Date   

Re: recommended ESR meters these days

Lawrance A. Schneider
 


Re: recommended ESR meters these days

David Kuhn
 

My shipping was $9.60 USPS. I am looking forward to it.

I am also looking for a Leakseeker 89A. No one is making that anymore.
EDS sells the parts for $99 and the PCB is one ebay for $30 and the case
for $35. I am tempted to order all that stuff an build one.

Dave

On Tue, Mar 17, 2020 at 7:39 PM Reginald Beardsley via Groups.Io <pulaskite=
yahoo.com@groups.io> wrote:

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




Re: Tek 5441 Scope

aldue
 

Did you try Sphere Research Corp. Website or phone 250 769 1834 also look for bad resistors before replacing the transistors. I wrecked 2 transistors and found that a resistor had cooked, loosing 80% of its resistance.


Re: Tek 5441 Scope

magnustoelle
 

Good day,
Walter with Sphere seems to have some available; https://www.sphere.bc.ca/test/tek-parts/tekparts2.html 
But unless my memory fades me, this is a simple darlington npn transistor; which I have replaced with a type TIP122 in an older repair. That type is commonly available; i.e. made by ON Semi to date.

Good luck with your repair,
Magnus
Does anyone have a source for Q910 part number 151-0331-00  or  151-0496-00 or a cross reference it appears to be an NPN darlington transistor.  R911 on the power supply board is getting very hot, and Q910 appears to be shorted.    Thanks


Tek 5441 Scope

rbassham@...
 

Does anyone have a source for Q910 part number 151-0331-00 or 151-0496-00 or a cross reference it appears to be an NPN darlington transistor. R911 on the power supply board is getting very hot, and Q910 appears to be shorted. Thanks


Re: Grey, blue or clear? filter colors

Edward Prest
 

Thank you guys. I need to read the long ref carefully.
My 466 has p2 blue green becoming green crt (phosphor) . I would think a green filter would be better than blue. I will try a green gel vs blue tonight.
and polarization is a good point too. 3M used to make special filters - like louvers to aid vis in sunlight of led displays = way back now.


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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software.
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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!