开云体育

Sorry, the latest batch has sold out. We will have more when we get more chips, but that's hard to predict.

--
Bob Haas

seems to be sold out already!

Wanted to get one,

Jon

W2AEW has an excellent 19 minute video on youtube where he uses a variable bench power supply and an oscilloscope (Tek, of course) to demonstrate and measure characteristics of a tunnel diode; it's probably suitable to confirm basic functionality and charteristics:



Mike Dinolfo N4MWP

Ordered one a minute ago, just because I like to support the museum. ;-) Going to see if I can come up with a nice enclosure for it.

??? Best of the holidays to all.

--
Bruce Lane, ARS KC7GR
kyrrin@...
"Quando Omni Flunkus Moritati" (Red Green)

Another batch of the Museum's popular logo demo boards is available:

Our supply right now is limited by the shortage of chips. Some sellers are quoting 70-week lead times on the processor.
--
Bob Haas

On Mon, Dec 27, 2021 at 05:25 PM, walter shawlee wrote:

I will try and upload it to the files section today, but I can also email it
to anybody that wants it.

Thanks, Walter.
FYI: Also available on Tekwiki:



Raymond

For those looking for a sophisticated and free schematic capture/pcb tool, KiCAD 6.0 just released.
I downloaded it today and tested it (Ubuntu), so far it looks amazing, with huge libraries and a nicer interface.

really worth a visit if you like this kind of software, work in windows, Apple and Linux environments too.



all the best,
walter (walter2 -at- sphere.bc.ca)

The following files have been uploaded to the Files area of the [email protected] group.

• /GE_Tunnel_Diode_Manual.pdf

By: walter shawlee <walter2@...>

Description:
1961 Tunnel diode Manual, with test and app info.

Worked just fine here.

Thomas.

man. 27. des. 2021 kl. 17:06 skrev KB2LMN <acurlik@...>:

--
With Best regards, Thomas S. Knutsen.

Please avoid sending me Word or PowerPoint attachments.

This topic has come up often, and it's clear not everybody has a curve tracer, but many have a need to know if the TD in their gear is good or bad. I just tripped (virtually) over a copy of the 1961 GE tunnel diode manual and application book. something great from 60 years ago.

It has several very good sections on test (including how to build several handy test sets including a simple safe curve tracer) and a LOT of other good data. It's 100 pages, so there's sure to be some tidbits you can use. I will try and upload it to the files section today, but I can also email it to anybody that wants it.

all the best for the new year, we could all really use some improvement,
walter (walter2 -at- sphere.bc.ca)
sphere research corp.

Shows as address invalid

Andrew

On Sun, Dec 26, 2021 at 11:12 PM, Stephen wrote:

I don’t yet know how to interpret these,

Not much to interpret in terms of TDR in your pictures.
Remember, a TDR shows impedance *discontinuities*. If you connect everything nicely terminated, there won't be much to see.

Read your manual for basic operation and setup of your 7S12. Peter H recently correctly mentioned that your vertical sensitivity was set too high. In addition, you need to realize that you have to connect the cable that you want to look at to the S-6's second port and *not* terminate it (at first), or you won't see an echo because there's "no" impedance jump. Set horizontal speed (50ps/div in your pictures) to one that is slow enough to bridge double the propagation time in your cable, or you won't see the echo. Again, Alan Wolke explains what's happening very well and your 7S12 isn't much more than a dedicated 'scope (setup).
Once you get a little further, use a fast horizontal speed to find the "reference plane", i.e. the propagation-time location where the open port of the S-6 sits. The S-52's pulse reflects there because that S-6 port is open, either directly at the port or, preferably, at the end of a short "SMA-save" cable or connector. Any connected cable length will be added to that reference location. It's all in the basic operation info.
But make sure you first understand what's going on in general and thereby, what to look for and what to expect.

Raymond

On Mon, Dec 27, 2021 at 01:17 PM, Raymond Domp Frank wrote:

Alan Wolke (W2AEW)'s videos on Youtube?

This is a very clear, informative and easy to understand video (as always with Alan). It makes you aware of what to expect and how to get there.



Raymond

On Sun, Dec 26, 2021 at 11:12 PM, Stephen wrote:

Experts, what do you say?

Hey Stephen,
Why don't you read up on the basics, indicated and described by several on this Group in this thread. Pointers like general TDR principles, ideas and setups, Alan Wolke (W2AEW)'s videos on Youtube? Very little study of your 7S12 needed at first.

Raymond

Hi all,
Just wanted to remind everyone that the chat server is alive and
kicking. You can join via this invitation link:



After you join you don't need an invitation link.

The link will expire in 7 days, if you need an invitation after that,
drop me a message.

The chat server allows real time text, audio, and video chat. You can
use a dedicated desktop or phone app, or you can use it in the
browser.

You can stream video of your repairs or projects if you want some
feedback or guidance.

Also any manufacturers are allowed beyond Tek and HPAK but those have
separate designated areas.

On Thu, Dec 23, 2021 at 09:09 PM, Siggi wrote:

lithium thionyl chloride

is the cell 3.6v?

I don’t yet know how to interpret these, but I made 4 more pictures that vaguely resemble the ones Miguel uploaded earlier.

Cable is a 6” 50Ω load and SMA to BNC adaptors. Nothing fancy.

Experts, what do you say?

Cheers

/g/TekScopes/album?id=270997

Hi have tried the cable that comes with the nanovna p4 and I only see a little difference of few picoseconds, 4ps

In the photos you can see de difference between a cheap and a microcircuits 50R SMA load.

/g/TekScopes/album?id=271036

I opened up the 7623. As suspected, there are no WIMA caps in there.
I did, however, found the problem. Years ago, I installed the push button illumination mod.
The 2 wires coming from the LM309K disconnected from their terminals during transport out of storage, shorted, and practically fused together.
For now I removed the mod entirely until I find a better way to secure it. The LM309K is likely dead too.

While I was in there, I took the opportunity to disassemble the entire power supply and fan assembly.
I cleaned up the 45yo, 0.5mm layer of soot all over the place. Cleaned, and put new thermal paste on the pass elements, and replace one bad filter cap: C806
It was reading 455mfd instead of the 250mfd it was supposed to be. Odds are it was quite leaky. All the others read fine (so far)
Next step, reassembly without forgetting anything…. So far, it almost looks brand new.

Unfortunately I had to drill out one of the screws that was completely stuck, and had a stripped head, to open it.
And I have no direct replacement with imperial threads…

I understand Peter.
I’ll try to have some more available when I have more time.
Right now I’m fixing my 7623.

Thanks again.