Date   

Re: what's the market for newly produced tunnel diodes?

Bill E
 

And, of course, if you want them to fix old stuff (which we all do), realize that's really a non-market. Setting up fab for a few hundred units that only crazy people like us would buy isn't economically viable.


Re: what's the market for newly produced tunnel diodes?

Chuck Harris <cfharris@...>
 

Conservatively, I would estimate 100.

Look at how many of "us" exist, than notice
that we don't all have things that need their
TD's replaced.

Commercially, the requirement would be essentially
zero. They don't exist in TV's radios, or video
games. They really never took off in that sphere.

The Russians were big in TD's, because they were useful,
and something they could do with their foundries in
the 1960's. TD's didn't demand the cleanliness, or
purity of materials that high speed silicon devices
do.

If you want a foundry to start making TD's again, you
are going to have to create some game altering need
for them to exist... in quantity.

Many universities have mini foundries that they use
to teach practical semiconductor manufacturing techniques.

One such application, I think, is power switching in
solar arrays... or so I am led to believe from the papers
on high power TD's coming from China.

I know that my local university was letting grad students
make LED's, and other crude diodes for educational purposes.

To make TD's, you don't need much more than a chemical hood,
some really nasty chemicals, GE wafers, a way to cut them,
a vacuum deposition chamber... AKA: sputterer, and some stereo
microscopes...

They could have also made TD's.

-Chuck Harris


On Fri, 2 Apr 2021 18:08:35 +0200 "cheater cheater"
<cheater00social@gmail.com> wrote:
Hi all,

there's a few companies producing clones of modern chips for music
synthesis, including CoolAudio (aka Uli Behringer) in China, ALFA RPAR
in Latvia, and SSI. The first two have their own foundries and SSI
supposedly uses Diodes Corp. Would approaching these people to get a
run of tunnel diodes done be a good idea? ALFA specifically seem to be
a smaller company running a tighter ship, but Uli is into a lot of
vintage electronics so he might be interested as well. Obviously for
every company there's some sort of price cutoff point.

Which means one has to ask, how many tunnel diodes could the world use
within the next 10 years? What do you all think?

Cheers


Re: what's the market for newly produced tunnel diodes?

Bill E
 

My opinion, close to zero for the traditional tunnel diode. While they were useful in their time, they just can't do what modern equivalents can do. Not capable of producing much power, and even for tunneling behavior, there is newer tech that is far better, e.g. RTDs (resonant tunneling diodes).
But, while I'm an EE, haven't had any relevant experience with TDs for, hmm, a long time. Which might in itself validate my comment. ::)


Re: Oddly Small Curve Tracer Test Fixtures/Adapters

 

I just had a look at the 571 on TekWiki, and the adapter shown plugged into the top left transistor socket in the first, third, and fourth pictures is EXACTLY what I have in hand.

-- Jeff Dutky


Re: what's the market for newly produced tunnel diodes?

 

In a similar vein, I'm wondering if it is possible to replace the tunnel diodes in a 465/475/475A with something other than a tunnel diode. I thought that there was a recent thread that mentioned replacing tunnel diodes in another instrument (a sampling plug-in?) with Schottky diodes, which got me thinking about this.

-- Jeff Dutky


Re: what's the market for newly produced tunnel diodes?

Stephen
 

I think that would be a very good idea.
I read often that many a unit gets trashed or forgotten because a tunnel diode failure. That’s sad IMHO.


Re: Found some 1N3719 10mA tunnel diodes

 

The 475 uses 1N3718, 10 mA, 25 pF. I am under the impression that the capacitance matters too, based purely on the fact that Tek called it out in the parts list.

-- Jeff Dutky


what's the market for newly produced tunnel diodes?

 

Hi all,

there's a few companies producing clones of modern chips for music
synthesis, including CoolAudio (aka Uli Behringer) in China, ALFA RPAR
in Latvia, and SSI. The first two have their own foundries and SSI
supposedly uses Diodes Corp. Would approaching these people to get a
run of tunnel diodes done be a good idea? ALFA specifically seem to be
a smaller company running a tighter ship, but Uli is into a lot of
vintage electronics so he might be interested as well. Obviously for
every company there's some sort of price cutoff point.

Which means one has to ask, how many tunnel diodes could the world use
within the next 10 years? What do you all think?

Cheers


Re: Found some 1N3719 10mA tunnel diodes

 

The 10mA tunnel diodes are used in the 475 and 485 trigger circuits. The 465 uses 4.7mA diodes.

--
Bob Haas


Re: Odd 453A on ebay UK

Leon Robinson
 

I think your message went about 200 furlongs above his head. 

Leon Robinson  K5JLR

-------- Original message --------
From: "Vintage Test via groups.io" <mel.purcell=icloud.com@groups.io>
Date: 04/02/2021 5:11 AM (GMT-06:00)
To: TekScopes@groups.io
Subject: Re: [TekScopes] Odd 453A on ebay UK

Hey all,

I spotted that was back up again, so sent him this message “
Hi there,

There’s something not quite right with this oscilloscope - if it is a 453A, it should have a 10x8 internal graticule, rather than the 10x6 one as in this one. Has the tube been replaced with a 453 one at some point? Also, it’s a dual trace (electronically switched), rather than a dual-beam (two physical guns in the CRT). The 453A is also fully solid-state, whereas the previous 453 was a mixture of solid-state and Nuvistors - a miniature valve. I’ve attached a pic of a 453A for you to have a look at.

Cheers,
Mel”

However, as yet, no reply and importantly, no alteration to the incorrect description. It just beggars belief that a seller would ignore messages from multiple people, telling him the same thing, but refuses to take it on board! Maybe he’s a flat-earther too! 😜

Cheers,
Mel


--
you can never have enough oscilloscopes, DMMs, valve testers or soldering irons . . .


Re: A6302/P6302 current clamp questions and parts.

Jared Cabot
 

Yeah, I think it's just a case of the rubber becoming a bit compressed and loosing pressure on the cable.
I just reassembled it with a few adjustments and fiddling and it is a lot tighter than it was before, so I think we're on the right track.

Thanks a bunch for all the help! :)


Re: A6302/P6302 current clamp questions and parts.

Albert Otten
 

(continued) I overlooked something. When assembled it's not the cable that is inside the thicker rubber part, but the somewhat wider crimped piece! Maybe you can use some tape or whatever to make it a closer fit.
Albert

On Fri, Apr 2, 2021 at 04:46 PM, Albert Otten wrote:


Encouraged by your picture I dismantled my P6302 plug. It's exactly the same
construction as your plug, except in mine there is no washer at the right side
(in your picture) of the strain relief collar. There is one at the left side.
I have to reconsider the my compression theory.There is considerable free
space around the cable within the thick rubber part. I can slide the metal
bush over that tick part up to the rubber collar without much effort. But it's
hardly possible to slide the long sleeve over the cable. I had to clamp the
cable in a vice and use 4 fingernails behind the collar!
There is nothing to keep the crimped piece fixed in place. It blocks against
the ridge inside the metal bus when you pull the cable out and it bends the
wires when you push in. With the bus screwed in I can see the crimped piece
jiggle together with the cable.
So I guess the only problem is that your cable has too much clearance in the
sleeve.

Albert

On Fri, Apr 2, 2021 at 02:18 PM, Jared Cabot wrote:


Here's a picture of my disassembled plug.
You can see a disk shaped collar piece crimped to the cable just to the left
of the pin assembly.
With the whole thing assembled, the cable can still rotate in the strain
relief boot and that collar can move, leading to flexing of the individual
wires and eventual breakage.
I'm wondering if there is a missing piece in there to clamp that collar, or
some other reason it seems loose.

https://i.imgur.com/Wl1E1vL.jpg


Re: A6302/P6302 current clamp questions and parts.

Albert Otten
 

Encouraged by your picture I dismantled my P6302 plug. It's exactly the same construction as your plug, except in mine there is no washer at the right side (in your picture) of the strain relief collar. There is one at the left side.
I have to reconsider the my compression theory.There is considerable free space around the cable within the thick rubber part. I can slide the metal bush over that tick part up to the rubber collar without much effort. But it's hardly possible to slide the long sleeve over the cable. I had to clamp the cable in a vice and use 4 fingernails behind the collar!
There is nothing to keep the crimped piece fixed in place. It blocks against the ridge inside the metal bus when you pull the cable out and it bends the wires when you push in. With the bus screwed in I can see the crimped piece jiggle together with the cable.
So I guess the only problem is that your cable has too much clearance in the sleeve.

Albert

On Fri, Apr 2, 2021 at 02:18 PM, Jared Cabot wrote:


Here's a picture of my disassembled plug.
You can see a disk shaped collar piece crimped to the cable just to the left
of the pin assembly.
With the whole thing assembled, the cable can still rotate in the strain
relief boot and that collar can move, leading to flexing of the individual
wires and eventual breakage.
I'm wondering if there is a missing piece in there to clamp that collar, or
some other reason it seems loose.

https://i.imgur.com/Wl1E1vL.jpg


Found some 1N3719 10mA tunnel diodes

 

I am not sure if these are useful in any Tek trigger circuits (I seem to recall the currents are usually lower) , but I came across 3 new factory sealed, tiny gold tunnel diodes, GE 1N3719. The data says 10mA peak point current, so I suppose that is the key parameter. In any case, no use to me, can sell and ship them very cheaply to anybody that can use them. have a good and safe easter weekend!

please email me off list,
all the best,
walter (walter2 -at- sphere.bc.ca)
sphere research corp.
lots of tek goodies at: https://www.sphere.bc.ca/test/stuffday.html#tekfans


Re: 492AP screen dump

Attilio
 

Good day everyone, I need your help to interface the PC to the 492P through the Prologix and using the HP7470A emulator program.
I connected the various components (PC with USB port, Prologix to the GPIB port of the 492P) and turned on both the PC and the 492 P. The settings of the GPIB switches on the 492P are for address 3, EOI, TALK and LISTEN to logic 0 (?).
By pressing the "REMOTE" button on the 492 P, the display shows "492 P VER 1.6 BUSADD 03". The Prologix has no switches and has two LEDs, the "LISTEN" LED lights up (the "TALK" LED is off).
The "ADDRESSED" led on the 492 P turns on and the controls on the front are blocked. If I launch the HP7470A emulator program and select acquiring from tektronix 49x with address 3, the LED of the "REMOTE" button on the 492 P lights up but the program freezes, does not respond and displays nothing.
I also tried to run the GPIB configurator program that sees me the COMM 3 port (USB connected to the Prologix), but I don't know how to set the parameters.

--Cheers
Attilio


575 step amplifier

Stockfish
 

Hi,
I'm a new member of this very interesting discussion group. I'm living in France and I have some old Tektronix devices. The last I got is a 575 curve tracer.

It's in very good cosmetic condition but it can't give the family curves for a transistor under test.
Only one curve is displayed. It seems that the problem is in the step amplifier.

The step generator is ok because the step waveform is correct on the input of the step amplifier but there is no step on its output.

I thought that the Ge transistors 2N2148 and 2N277 were probably out of work.
So, I have changed these transistors with 2 other Ge power transistors but they instantaneouly burned.

The voltages given by the power supply are ok.

Has someone already encountered this problem ?

Many thanks.


Re: A6302/P6302 current clamp questions and parts.

Jared Cabot
 

Here's a picture of my disassembled plug.
You can see a disk shaped collar piece crimped to the cable just to the left of the pin assembly.
With the whole thing assembled, the cable can still rotate in the strain relief boot and that collar can move, leading to flexing of the individual wires and eventual breakage.
I'm wondering if there is a missing piece in there to clamp that collar, or some other reason it seems loose.

https://i.imgur.com/Wl1E1vL.jpg


Re: Odd 453A on ebay UK

Vintage Test
 

Hey all,

I spotted that was back up again, so sent him this message “
Hi there,

There’s something not quite right with this oscilloscope - if it is a 453A, it should have a 10x8 internal graticule, rather than the 10x6 one as in this one. Has the tube been replaced with a 453 one at some point? Also, it’s a dual trace (electronically switched), rather than a dual-beam (two physical guns in the CRT). The 453A is also fully solid-state, whereas the previous 453 was a mixture of solid-state and Nuvistors - a miniature valve. I’ve attached a pic of a 453A for you to have a look at.

Cheers,
Mel”

However, as yet, no reply and importantly, no alteration to the incorrect description. It just beggars belief that a seller would ignore messages from multiple people, telling him the same thing, but refuses to take it on board! Maybe he’s a flat-earther too! 😜

Cheers,
Mel


--
you can never have enough oscilloscopes, DMMs, valve testers or soldering irons . . .


Re: Oddly Small Curve Tracer Test Fixtures/Adapters

Dave Casey
 

At least one of those sounds like the one that came on the Tek 571 (made in
Holland).

Dave Casey

On Thu, Apr 1, 2021 at 7:59 PM Jeff Dutky <jeff.dutky@gmail.com> wrote:

I recently obtained a 7CT1N curve tracer plug-in to use in my (still
non-functional) 7623A (or in my also non-functional 7603). I had planned to
build a custom test fixture with multiple, paired sockets, and a switch to
allow comparison of devices, but then I saw a couple of test fixtures for
relatively good prices (each below $50) on eBay, and ordered several of
them.

Two of the fixtures (an 013-069 and an 013-070) are obviously intended
for use with the 7CT1N as they have only three banana plugs, arranged in a
row, and spaced correctly to plug in to the binding posts on the 7CT1N, but
three others, which came only as populated circuit boards are,
surprisingly, about 30% narrower than the first two, and the banana plugs
are too close together to fit either the 7CT1N or any of the 57x curve
tracers.

The boards bear silk screening that indicates they were made by Tektronix
in Holland in 1989. One of them bears a full Tek part number (369-0769-00,
which I have not been able to find on TekWiki, or in a general web search),
while the other two have a part number with XXXX in the middle position.
The one that bears a full part number is populated with three sockets, one
a linear set of three pin sockets, the other two are three pin sockets for
two different sized can devices (like TO-18 and TO-39/TO-52).

I have uploaded pictures of the adapters to the photos section in an album
titled "Small Curve Tracer Text Fixtures"

Was there another kind of curve tracer made by Tek in the late 80's that
used a closer spacing of the binding posts/banana sockets?

-- Jeff Dutky






Re: Tek 2430 Works Fine for 15mins Then Freezes

Steven Bender
 

Hi John,

I have a 7603 that is a mainframe scope which did something similar, 15 to 30 minutes then frozen. I also have some 2445’s that do need caps and/or possibly diodes.

The 7603 had 2N3055 or similar TO-3 pass transistors, due to decades of heat, solder on their B and E pins became faulty, needed solder removal and resoldering.

On a 24xx first look for silver cased 100 uF. / 25 vdc low volt caps, they are a known problem in the 2445, check the associated 3A shottkey diodes on "diode test". Look for any darkened “Burn Marks” on PS circuit board.

I have some non-tek units from the 1980’s which gave lots of yellow/orange drop tantalum bypass caps, across Op Amp voltage lines that are usually +/-15 volt or +/-18 volt lines and elsewhere - tantalums, that had impurities in their manufacture, which 2, 3, or 4 decades later will either glow, burn black, or smoke, damaging nearby trimmers, or other parts, typical and definite signs of a failure, partial short, or dead short. As such, for 16 volt, 20 volt, or 25 volt tantalum parts, replace with similar value 35 volt parts, usually cures it. While electrolytic have also improved over the decades, to change to an electrolytic, in general triple the value, and expect to replace again in twenty years :-).

Steven

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