Date   

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

tekscopegroup@...
 

There is a lot of cheap chinese crap jumper going around. Some do not even use copper. I once had to troubleshoot an intermittent in an AC extension cord bought at the supermarket. The ones with the thick orange cable that you would guess would at least have a 3x #16 or #14 inside. Turns out the orange rubber layer was 95% of the diameter, and only two thin maybe #26 wires where running through it. So they definitively know how to save on copper and potentially burning down houses.

The best alligator jumpers for me have always been the ones Radio Shack used to sell, the mid-size 4-color set, with two of each. Decent diameter real copper wire (altough not even close to handle more than 5 amps without losses) and quite consistent albeit crimped construction, and the right size alligator clip for most jobs. I am still using the 2-3 sets all the time that I purchased a long time ago, and only very occasionally do I have to cut and resolder one side when the copper conductor breaks at the usual flexing point near the clip.

Anything else out there I ever tried was very crappy. I recall once ordering a set from BGMicro or AllElect that looked good in the picture but each wire measured btw 15-25 ohms!! I There where only like 3-4 very fine stands in each wire, and it did not even look like copper, probably was recycled tin. Replaced all the wires and only reused the clips, but typical the wires one has around are stiffer so they see very little use, and over time the clips also have become very stiff to open and close even tough there is no visible deterioration or corrosion.


Re: Grey, blue or clear? filter colors

Eric
 

I am looking for some of the filters. I have a 7603 on the bench but the filter is almost black. I cant see the graticule at all with out the illumination turned on. My older one has a clear. Ill deffinatly have to do an LED upgrade to the lights on this one.

On 3/18/2020 1:57 AM, Dave Seiter wrote:
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: Beware of cheap "crock-a-gator" clips

Harold Foster
 

It's really not that expensive to buy the clips and various colored covers from Mouser or Digikey... and this lets you deal with known quality items in the sizes you want. I used to be all for the cheap ones made out of Chinesium until the boot on one just split and shorted out the power supply on a HP 8663A I was working on. After that, $25 worth of parts really didn't seem that bad. Sigh.

Hal


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

kim.herron@sbcglobal.net
 

I discovered that a long time ago.  Years.  The only positive from these things
is they are a cheap source of alligator clips and boots.  Some decent stranded wire
and the Weller fixes them right up.

Kim Herron
W8ZV

On 18 Mar 2020 at 1:39, Raymond Cote wrote:

Thanks Dave. I found some bad ones 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@...


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


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Kim Herron  W8ZV
1-616-677-3706


Re: Grey, blue or clear? filter colors

tek_547
 

Interesting pdf´s Richard, thanx for that.
René


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@...


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


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492 AP 3rd Mixer or Custom IC needed

Doug Wilson <calmissile@...>
 

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


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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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