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

Dale H. Cook
 

On 8/11/2019 4:08 PM, Bruce Hunter wrote:

The 774-series connectors were the predecessors of the 874-type and best described as a banana plug encased with an outer shield.  They were not hermaphroditic.
The Type 774 connectors were used on many GR instruments from its introduction in 1941 until it was supplanted by the Type 874. The 774 was a constant impedance connector which was used for the generator and detector connections of two of the first instruments using it - the Type 821-A Twin-T Impedance Measuring Circuit and the Type 916-A Radio-Frequency Bridge. About 1951 the lower frequency Type 916-AL was introduced with 874 connectors and at that time the 916-A was changed to 874 connectors. Introduced at that time were two other instruments that would not have worked well (if at all) with the 774 connectors - the Type 1601-A V-H-F Bridge (yes, it was hyphenated in the catalog and manual) and the Type 1602-A U-H-F Admittance Meter (ditto).
--
Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
https://plymouthcolony.net/starcity/radios/

Re: 5xx 'Scopes

@0culus
 

On Sun, Aug 11, 2019 at 04:12 PM, Dave Brown wrote:


Definitely IS gone- went there specially to visit it back in 2015 (or was it
2014?) and found it basically all shut up and not much to see thru the windows
or in the yard.
Here's a news item about it-
https://www.santafenewmexican.com/news/local_news/los-alamos-black-hole-is-going-dark/article_a83de44e-0f9d-530c-bd40-1b3b4f6556f5.html

DaveB, NZ
Such a shame...thanks for the note and the confirmation.

Sean

Re: 5xx 'Scopes

Dave Brown
 

Definitely IS gone- went there specially to visit it back in 2015 (or was it 2014?) and found it basically all shut up and not much to see thru the windows or in the yard.
Here's a news item about it-
https://www.santafenewmexican.com/news/local_news/los-alamos-black-hole-is-going-dark/article_a83de44e-0f9d-530c-bd40-1b3b4f6556f5.html

DaveB, NZ

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of sdturne@q.com
Sent: Monday, August 12, 2019 08:57
To: TekScopes@groups.io
Subject: Re: [TekScopes] 5xx 'Scopes

On Sun, Aug 11, 2019 at 01:45 PM, Dave Daniel wrote:


Sean,

I was hoping you lived nearer to one the places where I have lived
(Denver/Boulder area in CO and east coast central FL) so I could
perhaps make some suggestions about where to look. I only know of
Sandia in the Albuquerque area.

DaveD

Dave,

Road trips to Denver area are not out of the question! Suggestions always welcome. There's also Los Alamos...there used to be a great surplus store there that had tons of quality old test equipment...sadly it is gone now last I heard.

Sean

Sean

Re: 465 knob 366-1280-00 (trigger level) wanted

george edmonds
 

Hi

I certainly have the outer knob which is the trigger polarity selector.

George G6HIG

On Sunday, August 11, 2019, 10:40:00 PM GMT+1, Raymond Domp Frank <@Raymond> wrote:

On Sun, Aug 11, 2019 at 09:54 PM, george edmonds wrote:


I should have one if it is the inner knob you want,
AFAIK, it's the outer (ribbed) knob, according to available documentation...

Raymond

Re: Tektronix 577 Regular board capacitor question

Stephen Hanselman
 

We have several sizes of boards that take snap-in caps and replace the old “twist tab” and screw-in caps

Regards,

Stephen Hanselman
Datagate Systems, LLC
3107 North Deer Run Road #24
Carson City, Nevada, 89701
(775) 882-5117 office
(775) 720-6020 mobile
s.hanselman@...
www.datagatesystems.com
a Service Disabled, Veteran Owned Small Business
DISCLAIMER:
This e-mail and any attachments are intended only for use by the addressee(s) named herein and may contain legally privileged and/or proprietary information. If you are not the intended recipient, any dissemination, distribution or copying of this e-mail and any attachments is strictly prohibited. If you have received this e-mail in error, please immediately notify me and permanently delete the original and all copies and printouts of this e-mail and any attachments.

On Aug 11, 2019, at 08:38, DW <wilson2115@...> wrote:

When in doubt just ask the seller selling the adapter board, they will see if they can make a version of this board that accepts snap on capacitors


Re: 465 knob 366-1280-00 (trigger level) wanted

 

On Sun, Aug 11, 2019 at 09:54 PM, george edmonds wrote:


I should have one if it is the inner knob you want,
AFAIK, it's the outer (ribbed) knob, according to available documentation...

Raymond

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

 

On Sun, Aug 11, 2019 at 11:49 AM, gjm45janssen wrote:


The procedure is as follows. Remove the NVRAMs from the Timing Board,
If you have to desolder the NVRAM, make sure that the board carrying it isn't grounded while desoldering, as would be the case if the 'scope is switched off but still plugged in: The earthing of your soldering iron might provide a logic low level to a write (enable) pin, possibly destroying the contents of the chip. In general, beware of transients. Depending on the chip (I haven't looked up the specs), it might be wise to temporarily connect the Vcc pin to the potential that the tip of your soldering iron is at (usually safety earth) so only a logic high level could reach the chip via your soldering iron. Most chips need a logic low level to enable writing.

Raymond

Re: oh yeah?

Jim Ford
 

Ha, I figured somebody in the group would show up Snapdiode sooner or later!Dennis, it looks like the S-42 has a bit of reflections inside it.  The OIG-502 uses an ingenious scheme to avoid generating them at the source; the laser diode is biased such that any current reflections on its input due to imperfections in the termination are below the LD threshold current.  LD physics is such that the current reflections have no effeffect on the optical output.  Voila, reflection-free optical impulses!  I assume a brilliant engineer at Tek came up with that; correct me if I'm wrong.  I had one back in the mid 1990's at Lockheed Aircraft Service Co., housed in a TM502 mainframe (the TM501 was unavailable at the time, IIRC).Jim Ford Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: Dennis Tillman W7PF <@Dennis_Tillman_W7PF> Date: 8/11/19 12:44 AM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] oh yeah? 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: https://groups.io/g/TekScopes/album?id=94144Dennis Tillman W7PF-----Original Message-----Sent: Saturday, August 10, 2019 9:11 PMSubject: 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 W7PFTekScopes Moderator

Re: 5xx 'Scopes

@0culus
 

On Sun, Aug 11, 2019 at 01:45 PM, Dave Daniel wrote:


Sean,

I was hoping you lived nearer to one the places where I have lived
(Denver/Boulder area in CO and east coast central FL) so I could perhaps make
some suggestions about where to look. I only know of Sandia in the Albuquerque
area.

DaveD

Dave,

Road trips to Denver area are not out of the question! Suggestions always welcome. There's also Los Alamos...there used to be a great surplus store there that had tons of quality old test equipment...sadly it is gone now last I heard.

Sean

Sean

Re: 5xx 'Scopes

Dave Daniel
 

Sean,

I was hoping you lived nearer to one the places where I have lived (Denver/Boulder area in CO and east coast central FL) so I could perhaps make some suggestions about where to look. I only know of Sandia in the Albuquerque area.

DaveD

Sent from a small flat thingy

On Aug 11, 2019, at 16:20, sdturne@q.com wrote:

On Sun, Aug 11, 2019 at 01:15 PM, Dave Daniel wrote:


Sean,

Where do you live?

DaveD
Dave,

I'm located in New Mexico, Land of Enchantment.

Sean


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

Reginald Beardsley
 

My 11801 had that problem, but I came to the conclusion that the NVRAM contents can be regenerated via one of the menu options.

I am not about to swear that's true. The manual and the FW are so bad they make the cheapest Chinese DSO look good. But I spent a good bit of time on the topic. The conclusion I came to was that the NVRAM is used to store the results from the "Enhanced Calibration" menu operations if the scope is powered down.

At any rate, I *love* my 11801 even if it is the worst FW I've ever seen. I've got four SD-26 heads for it. And a 2nd unit in CA at my sister's for spares and awaiting shipping when she has time.

I'd be very interested in any information about any information stored in the NVRAM at the time of manufacture and how it is generated and stored.

Have Fun!
Reg

Re: 5xx 'Scopes

ChuckA
 

Sean,

I presently have thirty 500 series scopes that are restored or what I call "good enough to restore someday" and a few more that were bought as donors. I've had good luck on CL and private ads. The best areas I have seen are the Boston MA and Lancaster PA areas. Got my third 555 out of a basement in Boston area had the cart and original plastic cover with it. It was dirty but cleaned up beautifully and only had one resistor open. I did have to remove all 100 tubes to clean pins and sockets.

I really want to find a 519, but so far all the ones I have seen are in Midwest or far west, too far for a drive and I really don't want to ship one. Need one to turn up in the northeast.

You just have to keep looking and make sure you let friends who hit garage sales and the like what you are looking for. A couple of my 575's came that way.

I have over 100 scopes ranging from 1930 lab pieces to a modern digital units. Anything with a CRT is fair game to me.


Chuck

Huh, that is an excellent point. I wouldn't be surprised if there are some around locally due to the reasons mentioned in a prior message. I'll keep my eyes open.

Sean


--
See Early TV at:

www.myvintagetv.com

Re: Is an early 7A26 a keeper?

@0culus
 

On Sun, Aug 11, 2019 at 01:33 PM, Carsten Bormann wrote:


On Aug 11, 2019, at 22:31, Jim Ford <james.ford@...> wrote:



history behind the technology
Yes, but this leaves one curious: why did they change from polyphenylene oxide
to polysulfone?

Grüße, Carsten
I seem to recall reading that polyphenylene oxide is fairly difficult to work with from a manufacturing standpoint. That might have something to do with a switch to polysulfone.

Sean

Re: Is an early 7A26 a keeper?

Carsten Bormann
 

On Aug 11, 2019, at 22:31, Jim Ford <james.ford@...> wrote:

history behind the technology
Yes, but this leaves one curious: why did they change from polyphenylene oxide to polysulfone?

Grüße, Carsten

Re: Is an early 7A26 a keeper?

Jim Ford
 

Great, Hakan!  Always interesting to know the history behind the technology. Jim Ford Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: zenith5106 <hahi@...> Date: 8/11/19 6:00 AM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] Is an early 7A26 a keeper? On Sun, Aug 11, 2019 at 10:46 AM, Dennis Tillman W7PF wrote:> I never noticed this before. I checked mine and I have six that are 20pF and seven that are 22pF.Article in WW from Dec 79://7A16A, 7A26 INPUT CAPACITANCE INCREASEReference: 7A16A S/N B010100 - B099999 (If 050 Kit installed)7A16A S/N Bl00000 & Up7A26 S/N B010100 - B119999 (If 050 Kit installed) 7A26 S/N Bl20000 & UpThe attenuator circuit board material was changed from polyphenylene oxide to polysulfone and the part number changed to 670-2324-05. The differentdielectric constant of the new polysulfone material caused an increase inthe input capacitance of the amplifier.If the 7A16A or 7A26 was manufactured with the new attenuator board or ifany of the below listed product modification kits have been installed, thefollowing change should be made during instrument recalibration:050-0787-01/050-0788-02/050-1056-01/050-1280-00(See Numerical Parts Record and Product Microfiche Mod Summary Index for details.)CALIBRATION CHANGE7A16A Manual,  P/N 070-1378-01On Page 5-5, Step 8, Part a, use A 22pF RC Normalizer in place of the 20pF RC Normalizer.7A26 Manual,  P/N 070-1484-01On Page 5-6, Step 7,  Part a, use A 22pF Normalizer inplace of the 20pF RC Normalizer.The part number of the 22pF RC Normalizer is 067-0755-00.//>  I suspect you will find it was made in 1988 or 1989 just before Tek terminated the product line.Actually 7A26 together with the four remaining 7k products (7104, 7934, 7A29 and 7B15) lived onlonger than that. They were put on Limited Supply in Nov 92./Håkan

Re: 5xx 'Scopes

@0culus
 

On Sun, Aug 11, 2019 at 01:15 PM, Dave Daniel wrote:


Sean,

Where do you live?

DaveD
Dave,

I'm located in New Mexico, Land of Enchantment.

Sean

Re: 5xx 'Scopes

Dave Daniel
 

Sean,

Where do you live?

DaveD

Sent from a small flat thingy

On Aug 11, 2019, at 15:49, sdturne@q.com wrote:

On Sun, Aug 11, 2019 at 12:25 PM, Dennis Tillman W7PF wrote:


Chuck comments reminded me that I forgot to mention one other intriguing
possibility since you have a 7104: Get yourself a 519. This was the original,
and first ever, 1GHz scope Tek made. It make a nice comparison to the 7104.
Since it was produced from 1961 to 1974 it almost overlaps the 7104 which was
introduced in 1978. The contrast between the two instruments shows how
astounding Tektronix advanced oscilloscope technology. In 17 years Tek
revolutionized the capabilities of the oscilloscope from a tiny 2cm x 6cm
single channel barely visible trace into a dual channel 8div x 10div
(0.85cm/div) plug-in lab scope with over 80 plugins you can use with it.

For a few minutes I had a 519 on my bench next to my 7104. And then to my
relief Barrie Gilbert arrived to take the 519. I really didn't have room for
it anywhere so I was glad to see it leave.

Dennis Tillman W7PF
Huh, that is an excellent point. I wouldn't be surprised if there are some around locally due to the reasons mentioned in a prior message. I'll keep my eyes open.

Sean


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

ebrucehunter
 

This discussion of General Radio 874 connectors reminded me of an situation I encountered in the 1960s when my employer acquired a used General Radio VHF signal generator in a nice varnished Mahogany case. Unfortunately it had what turned out to be a General Radio type 774 output connector, instead of an 874, UHF, or type-N.  When I called the GR representative for help, he told me GR still reluctantly made available an adapter from the 774 to the 874 type that was available, but not advertised in the catalog.

The 774-series connectors were the predecessors of the 874-type and best described as a banana plug encased with an outer shield.  They were not hermaphroditic.
The 874 connectors were a quantum leap over their predecessor.  They were very convenient to use, not easily damaged, and showed little wear with use.  And they had a wide range of compatible accessories.  But their undoing began as communications moved to ever higher frequencies. The 874 connectors began to show VSWR and repeatability problems above 6 or 7 GHz or so and were replaced by type-N and SMA connectors for applications above 8 or 10 GHz. 

Nevertheless, for frequencies up to 1 or 2 GHz,  their convenience of use remains unparalleled. 

Bruce Hunter

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

Dale H. Cook
 

On 8/11/2019 1:36 PM, Dennis Tillman W7PF wrote:

The electronics industry lost a great company when they went out of business.
I agree - I have been collecting and using GR instruments for more than 40 years, and collecting and using HP instruments almost as long. The only Tek instruments that I own are my 453 'scope (second version with the FETs but still using pencil HV rectifiers) and my 1503 TDR (as Scotty said in the Star Trek Next Gen episode "Relics" "no A, B, C, or D"). Mine is the unlettered original 1503 with a CRT, not the (frequently failed or failing) LCD screen used in the later, lettered, versions. I have gotten rid of or am getting rid of almost all of my vacuum tube HP instruments (except my working 434A calorimetric power meter and its parts junker) - most of the HP that I now use is from the '70s, which I use in shop and field. The Tek 453 is the shop scope and the 1503 TDR travels with me for field work. The GR instruments used in the field are used little enough that they live at home.
--
Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
https://plymouthcolony.net/starcity/radios/

Re: 465 knob 366-1280-00 (trigger level) wanted

george edmonds
 

Hi

I should have one if it is the inner knob you want, will have to look through my collection of knobs. May be a bit faded as most Tek knobs are by now. Am in the UK

George G6HIG

On Sunday, August 11, 2019, 4:50:09 PM GMT+1, NigelP <nigel-pritchard@...> wrote:

Any chance anybody in the UK has a spare one of these?

I can buy some from the US at a reasonable price on eBay but the postage and import charges at both ends plus UK Post Office "handling" fees make it ridiculous (triples the part cost).

Alternatively if other UK people were interested I could buy 10 from eBay for example and then split the shipping costs????