Blue to match the corporate identity?
I'm guessing that grey is to max the contrast in bright areas.
There is (was) a dark screen which is super fragile but works well. My 422 has that.

What else is there?


--
Richard Knoppow
dickburk@...
WB6KBL

Re: Beware of cheap "crock-a-gator" clips

Raymond Cote
 

Thanks Dave. I found some bad ines also. They were one i git in amazon cheap so tossed the bunch. As to your recommendations i made my own.

On Mar 17, 2020, at 16:08, ArtekManuals <manuals@...> wrote:

I was recently troubleshooting a piece of equipment. Like many of you I often use "crock-a-gator" clips (piece of wire with a alligator clip on either end) to access and hold a measurement point on a component on a PCb while I take measurements, power the assembly outside of its mother ship, etc.

Recently at one of the local ham/tailgate swap meets, I picked up a bundle of these clips with their multi color wires and clips covers at a bargain price as my old set was getting a bit ragged. Today I was taking some measurements and the readings were quite erratic, this in a circuit that didn't have any� erratic behavior before. Further checking I found that this 1ft wire with clips on either end i was using� had a resistance (jumping) around between 1 and 2 K ohms ! Upon closer inspection I found that wire had simply been folded back under the insulation and the whole assembly crimped, NO SOLDER!. I started checking and even the "good" ones measured between 2 and 4 ohms . I thought oh well I 'll just solder them and everything will be fine. The resistance on the soldered cables now down around 1.5 ohms still not great if used to jumper any current carrying circuit. Further inspection revealed that the wire was 7 strands of #35 wire !! or the equivalent of about #28 . ...

Conclusions

1) Yet another instance of� a "gift" from China
2) Please until you have gone and checked your own clips dont trust them to take readings with.
3) If you want good c-g-clip jumpers ...make them yourself out of at least #18 wire

Just a heads up , Go measure your C-G-Clips to determine what you have before making measurements and getting bad data

PLEASE DO NOT TO TURN THIS INTO� ANOTHER NEVER ENDING THREAD WITH WAR STORIES OF SIMILAR EXPERIENCE..This thread should be enough

Regards
Dave
manuals@...


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Manuals@...
www.ArtekManuals.com


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492 AP 3rd Mixer or Custom IC needed

Doug Wilson
 

Have had not any luck finding the 3rd Mixer module (119-2008-00). If anyone has a spare please contact me.

As an alternate, the specific part that has failed is a custom Tektronix hybrid IC
155-0285-00
Microcircuit Calibrator

Any hep is appreciated.

Re: Grey, blue or clear? filter colors

Brad Thompson
 

Edward Prest wrote on 3/17/2020 7:32 PM:

Lightweight topic but curious to the color CRT filter choices available - and why?
Is clear for photography?
Blue to match the corporate identity?
I'm guessing that grey is to max the contrast in bright areas.
There is (was) a dark screen which is super fragile but works well. My 422 has that.

What else is there?

Hello--

IIRC, there's also a metal-mesh screen filter that's used on scopes that had
to meet certain EMI criteria. At one point, I had one for a 453.73--

Brad  AA1IP

Re: recommended ESR meters these days

Reginald Beardsley
 

Does anyone have experience with the EDS-89 LeakSeeker? It's no longer sold, but there are PCBs on ebay and kits of parts available from Dave Miga, the designer. Looks to be around $150 or so with a good case.

In a world where service data is often not available, that and the EDS-88A look very attractive with the potential to rescue a lot of stuff from an early grave without a lot of time invested in the repair.

Reg

Grey, blue or clear? filter colors

Edward Prest
 

Lightweight topic but curious to the color CRT filter choices available - and why?
Is clear for photography?
Blue to match the corporate identity?
I'm guessing that grey is to max the contrast in bright areas.
There is (was) a dark screen which is super fragile but works well. My 422 has that.

What else is there?

Re: Beware of cheap "crock-a-gator" clips

Edward Prest
 

The smaller the clip and wire - the faster they go open. Rework is expected!

Re: recommended ESR meters these days

Dave Daniel
 

I had a recent experience with excessive shipping charges.

I wanted to order some smoked Swiss cheese inline, which I can’t find here where I live but found at a very reasonable price online. The order total was ~$14, but when shipping and handling charges were added, the order total was $40. So I called the company on the telephone to complain. The person I spoke with took my order and charged me about $6 for shipping and handling (and the order was for 2x the amount of cheese I was trying to buy online).

So, the lesson was, call before giving up. It seems that many companies are aware of and sensitive to the problem of excessive shipping charges.

On Mar 17, 2020, at 18:51, Dennis McCreery <@dennismc> wrote:

Wow, $66.00 for shipping? Not for me!

Regards,

Dennis


Re: Beware of cheap "crock-a-gator" clips

Dwayne Reid
 

Good day to all.

My attitude towards those really cheap clip leads is simple: I treat them as a really inexpensive way to get the raw materials to make my own clip leads. The wire is absolutely trash but the clips and boots are usually pretty good.

I use good-quality wire (usually Belden or Alpha) of the appropriate colors and just make a couple of batches from brand-new junky leads.

Works well for me.

dwayne

PS - we used to call them "One Ohm Resistors" back when the quality was much better than now. Yeah - the cheap Chinese clip leads of today are in fact much worse than in past years.

dwayne

At 03:29 PM 3/17/2020, n4buq wrote:

I'll have to check mine. The worst problem I've had with them (hope this isn't a war story) is the rubber boots harden with age. I can barely open the alligator's jaws on mine anymore.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "ArtekManuals" <manuals@...>
To: TekScopes@groups.io
Sent: Tuesday, March 17, 2020 4:08:27 PM
Subject: [TekScopes] Beware of cheap "crock-a-gator" clips

I was recently troubleshooting a piece of equipment. Like many of you I
often use "crock-a-gator" clips (piece of wire with a alligator clip on
either end) to access and hold a measurement point on a component on a
PCb while I take measurements, power the assembly outside of its mother
ship, etc.

Recently at one of the local ham/tailgate swap meets, I picked up a
bundle of these clips with their multi color wires and clips covers at a
bargain price as my old set was getting a bit ragged. Today I was taking
some measurements and the readings were quite erratic, this in a circuit
that didn't have any� erratic behavior before. Further checking I found
that this 1ft wire with clips on either end i was using� had a
resistance (jumping) around between 1 and 2 K ohms ! Upon closer
inspection I found that wire had simply been folded back under the
insulation and the whole assembly crimped, NO SOLDER!. I started
checking and even the "good" ones measured between 2 and 4 ohms . I
thought oh well I 'll just solder them and everything will be fine. The
resistance on the soldered cables now down around 1.5 ohms still not
great if used to jumper any current carrying circuit. Further inspection
revealed that the wire was 7 strands of #35 wire !! or the equivalent of
about #28 . ...

Conclusions

1) Yet another instance of� a "gift" from China
2) Please until you have gone and checked your own clips dont trust them
to take readings with.
3) If you want good c-g-clip jumpers ...make them yourself out of at
least #18 wire

Just a heads up , Go measure your C-G-Clips to determine what you have
before making measurements and getting bad data

PLEASE DO NOT TO TURN THIS INTO� ANOTHER NEVER ENDING THREAD WITH WAR
STORIES OF SIMILAR EXPERIENCE..This thread should be enough

Regards
Dave
manuals@...


--
Dave
Manuals@...
www.ArtekManuals.com


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--
Dwayne Reid <dwayner@...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
780-489-3199 voice 780-487-6397 fax 888-489-3199 Toll Free
www.trinity-electronics.com
Custom Electronics Design and Manufacturing

Re: recommended ESR meters these days

Dennis McCreery
 

Wow, $66.00 for shipping? Not for me!

Regards,

Dennis

Re: Beware of cheap "crock-a-gator" clips

n4buq
 

I'll have to check mine. The worst problem I've had with them (hope this isn't a war story) is the rubber boots harden with age. I can barely open the alligator's jaws on mine anymore.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "ArtekManuals" <manuals@...>
To: TekScopes@groups.io
Sent: Tuesday, March 17, 2020 4:08:27 PM
Subject: [TekScopes] Beware of cheap "crock-a-gator" clips

I was recently troubleshooting a piece of equipment. Like many of you I
often use "crock-a-gator" clips (piece of wire with a alligator clip on
either end) to access and hold a measurement point on a component on a
PCb while I take measurements, power the assembly outside of its mother
ship, etc.

Recently at one of the local ham/tailgate swap meets, I picked up a
bundle of these clips with their multi color wires and clips covers at a
bargain price as my old set was getting a bit ragged. Today I was taking
some measurements and the readings were quite erratic, this in a circuit
that didn't have any� erratic behavior before. Further checking I found
that this 1ft wire with clips on either end i was using� had a
resistance (jumping) around between 1 and 2 K ohms ! Upon closer
inspection I found that wire had simply been folded back under the
insulation and the whole assembly crimped, NO SOLDER!. I started
checking and even the "good" ones measured between 2 and 4 ohms . I
thought oh well I 'll just solder them and everything will be fine. The
resistance on the soldered cables now down around 1.5 ohms still not
great if used to jumper any current carrying circuit. Further inspection
revealed that the wire was 7 strands of #35 wire !! or the equivalent of
about #28 . ...

Conclusions

1) Yet another instance of� a "gift" from China
2) Please until you have gone and checked your own clips dont trust them
to take readings with.
3) If you want good c-g-clip jumpers ...make them yourself out of at
least #18 wire

Just a heads up , Go measure your C-G-Clips to determine what you have
before making measurements and getting bad data

PLEASE DO NOT TO TURN THIS INTO� ANOTHER NEVER ENDING THREAD WITH WAR
STORIES OF SIMILAR EXPERIENCE..This thread should be enough

Regards
Dave
manuals@...


--
Dave
Manuals@...
www.ArtekManuals.com


--
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Beware of cheap "crock-a-gator" clips

ArtekManuals
 

I was recently troubleshooting a piece of equipment. Like many of you I often use "crock-a-gator" clips (piece of wire with a alligator clip on either end) to access and hold a measurement point on a component on a PCb while I take measurements, power the assembly outside of its mother ship, etc.

Recently at one of the local ham/tailgate swap meets, I picked up a bundle of these clips with their multi color wires and clips covers at a bargain price as my old set was getting a bit ragged. Today I was taking some measurements and the readings were quite erratic, this in a circuit that didn't have any� erratic behavior before. Further checking I found that this 1ft wire with clips on either end i was using� had a resistance (jumping) around between 1 and 2 K ohms ! Upon closer inspection I found that wire had simply been folded back under the insulation and the whole assembly crimped, NO SOLDER!. I started checking and even the "good" ones measured between 2 and 4 ohms . I thought oh well I 'll just solder them and everything will be fine. The resistance on the soldered cables now down around 1.5 ohms still not great if used to jumper any current carrying circuit. Further inspection revealed that the wire was 7 strands of #35 wire !! or the equivalent of about #28 . ...

Conclusions

1) Yet another instance of� a "gift" from China
2) Please until you have gone and checked your own clips dont trust them to take readings with.
3) If you want good c-g-clip jumpers ...make them yourself out of at least #18 wire

Just a heads up , Go measure your C-G-Clips to determine what you have before making measurements and getting bad data

PLEASE DO NOT TO TURN THIS INTO� ANOTHER NEVER ENDING THREAD WITH WAR STORIES OF SIMILAR EXPERIENCE..This thread should be enough

Regards
Dave
manuals@...


--
Dave
Manuals@...
www.ArtekManuals.com


--
This email has been checked for viruses by Avast antivirus software.
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Re: recommended ESR meters these days

David Kuhn
 

" EDS-88A CapAnalyzer Series II

If you do a lot of repair work it is the best ESR meter hands down. It's
not cheap but worth it. I own one and it's great. Mercedelectronics.com"

It is $229 on their web site, $260 on ebay. I just ordered one direct from
their website.

That YouTube video definitely sells it.

On Mon, Mar 16, 2020 at 9:34 PM Randy.AB9GO <@AB9GO> wrote:

EDS-88A CapAnalyzer Series II

If you do alot of repair work it is the best ESR meter hands down. It's
not cheap but worth it. I own one and it's great. Mercedelectronics.com

Randy AB9GO




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Re: Tektronix Probe Tips DIY

Daveolla
 

Greetings, Ive made up several tips for the scope probe tip into a suitable sized square connector with short wire to grabber hooks or connector (square pin or round machined ) to fit the Tek grapper pin.

Find a dowel a bit bigger than the probe barrel, or exact size if your lucky, perhaps a pencil. Chuck it in your favorite chuck, lathe, drill press, or hand drill. Then turn or file it to the proper diameter. Make it a tad longer than needed so you can trim to exact size later. Leave a taper or little flare up to a slightly larger diameter of the dowel. Trim to the length you want. To get a tad fancier, leave a length at the tip end turned down to the diameter of the connector. Or if a pencil or softer "lead" of a coloured pencil was used drill it out and glue a toothpick into the hole, perhaps a masking tape thin strip wrapped around it to center it in the hole, and hit with crazy glue.

Now get your heatshrink (not the shiny stuff) and slip it on the dowel and give it a shrink. Chuck the dowel again and with a blade sitting on the drill press table, slide it into the slowly spinning heatshrink at the larger after taper section of the dowel. This give a nice lead intro the probe tip as well as stiffens the end.

Trim the connecter end to the length you need and slide the connector with wire into the heatshrink and carefully shrink it or glue it in place. Before doing this try it on the probe with the connector so you know where it goes.

You can whip up a pile nice and fast and they look good.

Not that I would do this in this application as you want some softness and stretch of the heatshrink to grip the barrel, but a crazy glue coating on the surface of heatshrink gives a nice shiny hard surface, the not shiny heatshrink type almost seems to absorb the glue in to its matte finish. And if a black sharpie is used on the surface first, the crazy glue will dissolve it and you have a nice shiny black hard crazy glue coating.
Dave
(more of my post below)


At 02:30 AM 3/16/2020, you wrote:
Similar techniques can be extended to add a low-inductance ground bayonet/spear to a probe, as found in the HP10020 1.5GHz passive resistive divider probe:
https://www.eevblog.com/forum/testgear/fifty-ohm-probes/?action=dlattach;attach=135831;PHPSESSID=lohekcsu194l3qpirrh4ps38p2
or the hp10431 "high" impedance passive probe:
https://www.eevblog.com/forum/buysellwanted/how-much-should-i-pay-for-a-500mhz-10x-passive-oscilloscope-probe/?action=dlattach;attach=109603;image

Suitable materials are Shapeways' nylon (slightly flexible), or DirtyPCB's SLA (smooth high resolution). The latter is stunningly cheap, but takes a while to arrive.
The Tek P6046 diff probe came with what looks like some circuit board fuse clips that fit the probe ground barrel, a little tab on then can be soldered onto your test board.
Hp 3406 sampling meter also had what looks like fuse clips with a short 1/2 stiff pin soldered on and parallel to the tip. It can be slide up and down the ground barrel to adjust the pins position. They also used them with a 1" insulated wire with an alligator clip. I have also seen lately instead of a stiff pin, a maybe 1/4"wide brass strip used. It is J shaped and maybe an inch long. One end is soldered to the clip, the other end is cut to make a pointed tip. If the Jbend was not theres not there, picture the clip on the probe with the pointed tip pointing up towards your hand, bending it down towards the tip gives the J and adjustment.. The wide strip reduces the inductance better than the wire versions.

I hope all of my post here makes sense, I seem to be suffering from a slow keyboard today, I type and letters show up fifteen seconds or so later, backspacing and erasing stuff and waiting for results ended up taking a few hours to get this all composed.
Dave

On 16/03/20 02:45, Harvey White wrote:
One of the major problems with both Tektronix and HP probes is frequently the lack of tips. I do digital logic work, and after quite a while I managed to find a pair (both different) Tektronix tips which terminate in a wire with a connector suitable for a 0.025 inch (standard wirewrap) pin.

I got tired of not having more. I looked at Mouser (where I could find the equivalent ground leads for 5 mm diameter Tek & HP probes), I looked on Ebay. Nothing.

So I decided to see what I could do on my own. The average female/female jumper cable (available cheaply on Amazon or Ebay) fits well enough over the probe tip, but the piece of plastic is a bit harder (read impossible) to find.

Fortunately, I do have a 3D printer. So you start with a cylinder, hollow it out enough to fit over the ground barrel of a 5.0 mm probe, put a square hole in it to hold the one pin connector plastic for a female dupont connector, taper the tip, and make a through hole that’s large enough to allow the connector (minus plastic) to fit through. Do that, push the plastic on one end into the cap, put the plastic part back on, and then you have a probe tip that allows you to put the tip on a standard 5mm probe.

If the connector for the probe tip has a limited life, the jumper wires are quite cheap. You could also put one in for a female to male and connect directly to a breadboard.

If anyone wants the .stl files, please email me. I’ll also give you the .scad files if you wish. This is available for non-commercial use. I’m not posting the files here since anything posted becomes the property of groups.io.


Harvey

Re: recommended ESR meters these days

David Kuhn
 

I want on - 8-). I just watched the YouTube video. I think I am ordering
one.

Dave

On Mon, Mar 16, 2020 at 9:34 PM Randy.AB9GO <@AB9GO> wrote:

EDS-88A CapAnalyzer Series II

If you do alot of repair work it is the best ESR meter hands down. It's
not cheap but worth it. I own one and it's great. Mercedelectronics.com

Randy AB9GO




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Re: Unique Scope Option

cmjones01
 

I had a 7603 like that. It was the variant with the spectrum analyzer
graticule, if that makes any difference. It did struggle a bit to give a
sharp trace at decent brightness in a brightly-lit room, but perhaps the
(normal, green) CRT was tired.

Chris

On Tue, 17 Mar 2020, 16:56 Eric, <ericsp@...> wrote:

This 7603 has a green Phosphor tube. Not the P11 so it is even stranger.
If a picture will help let me know ill be glad to post one.

On 3/17/2020 11:50 AM, Bruce Atwood wrote:
Perhaps to control reflected light. Reflected light goes through the
filter twice while light from the phosphor once.

Re: Unique Scope Option

Mlynch001
 

This subject just made me look! Both my 7623A and 7633 have the Dark Gray implosion shields with a black band around the circumference of the shield. They are both "Standard" P31 phosphor. I never had paid attention to this in the past, just assumed that the grey shield was "Standard" TEK issue?

--
Michael Lynch
Dardanelle, AR

Re: Unique Scope Option

Eric
 

This 7603 has a green Phosphor tube. Not the P11 so it is even stranger. If a picture will help let me know ill be glad to post one.

On 3/17/2020 11:50 AM, Bruce Atwood wrote:
Perhaps to control reflected light. Reflected light goes through the filter twice while light from the phosphor once.