TekScopes@groups.io

Re: General Radio 874 Connector, inner conductor "bendies"

On 8/11/2019 2:12 AM, Jim Ford wrote:

Along with the APC 7mm connectors, they are the only genderless RF/microwave connectors I know of.? I've avoided both in my garage lab, in favor of SMA, BNC, and type N, since all of those are much more common.Because I own a number of GR instruments that use 874 output connectors I have many 874 cables as well as many GR between-series adapters to adapt 874 to BNC, N, PL-259/SO-239, and a few others.
-- 
Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA

Re: General Radio 874 Connector, inner conductor "bendies"

#158710

On 8/10/2019 7:55 PM, Dennis Tillman W7PF wrote:

General Radio made outstanding products. Few companies make products that ae still in use 75 or 100 years after they were designed.Dennis is correct. The oldest GR instrument in use on my bench is a Type1231-B Amplifier and Null Detector and its accessory Type 1231-P2 Tuned Circuit, both ca. 1950 (my 1231-B is the early design). They are used as the detector for audio-frequency measurements with my GR Type 1603-A Z-Y Bridge. In the field I frequently use my GR Type 1606-A RF Bridge and Type 1330-A Bridge Oscillator (both ca. 1960) for making impedance measurements on AM broadcast antenna systems. I have many other GR instruments, such as my Type 1602-AB UHF Admittance Meter, that see only occasional use in the field. Over the years I have accumulated a large tackle case of 874 cables, adapters, and other accessories, as well as some NOS 874 connectors for repair purposes. I used one of those NOS connectors several years ago when restoring a GR Type 805-C Standard Signal Generator which someone had butchered by replacing its 874 output connector with an SO-239.

I have owned even older GR instruments - I owned and regularly used, from ca. 1978 to ca. 2000, a GR Type 605-A Standard Signal Generator (ca. 1939), which was replaced by the 805-C. I own some GR decade resistors ca. 1930.

The Variac has been in widespread use for 85 years. I'll bet that at least 50% of the TekScopes members have one and that it gets used.One of my three is on the bench in a custom enclosure with fusing, metering, and an isolation transformer.

GR-874 connectors aren't quite that old - only 70 years now - but they too are still in widespread use.In addition to my dozens of GR-made 874 items I have nine Tek-branded 874 items, some of which see occasional use in the shop or the field.
-- 
Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA

Saving A5 Timing Board NVRAM calibration constants CSA803 (A/C) and 11801(B/C)

#158709

Dear all,

A couple of months ago, I obtained a CSA803A. When searching the internet and this Tek forum about CSA803X and 11801X scopes, I came across several messages related to the A5 Timing Board NVRAMs’ (U500 and U511) errors E5622 and T1331. These errors occur when an NVRAM battery has gone low. These NVRAMs (U500 and U511) consist of a DS1213B smart socket, containing a backup battery, which is the socket for a regular SRAM. When the battery fails, the NVRAM can be replaced by a new one, and after starting the scope it will function again. However, with a failing battery valuable calibration constants to enhance the time interpolator linearity, that are set at the time of manufacturing, are lost (e.g. see page 6-106 of the CSA803A/C service manual). With a new NVRAM, the scope will work again, but with reduced accuracy.
To prevent loss of this calibration data for a scope which still has the original NVRAMs, this information can be read from the chip using an EPROM  programmer and stored in a file. The procedure is as follows. Remove the NVRAMs from the Timing Board, IMPORTANT: this is the combination of the DS1213B smart socket with SRAM in it, i.e. do not remove the SRAM from the smart socket. Since the combination of the smart socket DS1213B and the 256kb SRAM is equivalent to a DS1230AB NVRAM (see ), choose in the programmer the DS1230AB as the chip to work on and read the content of the SRAM. 
Now in case an NVRAM fails in the future, the old NVRAM can be replaced with a DS1230AB and programmed with the saved content.
I expect this to work also on the CSA803/11801A scopes.

Kind regards,
Gerard Janssen

pictures added: the 5223 digitizing

#158708

/g/TekScopes/album?id=94145

Re: Is an early 7A26 a keeper?

#158707

Hi Jim,
I never noticed this before. I checked mine and I have six that are 20pF and seven that are 22pF. Most of the 22pF ones are later serial numbers but there is one 22pF one that is not a later plugin so I have no idea what Tek was up to.

Dennis Tillman W7PF

Show quoted text

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Jim Ford
Sent: Saturday, August 10, 2019 11:43 PM

Say, speaking of 7A26's, I was just looking at the input capacitances of my various vertical amplifier plug-ins to assess compatibility of those probes Chris Wilkson just put up FS.  I noticed that the two 7A26s that I have show different input capacitances.  One, serial number B210363, reads 22 pF, while S/N B191130 reads 20 pF!  I never noticed that before.

I assume Tek either intentionally increased the capacitance by 2 pF or had a better idea of what the real value was by later in the production run.

BTW, all of my gear in my garage lab, Tek, HP, or other, has all the stickers, tags, scratches, etc. from when I got it.  This is because:

1) I'm not retired yet, and with a full-time job plus a wife and 2 teenage sons, I don't have the time to bother with cleaning these things up to a pristine state

2) Those "imperfections" give my gear character - it is really cool to have a 7603 with an Intel label on it!

That's my story, and I'm sticking to it!

Jim Ford

------ Original Message ------
From: "Dennis Tillman W7PF" <dennis@...>
To: [email protected]
Sent: 8/10/2019 2:17:30 PM
Subject: Re: [TekScopes] Is an early 7A26 a keeper?

Hi John,
With that serial number it sounds like it was a much later one. It is 
even possible it is among the last production run. If you look at the 
date codes on the ICs you may be able to tell what year it was made. I 
suspect you will find it was made in 1988 or 1989 just before Tek 
terminated the product line.

An early serial number would be one like this - B010100 - which is what 
Tek usually used as the first serial number for a production instrument.

Dennis Tillman W7PF

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of 
John Griessen
Sent: Thursday, August 08, 2019 5:36 PM
To: [email protected]
Subject: [TekScopes] Is an early 7A26 a keeper?

I was getting some extra 7A26's ready to sell, and came across 7A26 
B154366, which is an early one with the familiar aluminum isothermal 
clamp blocks for transistors in cans.

Is that just as good as a late model if it has mostly metal film resistors?
Is it worth keeping for repairability?

I see little failure in 7A26's... tear drop tantalums, scratchy knobs, 
stiff knobs, and dust under the attenuator contacts.

Keep or sell/toss?

P.S.

I've got an attic that needs to be cleaned out in preparation for 
moving to Albuquerque, and a server that can show you pictures of it's box contents.
Email me if interested in browsing that web server.




--
Dennis Tillman W7PF
TekScopes Moderator







-- 
Dennis Tillman W7PF
TekScopes Moderator

Re: General Radio 874 Connector, inner conductor "bendies"

#158706

Hi Jim,

GR connectors are more common in Europe than in the US where they have been experiencing a slow phase out. SMA is a very inexpensive design with excellent HF performance. Their size is a big plus too.  But before SMA came along GR was a reasonably priced way to get good HF performance. BNC cables are unreliable above 1GHz due to the poor tolerances of the connectors and the unreliable quality standards followed by most cable manufacturers who seem to be more concerned with cutting costs to the bone. 

A Variac is the most enduring, reliable, and practical, design variation of a autotransformer. GR licensed their Variac design to several other companies. Staco is one I see regularly, Powerstat is another one. There is also GE, Superior Electric, and a company bought the Variac name and named themselves Variac, Inc. They make Variacs themselves. 

The design is always identical to the original. Only the details change such as the power rating (300VA, 500VA, 600VA, 1KVA, 2KVA, etc), the voltage  rating (120VAC, 240VAC, 440VAC), the frequency its designed for (50Hz, 60 Hz, 400Hz) and the enclosure. Some have meters most do not. New ones these days have digital panel meters.

Dennis Tillman W7PF

Show quoted text

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Jim Ford
Sent: Saturday, August 10, 2019 11:13 PM
To: [email protected]
Subject: Re: [TekScopes] General Radio 874 Connector, inner conductor "bendies"

Hi, Dennis.

Interesting to know about GR and the 874 connectors.  I'm a bit too young to have seen much GR equipment in use (I'm 54, born in 1965), but I have run across the 874's a few times in my career.  Along with the APC 7mm connectors, they are the only genderless RF/microwave connectors I know of.  I've avoided both in my garage lab, in favor of SMA, BNC, and type N, since all of those are much more common.  Someday I may extend my collection to APC 3.5 mm and 2.92 mm (K connectors) to go to higher frequencies while still remaining mechanically compatible with SMA.  Too darned expensive to go to the incompatible 1.85 mm and 1.0 mm (about $1k apiece!  Yikes!)  I think 40 GHz with the K connectors is a good place to stop!

Regarding the Variac, I don't have one but do have a Staco model 500B autotransformer that I rescued from the dumpster at Raytheon where I work.  I haven't used it for anything yet, but someday (in retirement?) I want to use it to work on vacuum tube audio and guitar amplifiers.  I remember seeing at least one Variac, along with a very large Tek scope on a cart (maybe a 555?), and a large amount of HP gear, including a Nixie tube frequency counter and a waveguide frequency meter (a bizarre-looking glass cylinder with a big black knob on top), among other waveguide gear in my dad's microwave spectroscopy lab back in the 1970's.  I guess growing up with all that cool Tek and HP equipment was part of why I became an EE.  I actually started out in biochem in college but quickly switched to EE.

Anyway, I mostly wanted to get in the bit about the Staco autotransformer.  IIRC, I saw them on eBay for about $200.  Score!

Jim Ford

------ Original Message ------
From: "Dennis Tillman W7PF" <dennis@...>
To: [email protected]
Sent: 8/10/2019 4:55:40 PM
Subject: Re: [TekScopes] General Radio 874 Connector, inner conductor "bendies"

Hi Roy,

The design of the GR-874 is unique (except for its bigger brother) in the electronics industry. It is brilliant design which is why it has lasted so long.
The connectors are hermaphroditic, in other words it has both male and female parts so they can mate to themselves. There is no need for male plugs and female sockets.

To insure the outer leaves are positioned properly with each other it was necessary to place a slight outward bend (or flare) at the end of two opposite outer leaves on each GR-874 connector. This simple mechanical feature insure that the leaves properly position themselves with respect to each other each time you mate two GR-874 connectors. You will notice this also requires you to orient the connectors with a 90 degree turn between them so the leaves with the flair are always opposite leaves with no flair. This wasn't necessary to do for the leaves of the inner conductor. Instead two of the inner leaves are positioned ever so slightly inward closer to the center. This insures the leaves from the other connector (rotated 90 degrees) which our further out from the center will mate perfectly with them. The result is that the outer leaves form a circular pressurized contact with each other and the inner leaves do the same. The circular design with simple mechanical self-alignment insured excellent performance past 7GHz. They are rugged as well, and didn't require any special locking mechanism. GR manufactured numerous adapters, terminators, extenders, power splitters, detectors, slotted lines, tunable filters, etc.  with these connectors on them so it quickly became the standard HF connector in the electronics industry.

For more information see the article in the GR Experimenter from 1949 which introduced the GR-874:

ct_1948.pdf

To see some of the hundreds of things made with GR-874 connectors take a look at this 20 page long excerpt from the GR 1975 catalog:

General Radio made outstanding products. Few companies make products that ae still in use 75 or 100 years after they were designed. The Variac was one of their designs from 1934. They licensed the design to several other companies but the original design was so perfect that the other manufacturers always followed the same design principles. The Variac has been in widespread use for 85 years. I'll bet that at least 50% of the TekScopes members have one and that it gets used. GR-874 connectors aren't quite that old - only 70 years now - but they too are still in widespread use.

Dennis Tillman W7PF

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Roy 
Thistle
Sent: Tuesday, August 06, 2019 2:45 PM
To: [email protected]
Subject: [TekScopes] General Radio 874 Connector, inner conductor "bendies"

Hi All:
Apologies, if this has been covered (there are a lot of posts on 874!).. but the picture on Tekwiki of the GR-874 (the one with the plug facing the viewer... so you can see into it)… well that picture shows two of the leaves of the center conductor, bent in at the corners, and so having little "bendies" barbs, or tangs. (You have to see the picture!).
.
My initial question is… Is that normal, or is the center conductor of the connector damaged? (You can see a bit of those "bendies" on the leaves of the outer conductor, in the picture, too.) My initial guess is the matching, inserter GR-874, after being rotated, and mated, has damaged the insertee?  If so, how does the mated pair maintain 50 ohms?
Best regards and wishes.
Roy

--
Dennis Tillman W7PF
TekScopes Moderator

-- 
Dennis Tillman W7PF
TekScopes Moderator

Re: 7000 series empty plugin frame $12 shipped

#158705

Hi Chris,
Sorry, they are spoken for.
3 months ago I had two and I ended up giving them away. Nobody wanted them.
I will not be getting any more as far as I know.

That was the only 7000 series prototyping plugin except for a prototype kit (no built in amplifier) which had an entire PC board from front to back with solder pads (9.5" x 4.2" on 0.1" centers ~ 4000 pads) for prototyping. The rear of the board has a backplane connector on it and each finger from the backplane is brought out to a pad at the back of the board. 30 to 35 of the solder pads (less than 1%) on the boards I have were used once but I removed the wires that were in them. Those pads are perfectly usable.
	
I have some of those boards and could assemble the rest of the parts to make them into kits except for blank front panels and the front chassis plate that goes behind the front panel. Blank front panels are unobtanium (extremely rare). I can provide front chassis plates with a few holes already in them because those holes would usually be hidden by the front panel. I can provide each with a few random front chassis plates so you could find one that is best for your purposes. The rest of what needs to be included to make a kit (pull tab assemblies, rear panels, top and bottom rails, screws, attachment points for the PC boards, side panels, etc) are not a problem. 

Dennis Tillman W7PF

Show quoted text

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Chris Wilkson via Groups.Io
Sent: Saturday, August 10, 2019 6:24 PM
To: [email protected]
Subject: Re: [TekScopes] 7000 series empty plugin frame $12 shipped

Those 7A17's sound cool!  I'll take them (email sent).

What other prototyping options are there for 7K series?




-- 
Dennis Tillman W7PF
TekScopes Moderator

Re: oh yeah?

#158704

Hi Snapdiode,

For the past month and a half I haven't had a moment to myself. The constant pressure has been no fun at all.  That all changed today when I saw your post. Thank you.

I put a few pictures of the sampling heads and other related stuff I have up on TekScopes in the photo section. There is also a nice screen shot of the response of an S-42 (like yours) if you connect it to an OIG-502 Optical Impulse Generator.

The pictures are at: 
/g/TekScopes/album?id=94144

Dennis Tillman W7PF

Show quoted text

-----Original Message-----
Sent: Saturday, August 10, 2019 9:11 PM
Subject: Re: [TekScopes] oh yeah?

Pretty sure I'm the only one with four 1S2s, a 1L30, and a Type O on my street!
Maybe I'm just the prince of sampling heads. Come on, a S-42? How cool is that? :) It fits between my S-1, S-2, S-3, S-4, S-5, S-6 and just before my S-52.




-- 
Dennis Tillman W7PF
TekScopes Moderator

Re: Is an early 7A26 a keeper?

#158703

Say, speaking of 7A26's, I was just looking at the input capacitances of my various vertical amplifier plug-ins to assess compatibility of those probes Chris Wilkson just put up FS.  I noticed that the two 7A26s that I have show different input capacitances.  One, serial number B210363, reads 22 pF, while S/N B191130 reads 20 pF!  I never noticed that before.

I assume Tek either intentionally increased the capacitance by 2 pF or had a better idea of what the real value was by later in the production run.

BTW, all of my gear in my garage lab, Tek, HP, or other, has all the stickers, tags, scratches, etc. from when I got it.  This is because:

1) I'm not retired yet, and with a full-time job plus a wife and 2 teenage sons, I don't have the time to bother with cleaning these things up to a pristine state

2) Those "imperfections" give my gear character - it is really cool to have a 7603 with an Intel label on it!

That's my story, and I'm sticking to it!

Jim Ford

Show quoted text

------ Original Message ------
From: "Dennis Tillman W7PF" <dennis@...>
To: [email protected]
Sent: 8/10/2019 2:17:30 PM
Subject: Re: [TekScopes] Is an early 7A26 a keeper?

Hi John,
With that serial number it sounds like it was a much later one. It is even
possible it is among the last production run. If you look at the date codes
on the ICs you may be able to tell what year it was made. I suspect you will
find it was made in 1988 or 1989 just before Tek terminated the product
line.

An early serial number would be one like this - B010100 - which is what Tek
usually used as the first serial number for a production instrument.

Dennis Tillman W7PF

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of John
Griessen
Sent: Thursday, August 08, 2019 5:36 PM
To: [email protected]
Subject: [TekScopes] Is an early 7A26 a keeper?

I was getting some extra 7A26's ready to sell, and came across 7A26 B154366,
which is an early one with the familiar aluminum isothermal clamp blocks for
transistors in cans.

Is that just as good as a late model if it has mostly metal film resistors?
Is it worth keeping for repairability?

I see little failure in 7A26's... tear drop tantalums, scratchy knobs, stiff
knobs, and dust under the attenuator contacts.

Keep or sell/toss?

P.S.

I've got an attic that needs to be cleaned out in preparation for moving to
Albuquerque, and a server that can show you pictures of it's box contents.
Email me if interested in browsing that web server.

--
Dennis Tillman W7PF
TekScopes Moderator

Re: General Radio 874 Connector, inner conductor "bendies"

#158702

Hi, Dennis.

Interesting to know about GR and the 874 connectors.  I'm a bit too young to have seen much GR equipment in use (I'm 54, born in 1965), but I have run across the 874's a few times in my career.  Along with the APC 7mm connectors, they are the only genderless RF/microwave connectors I know of.  I've avoided both in my garage lab, in favor of SMA, BNC, and type N, since all of those are much more common.  Someday I may extend my collection to APC 3.5 mm and 2.92 mm (K connectors) to go to higher frequencies while still remaining mechanically compatible with SMA.  Too darned expensive to go to the incompatible 1.85 mm and 1.0 mm (about $1k apiece!  Yikes!)  I think 40 GHz with the K connectors is a good place to stop!

Regarding the Variac, I don't have one but do have a Staco model 500B autotransformer that I rescued from the dumpster at Raytheon where I work.  I haven't used it for anything yet, but someday (in retirement?) I want to use it to work on vacuum tube audio and guitar amplifiers.  I remember seeing at least one Variac, along with a very large Tek scope on a cart (maybe a 555?), and a large amount of HP gear, including a Nixie tube frequency counter and a waveguide frequency meter (a bizarre-looking glass cylinder with a big black knob on top), among other waveguide gear in my dad's microwave spectroscopy lab back in the 1970's.  I guess growing up with all that cool Tek and HP equipment was part of why I became an EE.  I actually started out in biochem in college but quickly switched to EE.

Anyway, I mostly wanted to get in the bit about the Staco autotransformer.  IIRC, I saw them on eBay for about $200.  Score!

Jim Ford

Show quoted text

------ Original Message ------
From: "Dennis Tillman W7PF" <dennis@...>
To: [email protected]
Sent: 8/10/2019 4:55:40 PM
Subject: Re: [TekScopes] General Radio 874 Connector, inner conductor "bendies"

Hi Roy,

The design of the GR-874 is unique (except for its bigger brother) in the electronics industry. It is brilliant design which is why it has lasted so long.
The connectors are hermaphroditic, in other words it has both male and female parts so they can mate to themselves. There is no need for male plugs and female sockets.

To insure the outer leaves are positioned properly with each other it was necessary to place a slight outward bend (or flare) at the end of two opposite outer leaves on each GR-874 connector. This simple mechanical feature insure that the leaves properly position themselves with respect to each other each time you mate two GR-874 connectors. You will notice this also requires you to orient the connectors with a 90 degree turn between them so the leaves with the flair are always opposite leaves with no flair. This wasn't necessary to do for the leaves of the inner conductor. Instead two of the inner leaves are positioned ever so slightly inward closer to the center. This insures the leaves from the other connector (rotated 90 degrees) which our further out from the center will mate perfectly with them. The result is that the outer leaves form a circular pressurized contact with each other and the inner leaves do the same. The circular design with simple mechanical self-alignment insured excellent performance past 7GHz. They are rugged as well, and didn't require any special locking mechanism. GR manufactured numerous adapters, terminators, extenders, power splitters, detectors, slotted lines, tunable filters, etc.  with these connectors on them so it quickly became the standard HF connector in the electronics industry.

For more information see the article in the GR Experimenter from 1949 which introduced the GR-874:

To see some of the hundreds of things made with GR-874 connectors take a look at this 20 page long excerpt from the GR 1975 catalog:

General Radio made outstanding products. Few companies make products that ae still in use 75 or 100 years after they were designed. The Variac was one of their designs from 1934. They licensed the design to several other companies but the original design was so perfect that the other manufacturers always followed the same design principles. The Variac has been in widespread use for 85 years. I'll bet that at least 50% of the TekScopes members have one and that it gets used. GR-874 connectors aren't quite that old - only 70 years now - but they too are still in widespread use.

Dennis Tillman W7PF

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Roy Thistle
Sent: Tuesday, August 06, 2019 2:45 PM
To: [email protected]
Subject: [TekScopes] General Radio 874 Connector, inner conductor "bendies"

Hi All:
Apologies, if this has been covered (there are a lot of posts on 874!).. but the picture on Tekwiki of the GR-874 (the one with the plug facing the viewer... so you can see into it)… well that picture shows two of the leaves of the center conductor, bent in at the corners, and so having little "bendies" barbs, or tangs. (You have to see the picture!).
.
My initial question is… Is that normal, or is the center conductor of the connector damaged? (You can see a bit of those "bendies" on the leaves of the outer conductor, in the picture, too.) My initial guess is the matching, inserter GR-874, after being rotated, and mated, has damaged the insertee?  If so, how does the mated pair maintain 50 ohms?
Best regards and wishes.
Roy

--
Dennis Tillman W7PF
TekScopes Moderator

OT - Fluke Thermometer 2190A goes printing - problem

#158701

OT.

Any one here familiar with this Thermometer seit from fluke?
I Need help.

Config here:  Thermometer 2190A connected to Thermocouple scanner 2300A, this connected to 2030A Printer.

Documents avaiable:

     the Thermometer

in the second document is written that the Thermometer must have the Outputs Option 002 to be used with with the Little Printer 2030A unless a 2300A scanner System is in use.   It is ! But I have no Manual for this 2300A .

  this is the Printer.

Problem:  I need printig from the Thermometer.
In the 2300A is some Little switches OnBoard (mouse piano). Maybe there must be selected anything like a device number??

Thanks for any help.

Greetings from Germany
Martin

Re: oh yeah?

#158700

Pretty sure I'm the only one with four 1S2s, a 1L30, and a Type O on my street!
Maybe I'm just the prince of sampling heads. Come on, a S-42? How cool is that? :) It fits between my S-1, S-2, S-3, S-4, S-5, S-6 and just before my S-52.

Re: 7000 series empty plugin frame $12 shipped

#158699

Those 7A17's sound cool!  I'll take them (email sent).

What other prototyping options are there for 7K series?

Re: FS: scope probes - NOS and used

#158698

hi,

I’d like the Tektronix P3010 s.

Thanks,		larry

Show quoted text

On Aug 10, 2019, at 9:12 PM, Chris Wilkson via Groups.Io <cwilkson@...> wrote:

I'm cleaning out the scope hoard a bit.  I have about 40 extra probes of various make that I'd like to send to a better home.
The basic list is below.   I'm thinking $10/ea for HP/Tek/Yoko and $5/ea otherwise (+ shipping).  Contact me off list if interested in any/all of these.

Thanks,
Chris

=========================================
Yokogawa
=========================================

   700952...3/ea
   --------------
   - for DL1200A scope
   - 150MHz
   - 10X
   - 10M/ (Compensation Range is not known at this time...per Yokogawa)


=========================================
Hewlett Packard
=========================================

   10071A...12/ea
   --------------
   - 150MHz
   - 10X
   - 10M/15pF (9-17pF)
   - for HP54600A scope


   10071B...4/ea
   -------------
   - 150MHz
   - 10X
   - 10M/15pF (9-17pF)
   - for HP54600B scope


=========================================
Tektronix
=========================================

   P3010...2/ea
   - 100MHz
   - 10X
   - 10M/13pF (10-15pF)
   - for TDS3000 series


=========================================
Probe Master
=========================================

   PM2404RA...2/ea
   - 150MHz
   - 10X
   - 10M/ (capacitance unknown)


=========================================
Elenco
=========================================

   P-3E...2/ea
   - switchable 10X-1X attenuation
   - 250MHz......................6MHz
   - 10X.........................1X
   - 10M/13pF (10-30pF)..........1M/56pF


=========================================
Velleman
=========================================

   Probe 150MHz...1/ea
   - switchable 10X-1X attenuation
   - 150MHz......................10MHz
   - 10X.........................1X
   - 10M/12pF (10-35pF)..........1M/46pF


=========================================
AVex Probes
=========================================

   610-10-1-A...15/ea
   - 150MHz
   - 10X
   - 10M/10pF (15-50pF)

   *MANY* accesories...
   probe tips, clips, GND leads, trimmer tools, probe holders, etc...

FS: scope probes - NOS and used

#158697

I'm cleaning out the scope hoard a bit.  I have about 40 extra probes of various make that I'd like to send to a better home.
The basic list is below.   I'm thinking $10/ea for HP/Tek/Yoko and $5/ea otherwise (+ shipping).  Contact me off list if interested in any/all of these.

Thanks,
Chris

=========================================
Yokogawa
=========================================
 
    700952...3/ea
    --------------
    - for DL1200A scope
    - 150MHz
    - 10X
    - 10M/ (Compensation Range is not known at this time...per Yokogawa)
 
 
=========================================
Hewlett Packard
=========================================
 
    10071A...12/ea
    --------------
    - 150MHz
    - 10X
    - 10M/15pF (9-17pF)
    - for HP54600A scope
 
 
    10071B...4/ea
    -------------
    - 150MHz
    - 10X
    - 10M/15pF (9-17pF)
    - for HP54600B scope
 
 
=========================================
Tektronix
=========================================
 
    P3010...2/ea
    - 100MHz
    - 10X
    - 10M/13pF (10-15pF)
    - for TDS3000 series
 
 
=========================================
Probe Master
=========================================
 
    PM2404RA...2/ea
    - 150MHz
    - 10X
    - 10M/ (capacitance unknown)
 
 
=========================================
Elenco
=========================================
 
    P-3E...2/ea
    - switchable 10X-1X attenuation
    - 250MHz......................6MHz
    - 10X.........................1X
    - 10M/13pF (10-30pF)..........1M/56pF
 
 
=========================================
Velleman
=========================================
 
    Probe 150MHz...1/ea
    - switchable 10X-1X attenuation
    - 150MHz......................10MHz
    - 10X.........................1X
    - 10M/12pF (10-35pF)..........1M/46pF
 
 
=========================================
AVex Probes
=========================================
 
    610-10-1-A...15/ea
    - 150MHz
    - 10X
    - 10M/10pF (15-50pF)
 
    *MANY* accesories...
    probe tips, clips, GND leads, trimmer tools, probe holders, etc...

Re: 7000 series empty plugin frame $12 shipped

#158696

Hi John,
A better choice might be the 7A17 Prototyping Plugin. It does have the rear connector. It also has an input BNC, and a complete 150MHz single channel amplifier circuit on it (1Mohm input, 50mV/Div). It also includes a position control (and knob). There is a prototyping area on the circuit board. You can download the manual here if you need more information:

I have two of them available for sale. The price is $15 each. They are complete, working, free of sticker residue, side panels intact, front knob is intact, etc. Shipping in the US was about $15 the last time I checked.

The shipping box I use has room for two plugins and the extra one increases shipping by only $5 so consider taking both. The second one is also complete and working, free of stickers, etc, etc.

Dennis Tillman W7PF

Show quoted text

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of John
Sent: Tuesday, August 06, 2019 2:26 PM
To: [email protected]
Subject: Re: [TekScopes] 7000 series empty plugin frame $12 shipped

I suppose no connectors as they were on the PCB. I am interested but without the male connector it is kind of pointless for what I want.

John
VK2DLP

-- 
Dennis Tillman W7PF
TekScopes Moderator

Re: bounce

#158695

Hi Bert,
TekScopes is not attempting to prune their lists.
There is a possibility your ISP is being blacklisted because of something (like spamming) their customers are doing.
Since this problem appears to be isolated to you alone I think the better way to proceed is to contact your ISP and forward them a copy of one of these messages. They can give you more information on why you cannot receive our posts reliably.

Dennis Tillman W7PF

Show quoted text

-----Original Message-----
Sent: Monday, July 29, 2019 1:57 PM
Subject: [TekScopes] bounce

I have an ongoing problem:
I keep getting a message that my emails from TekScopes are bouncing, reply to this message to fix this.
I do this, get a few messages and then the bouncing message comes up again.
Is this an attempt to prune down the list or is it a glitch in the system.
Thanks,

   Bert




-- 
Dennis Tillman W7PF
TekScopes Moderator

Re: O.T. question on MoVs

#158694

Hi Ancel,
I wouldn't be too concerned about the lack of markings. If Allexpress has been in business for a while they are probably reputable. All the MOVs I have ever come across have little or no markings on them. The markings that were there certainly didn't specify voltage or anything useful.

The test is a simple one if you have a curve tracer. Someone else already described how to do that test. 

If you have a DC power supply that can put out 300V finding out the breakdown voltage is even simpler. Hook the MOV up across the power supply through a 2K to 10K resistor. Put a DVM across the resistor. When you reach the breakdown voltage of the MOV the current in the resistor will increase and the voltage across it will go up. At that point make a note of the voltage on the DVM. That is your MOV Breakdown Voltage.

If you don't have a curve tracer or a DC supply, but you have access to a transformer that will put out 350V, connect the primary of this transformer to a Variac. Connect the MOV to the secondary of the Variac through a current limiting resistor  of 2K to 10K.It should be a 5W or 10W resistor. Connect an AC DVM across the secondary of the transformer so you can monitor this voltage.

Hook your scope across the resistor (ground on one side of the resistor and probe tip on the other). This should be safe to do if you are using a transformer to put out the 350V as I mentioned above. Since you are on the secondary of this transformer there is no ground path back to the power line.

The MOV won't start conducting until it reaches its breakdown voltage so no current will be flowing through the circuit. It is essentially an open circuit until the MOV begins to breakdown. Carefully increase the voltage on the Variac from 0V while you are monitoring the signal on the scope until you see the waveform across the resistor change because the MOV begins to breakdown and draw current. Make a note of the reading on the AC DVM because that is the MOVs breakdown voltage.

Be safe, 270VAC can kill you.

Dennis Tillman W7PF

Show quoted text

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Ancel
Sent: Tuesday, August 06, 2019 3:39 PM
To: [email protected]
Subject: [TekScopes] O.T. question on MoVs

Hi all, 
Somewhat off topic power supply related.
I got some MoVs from aliexpress which I ordered to use in series to protect a 277VAC, 90mA mains supply from high transients.

They ought to be a pair of 270VAC units in series, shorted across the  2 wire AC supply from high transients. 
 07D271 type part. They capacitive coupled  design (2.2uf, 450VAC polypropylene Caps on both lines) allow for 900VAC transient operation without issue.
But ..they shipped unmarked and the supplier is not responding.  So it seems I need to do a test bed to validate their function.
Any advice on the approach?

-- 
Dennis Tillman W7PF
TekScopes Moderator

Re: oh yeah?

#158693

Hi Snapdiode,

That's an interesting claim you're making about being the king of rare and obscure plugins.
Are you talking about the S-Series sampling heads, the 7K series oscilloscope plugins,  TM500/TM5000 series plugins, letter series plugins, or 3 series plugins? 
As you can see Tek made a lot of plugins.

Can you be please be more specific about which plugins you are the king of.

Dennis Tillman W7PF

Show quoted text

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of snapdiode via Groups.Io
Sent: Friday, August 09, 2019 4:38 PM
To: [email protected]
Subject: [TekScopes] oh yeah?

oh yeah.

I am the king of rare and obscure plugins.

Prove me wrong! :)

-- 
Dennis Tillman W7PF
TekScopes Moderator

Re: General Radio 874 Connector, inner conductor "bendies"

#158692

Hi Roy,

The design of the GR-874 is unique (except for its bigger brother) in the electronics industry. It is brilliant design which is why it has lasted so long.
The connectors are hermaphroditic, in other words it has both male and female parts so they can mate to themselves. There is no need for male plugs and female sockets.

To insure the outer leaves are positioned properly with each other it was necessary to place a slight outward bend (or flare) at the end of two opposite outer leaves on each GR-874 connector. This simple mechanical feature insure that the leaves properly position themselves with respect to each other each time you mate two GR-874 connectors. You will notice this also requires you to orient the connectors with a 90 degree turn between them so the leaves with the flair are always opposite leaves with no flair. This wasn't necessary to do for the leaves of the inner conductor. Instead two of the inner leaves are positioned ever so slightly inward closer to the center. This insures the leaves from the other connector (rotated 90 degrees) which our further out from the center will mate perfectly with them. The result is that the outer leaves form a circular pressurized contact with each other and the inner leaves do the same. The circular design with simple mechanical self-alignment insured excellent performance past 7GHz. They are rugged as well, and didn't require any special locking mechanism. GR manufactured numerous adapters, terminators, extenders, power splitters, detectors, slotted lines, tunable filters, etc.  with these connectors on them so it quickly became the standard HF connector in the electronics industry. 

For more information see the article in the GR Experimenter from 1949 which introduced the GR-874:

To see some of the hundreds of things made with GR-874 connectors take a look at this 20 page long excerpt from the GR 1975 catalog:

General Radio made outstanding products. Few companies make products that ae still in use 75 or 100 years after they were designed. The Variac was one of their designs from 1934. They licensed the design to several other companies but the original design was so perfect that the other manufacturers always followed the same design principles. The Variac has been in widespread use for 85 years. I'll bet that at least 50% of the TekScopes members have one and that it gets used. GR-874 connectors aren't quite that old - only 70 years now - but they too are still in widespread use.

Dennis Tillman W7PF

Show quoted text

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Roy Thistle
Sent: Tuesday, August 06, 2019 2:45 PM
To: [email protected]
Subject: [TekScopes] General Radio 874 Connector, inner conductor "bendies"

Hi All:
Apologies, if this has been covered (there are a lot of posts on 874!).. but the picture on Tekwiki of the GR-874 (the one with the plug facing the viewer... so you can see into it)… well that picture shows two of the leaves of the center conductor, bent in at the corners, and so having little "bendies" barbs, or tangs. (You have to see the picture!).
.
My initial question is… Is that normal, or is the center conductor of the connector damaged? (You can see a bit of those "bendies" on the leaves of the outer conductor, in the picture, too.) My initial guess is the matching, inserter GR-874, after being rotated, and mated, has damaged the insertee?  If so, how does the mated pair maintain 50 ohms?
Best regards and wishes.
Roy

-- 
Dennis Tillman W7PF
TekScopes Moderator

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