Date   

Re: A Vacuum Tube Curve Tracer for all Tek Semiconductor Curve Trace

Dave Brown <tractorb@...>
 

Dennis
How many of the 7 and 9 pin plugs do you need? Are you looking for a
significant number?
73
Dave, ZL3FJ

-----Original Message-----
From: TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com]
Sent: Monday, March 27, 2017 3:46 PM
To: TekScopes@yahoogroups.com
Subject: RE: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek
Semiconductor Curve Trace

Hi Bill,
In my case I needed tube PLUGS that would plug into a tube SOCKET. That is
my problem.

I am well aware of Tubesandmore. They certainly have a nice selection of 4
pin, 5 pin, 7 pin, 8 pin , and 9 pin tube SOCKETS. Unfortunately other than
8 pin tube PLUGS they, or anyone else for that matter, do not sell 7 pin
miniature tube PLUGS or 9 pin miniature PLUGS. Since 7 pin miniature tubes
and 9 pin miniature tubes have their pins coming right out of the glass
envelope this will make it very hard to get what I need by smashing spent
tubes to try and get an intact set of pins around the base of the tube.

As John Gord pointed out one way to find some of these is by searching for
socket savers. They, too, are scarce these days. Not many people are
designing things with tubes. There was a 9 pin and a 7 pin socket saver
auction on Ebay and I bid $28 for them but someone outbid me. I have no way
to know how high that person's ultimate bid might have been.

Dennis Tillman, W7PF

-----Original Message-----
Sent: Sunday, March 26, 2017 5:08 PM
Subject: Re: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek
Semiconductor Curve Trace

Dennis and all,
Has everyone been overlooking the best source for tubes and related
hardware?

https://www.tubesandmore.com/products/tube_accessories
Bill
KB3DKS

-----Original Message-----
From: 'Dennis Tillman' dennis@ridesoft.com [TekScopes]
<TekScopes@yahoogroups.com>
Sent: Wed, Mar 22, 2017 10:06 am

Hi John,
Thanks for the suggestion. I know I kept coming across octal socket savers
all the time but I never saw a 7 pin or 9 pin socket saver. I will give that
a try.
Dennis Tillman W7PF

-----Original Message-----
Sent: Tuesday, March 21, 2017 5:06 PM
Subject: RE: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek
Semiconductor Curve Trace

Try a Google search for "7 pin socket saver". I got some hits. 9 pin
socket savers seem to be more common. It looks like at least some of the
socket savers could be disassembled.
--John Gord
------------------------------------
Posted by: Doxemf <doxemf@aol.com>
------------------------------------




------------------------------------
Posted by: "Dennis Tillman" <dennis@ridesoft.com>
------------------------------------


------------------------------------

Yahoo Groups Links


Re: A Vacuum Tube Curve Tracer for all Tek Semiconductor Curve Trace

 

stuff that disappears does so for a reason. Maybe you just simply
don't get tubes with that base that are any interesting at all. No
point trying to accumulate stuff that's boring other than it has a
specific pinout.

On Mon, Mar 27, 2017 at 6:56 AM, 'Dennis Tillman' dennis@ridesoft.com
[TekScopes] <TekScopes@yahoogroups.com> wrote:
Hi Cheater,
In a pinch I did make a 9 pin plug using 0.040" bus bar pushed into an existing 9 pin socket, with a piece of PVC tubing around it, and I potted the entire thing. What you get is crude, and it takes a fair amount of time to do this. So this is hardly a reasonable solution except in a pinch. I was hoping for something that was much more professional and took far less time. I don't mind paying $10 for a plug that I can order from somewhere.

Some of the tube stuff seems to have disappeared, and other stuff seems to be doing just fine. I haven't figured out which stuff is rare that I should jump at them whenever they show up versus the stuff that is still very common and still being produced. I'm new to the whole tube world. Last time I touched a vacuum tube was 40+ years ago until very recently.

Dennis Tillman W7PF

-----Original Message-----
Sent: Sunday, March 26, 2017 9:29 PM
Subject: Re: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek Semiconductor Curve Trace

Am I missing something... why not just take a bare FR board and drill some holes in it.. use two boards for rigidity... and pot the whole job?

On Mon, Mar 27, 2017 at 5:42 AM, Doxemf doxemf@aol.com [TekScopes] <TekScopes@yahoogroups.com> wrote:
Dennis,
They have the 9 pin Socket Savers. I did not see any 7 pin. Quite awhile ago there were some cheap car stereo players, maybe eve 8 tracks, I forget, I serviced them once. Anyway, they used a 9 pin male/female connector. I think that the old Calrad or similar brand offered the cable sets. Fair Radio used to have some as well. Someone with a 3D printer could probably spit a bunch out that way. Just have to provide the pins.
Bill, KB3DKS

-----Original Message-----
From: 'Dennis Tillman' dennis@ridesoft.com [TekScopes]
Sent: Sun, Mar 26, 2017 10:46 pm

Hi Bill,
In my case I needed tube PLUGS that would plug into a tube SOCKET.
That is my problem.

I am well aware of Tubesandmore. They certainly have a nice selection
of 4 pin, 5 pin, 7 pin, 8 pin , and 9 pin tube SOCKETS. Unfortunately
other than
8 pin tube PLUGS they, or anyone else for that matter, do not sell 7
pin miniature tube PLUGS or 9 pin miniature PLUGS. Since 7 pin
miniature tubes and 9 pin miniature tubes have their pins coming right
out of the glass envelope this will make it very hard to get what I
need by smashing spent tubes to try and get an intact set of pins around the base of the tube.

As John Gord pointed out one way to find some of these is by searching
for socket savers. They, too, are scarce these days. Not many people
are designing things with tubes. There was a 9 pin and a 7 pin socket
saver auction on Ebay and I bid $28 for them but someone outbid me. I
have no way to know how high that person's ultimate bid might have been.

Dennis Tillman, W7PF

-----Original Message-----
Sent: Sunday, March 26, 2017 5:08 PM
Subject: Re: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek
Semiconductor Curve Trace

Dennis and all,
Has everyone been overlooking the best source for tubes and related
hardware?

https://www.tubesandmore.com/products/tube_accessories
Bill
KB3DKS
------------------------------------
Posted by: Doxemf <doxemf@aol.com>
------------------------------------
------------------------------------
Posted by: cheater00 cheater00 <cheater00@gmail.com>
------------------------------------




------------------------------------
Posted by: "Dennis Tillman" <dennis@ridesoft.com>
------------------------------------


------------------------------------

Yahoo Groups Links



Re: A Vacuum Tube Curve Tracer for all Tek Semiconductor Curve Trace

 

Hi Cheater,
In a pinch I did make a 9 pin plug using 0.040" bus bar pushed into an existing 9 pin socket, with a piece of PVC tubing around it, and I potted the entire thing. What you get is crude, and it takes a fair amount of time to do this. So this is hardly a reasonable solution except in a pinch. I was hoping for something that was much more professional and took far less time. I don't mind paying $10 for a plug that I can order from somewhere.

Some of the tube stuff seems to have disappeared, and other stuff seems to be doing just fine. I haven't figured out which stuff is rare that I should jump at them whenever they show up versus the stuff that is still very common and still being produced. I'm new to the whole tube world. Last time I touched a vacuum tube was 40+ years ago until very recently.

Dennis Tillman W7PF

-----Original Message-----
Sent: Sunday, March 26, 2017 9:29 PM
Subject: Re: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek Semiconductor Curve Trace

Am I missing something... why not just take a bare FR board and drill some holes in it.. use two boards for rigidity... and pot the whole job?

On Mon, Mar 27, 2017 at 5:42 AM, Doxemf doxemf@aol.com [TekScopes] <TekScopes@yahoogroups.com> wrote:
Dennis,
They have the 9 pin Socket Savers. I did not see any 7 pin. Quite awhile ago there were some cheap car stereo players, maybe eve 8 tracks, I forget, I serviced them once. Anyway, they used a 9 pin male/female connector. I think that the old Calrad or similar brand offered the cable sets. Fair Radio used to have some as well. Someone with a 3D printer could probably spit a bunch out that way. Just have to provide the pins.
Bill, KB3DKS

-----Original Message-----
From: 'Dennis Tillman' dennis@ridesoft.com [TekScopes]
Sent: Sun, Mar 26, 2017 10:46 pm

Hi Bill,
In my case I needed tube PLUGS that would plug into a tube SOCKET.
That is my problem.

I am well aware of Tubesandmore. They certainly have a nice selection
of 4 pin, 5 pin, 7 pin, 8 pin , and 9 pin tube SOCKETS. Unfortunately
other than
8 pin tube PLUGS they, or anyone else for that matter, do not sell 7
pin miniature tube PLUGS or 9 pin miniature PLUGS. Since 7 pin
miniature tubes and 9 pin miniature tubes have their pins coming right
out of the glass envelope this will make it very hard to get what I
need by smashing spent tubes to try and get an intact set of pins around the base of the tube.

As John Gord pointed out one way to find some of these is by searching
for socket savers. They, too, are scarce these days. Not many people
are designing things with tubes. There was a 9 pin and a 7 pin socket
saver auction on Ebay and I bid $28 for them but someone outbid me. I
have no way to know how high that person's ultimate bid might have been.

Dennis Tillman, W7PF

-----Original Message-----
Sent: Sunday, March 26, 2017 5:08 PM
Subject: Re: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek
Semiconductor Curve Trace

Dennis and all,
Has everyone been overlooking the best source for tubes and related
hardware?

https://www.tubesandmore.com/products/tube_accessories
Bill
KB3DKS
------------------------------------
Posted by: Doxemf <doxemf@aol.com>
------------------------------------
------------------------------------
Posted by: cheater00 cheater00 <cheater00@gmail.com>
------------------------------------


Re: A Vacuum Tube Curve Tracer for all Tek Semiconductor Curve Trace

 

Am I missing something... why not just take a bare FR board and drill
some holes in it.. use two boards for rigidity... and pot the whole
job?

On Mon, Mar 27, 2017 at 5:42 AM, Doxemf doxemf@aol.com [TekScopes]
<TekScopes@yahoogroups.com> wrote:
Dennis,
They have the 9 pin Socket Savers. I did not see any 7 pin. Quite awhile ago there were some cheap car stereo players, maybe eve 8 tracks, I forget, I serviced them once. Anyway, they used a 9 pin male/female connector. I think that the old Calrad or similar brand offered the cable sets. Fair Radio used to have some as well. Someone with a 3D printer could probably spit a bunch out that way. Just have to provide the pins.
Bill, KB3DKS



-----Original Message-----
From: 'Dennis Tillman' dennis@ridesoft.com [TekScopes] <TekScopes@yahoogroups.com>
To: TekScopes <TekScopes@yahoogroups.com>
Sent: Sun, Mar 26, 2017 10:46 pm
Subject: RE: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek Semiconductor Curve Trace

Hi Bill,
In my case I needed tube PLUGS that would plug into a tube SOCKET. That is
my problem.

I am well aware of Tubesandmore. They certainly have a nice selection of 4
pin, 5 pin, 7 pin, 8 pin , and 9 pin tube SOCKETS. Unfortunately other than
8 pin tube PLUGS they, or anyone else for that matter, do not sell 7 pin
miniature tube PLUGS or 9 pin miniature PLUGS. Since 7 pin miniature tubes
and 9 pin miniature tubes have their pins coming right out of the glass
envelope this will make it very hard to get what I need by smashing spent
tubes to try and get an intact set of pins around the base of the tube.

As John Gord pointed out one way to find some of these is by searching for
socket savers. They, too, are scarce these days. Not many people are
designing things with tubes. There was a 9 pin and a 7 pin socket saver
auction on Ebay and I bid $28 for them but someone outbid me. I have no way
to know how high that person's ultimate bid might have been.

Dennis Tillman, W7PF

-----Original Message-----
Sent: Sunday, March 26, 2017 5:08 PM
Subject: Re: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek
Semiconductor Curve Trace

Dennis and all,
Has everyone been overlooking the best source for tubes and related
hardware?

https://www.tubesandmore.com/products/tube_accessories
Bill
KB3DKS





[Non-text portions of this message have been removed]



------------------------------------
Posted by: Doxemf <doxemf@aol.com>
------------------------------------


------------------------------------

Yahoo Groups Links



Re: A Vacuum Tube Curve Tracer for all Tek Semiconductor Curve Trace

Bill (Doc) Courtright
 

Dennis,
They have the 9 pin Socket Savers. I did not see any 7 pin. Quite awhile ago there were some cheap car stereo players, maybe eve 8 tracks, I forget, I serviced them once. Anyway, they used a 9 pin male/female connector. I think that the old Calrad or similar brand offered the cable sets. Fair Radio used to have some as well. Someone with a 3D printer could probably spit a bunch out that way. Just have to provide the pins.
Bill, KB3DKS

-----Original Message-----
From: 'Dennis Tillman' dennis@ridesoft.com [TekScopes] <TekScopes@yahoogroups.com>
To: TekScopes <TekScopes@yahoogroups.com>
Sent: Sun, Mar 26, 2017 10:46 pm
Subject: RE: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek Semiconductor Curve Trace

Hi Bill,
In my case I needed tube PLUGS that would plug into a tube SOCKET. That is
my problem.

I am well aware of Tubesandmore. They certainly have a nice selection of 4
pin, 5 pin, 7 pin, 8 pin , and 9 pin tube SOCKETS. Unfortunately other than
8 pin tube PLUGS they, or anyone else for that matter, do not sell 7 pin
miniature tube PLUGS or 9 pin miniature PLUGS. Since 7 pin miniature tubes
and 9 pin miniature tubes have their pins coming right out of the glass
envelope this will make it very hard to get what I need by smashing spent
tubes to try and get an intact set of pins around the base of the tube.

As John Gord pointed out one way to find some of these is by searching for
socket savers. They, too, are scarce these days. Not many people are
designing things with tubes. There was a 9 pin and a 7 pin socket saver
auction on Ebay and I bid $28 for them but someone outbid me. I have no way
to know how high that person's ultimate bid might have been.

Dennis Tillman, W7PF

-----Original Message-----
Sent: Sunday, March 26, 2017 5:08 PM
Subject: Re: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek
Semiconductor Curve Trace

Dennis and all,
Has everyone been overlooking the best source for tubes and related
hardware?

https://www.tubesandmore.com/products/tube_accessories
Bill
KB3DKS


Re: 7912AD Repair

Bill Higdon
 

Should have been down not sown
Bill


Re: A Vacuum Tube Curve Tracer for all Tek Semiconductor Curve Trace

 

Hi Bill,
In my case I needed tube PLUGS that would plug into a tube SOCKET. That is
my problem.

I am well aware of Tubesandmore. They certainly have a nice selection of 4
pin, 5 pin, 7 pin, 8 pin , and 9 pin tube SOCKETS. Unfortunately other than
8 pin tube PLUGS they, or anyone else for that matter, do not sell 7 pin
miniature tube PLUGS or 9 pin miniature PLUGS. Since 7 pin miniature tubes
and 9 pin miniature tubes have their pins coming right out of the glass
envelope this will make it very hard to get what I need by smashing spent
tubes to try and get an intact set of pins around the base of the tube.

As John Gord pointed out one way to find some of these is by searching for
socket savers. They, too, are scarce these days. Not many people are
designing things with tubes. There was a 9 pin and a 7 pin socket saver
auction on Ebay and I bid $28 for them but someone outbid me. I have no way
to know how high that person's ultimate bid might have been.

Dennis Tillman, W7PF

-----Original Message-----
Sent: Sunday, March 26, 2017 5:08 PM
Subject: Re: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek
Semiconductor Curve Trace

Dennis and all,
Has everyone been overlooking the best source for tubes and related
hardware?

https://www.tubesandmore.com/products/tube_accessories
Bill
KB3DKS

-----Original Message-----
From: 'Dennis Tillman' dennis@ridesoft.com [TekScopes]
<TekScopes@yahoogroups.com>
Sent: Wed, Mar 22, 2017 10:06 am

Hi John,
Thanks for the suggestion. I know I kept coming across octal socket savers
all the time but I never saw a 7 pin or 9 pin socket saver. I will give that
a try.
Dennis Tillman W7PF

-----Original Message-----
Sent: Tuesday, March 21, 2017 5:06 PM
Subject: RE: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek
Semiconductor Curve Trace

Try a Google search for "7 pin socket saver". I got some hits. 9 pin
socket savers seem to be more common. It looks like at least some of the
socket savers could be disassembled.
--John Gord
------------------------------------
Posted by: Doxemf <doxemf@aol.com>
------------------------------------


CORRECTED POST : Tek 2445 vs Tek 2430A (Tek 2435A)

 

I have 3 Tek 2445 scopes and one Tek 2430A scope. While idly bumming around eBay, I noticed that it seemed to me the 2445s were less common and on average more expensive than the 2430As. Seeing as how the 2430A is a DSO and the 2445 is analog I would have expected the opposite. Am I wrong in this thinking or am I missing something?


Re: A Vacuum Tube Curve Tracer for all Tek Semiconductor Curve Trace

Bill (Doc) Courtright
 

Dennis and all,
Has everyone been overlooking the best source for tubes and related hardware?

https://www.tubesandmore.com/products/tube_accessories
Bill
KB3DKS

-----Original Message-----
From: 'Dennis Tillman' dennis@ridesoft.com [TekScopes] <TekScopes@yahoogroups.com>
To: TekScopes <TekScopes@yahoogroups.com>
Sent: Wed, Mar 22, 2017 10:06 am
Subject: RE: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek Semiconductor Curve Trace

Hi John,
Thanks for the suggestion. I know I kept coming across octal socket savers
all the time but I never saw a 7 pin or 9 pin socket saver. I will give that
a try.
Dennis Tillman W7PF

-----Original Message-----
Sent: Tuesday, March 21, 2017 5:06 PM
Subject: RE: [TekScopes] Re: A Vacuum Tube Curve Tracer for all Tek
Semiconductor Curve Trace

Try a Google search for "7 pin socket saver". I got some hits. 9 pin
socket savers seem to be more common. It looks like at least some of the
socket savers could be disassembled.
--John Gord


Re: Tek 2445 vs Tek 2435A

Chuck Harris
 

The 150MHz 2445 came out concurrent with the 300MHz 2465,
costing $3250 vs the 2465's $4750.

Double the performance, and only a third more in price.

More the wonder is why any sold at all?

-Chuck Harris

houdatto@gmail.com [TekScopes] wrote:

I have 3 Tek 2445 scopes and one Tek 2435A scope. While idly bumming around eBay,
I noticed that it seemed to me the 2445s were less common and on average more
expensive than the 2435As. Seeing as how the 2435A is a DSO and the 2445 is analog
I would have expected the opposite. Am I wrong in this thinking or am I missing
something?


Re: 7912AD Repair

Bill Higdon
 

The Little Mountain part/Annex of Hill AFB has an interesting history. originally it was a specially built wind tunnel for testing the Ramjet engines for the Bomarc. After that program shut sown it was dormant for a period of time until the Air Force realized they needed to move the High energy X Ray system to some place where the particle beams didn't have a chance of hitting people like they did when they were on Hill AFB proper. So they moved them to the Little Mountain facility. They're on the west side of the the mountain, follow the road past Moulding and sons landfill.


Re: Intro & Tek 2235 - Momentary trace only with dim bulb tester

A Rob
 

Voltages at Q114 & Q115 stay exactly the same when switching between ch1 & ch2.

I have double checked voltages and there is a slight difference to what I'd previously reported:

U130 Pin 13 1.97 Volts Selected
U130 Pin 13 2.79 Volts Not Selected

U130 Pin 9 2.49 Volts Selected
U130 Pin 9 2.78 Volts Not Selected

U130 Pin 7 0.00 Volts Selected
U130 Pin 7 -0.01 Volts Not Selected

U130 Pin 14 0.74 Volts Selected
U130 Pin 14 -0.59 Volts Not Selected

R143 is reading as 98.62ohm in circuit
L143 is reading 0.01ohm in circuit


Re: 2465 Vertical Gain

Chuck Harris
 

The 2465B stores all of the offsets, and gain changes necessary
to make the scope in calibration in the NVRAM that is on the A5
board. The only adjustment pots are in places where a resistor
must be a resistor, not a computer generated voltage.

It takes a full vertical recalibration to fix your problem.

-Chuck Harris


greg_knox@bellsouth.net [TekScopes] wrote:

The CH 2 vertical gain on my 2465b is a few percent off, relative to the CH 1
gain, which is right on. Is there an adjustment pot for this, or do I have to go
through the whole calibration procedure to fix it? The scope passes all the power
up self tests and works beautifully otherwise. Thanks.




Re: 7912AD Repair

Roger Evans
 

Chris,

The digitised output only appears on the XYZ connectors, I use a 485 in XY mode and found that the Z connection did not add anything useful.

When I press the digital button. Tha analogue monitor goes black and two seconds later the digitised signal appears on the XY monitor. Subsequently pressing the digital button gives a new digitised trace immediately. The manual says the first two second delay is to allow voltages to stabilise.

The same thing happens when you give commands via GPIB. I have a home made USB to GPIB interface and can store data and view images on a PC. Apart from the elation of getting the 7912 to work there is now the question of what to do with the enormous box in the corner!

Roget


Re: 7912AD Repair

cmjones01
 

On Sun, Mar 26, 2017 at 9:04 PM, very_fuzzy_logic@yahoo.com [TekScopes] <
TekScopes@yahoogroups.com> wrote:



Chris,
The fastest sweep speeds need the x10 magnifier so you will have an
apparently wide scan. On the 7B90P there is a 'mag' led that comes on.

It turned out that the crazy magnification was because the X read scan
amplifier wasn't working due to, you've guessed it, yet another
short-circuit tantalum on the -15V rail which had taken out its 10R
decoupling resistor. I replaced both and the remaining tants on that board,
and now I have a proper scan, with graticule and waveform!


The focus control on the front panel has little effect on my 7912AD, the
spot blooms very quickly if the brightness is too high but is sharp at the
lowest usable intensity. The Z axis amplifier is driven differently for the
graticule and the sweep and mine struggles to show sharp trace and
graticule at the same time. For serious use you would digitise the
graticule separately, I believe the software is supposed to calculate the
centroid of each graticule spot.

Now that both scan amplifiers are working, my focus control behaves in a
very similar way: when it's not optimally set, the trace and graticule look
a bit dim and ill-defined rather than fuzzy in the way they would on a
standard analogue scope. I can get a sharp trace and graticule with the
focus control at mid position and experience the blooming if I crank up
either intensity too much. What I was seeing before was *all* blooming
because I had no X read scan!

Sounds like you should have a working 7912 soon!
Yes, I think we're almost there. I'm not sure if the digitiser is working
properly. I have a monitor connected to the linear TV out (the binary one
also works but is harder to use for adjusting everything). I can see the
trace and graticule. There seems to be some hum on the trace but that could
be due to an earth loop and having the cases off everything. When I press
the 'digital' button the screen goes white. I read in the manual this
morning that a digitisation takes 2 seconds, and so I should probably be
more patient: presumably I should see the frozen waveform on the monitor
after that. I haven't tried the XYZ output yet.

I do have a full 'doorstep' set of paper manuals, thanks to a fortuitous
visit to Manuals Plus a week or so before they closed down. They're
labelled 'Hill AFB - Little Mountain', so I bet they could tell a few
stories.

Chris


Re: 7912AD Repair

Roger Evans
 

Chris,
The fastest sweep speeds need the x10 magnifier so you will have an apparently wide scan. On the 7B90P there is a 'mag' led that comes on.

The graticule should show 10 x 8 equal squares so that would confirm that the read scan size is correct.

The focus control on the front panel has little effect on my 7912AD, the spot blooms very quickly if the brightness is too high but is sharp at the lowest usable intensity. The Z axis amplifier is driven differently for the graticule and the sweep and mine struggles to show sharp trace and graticule at the same time. For serious use you would digitise the graticule separately, I believe the software is supposed to calculate the centroid of each graticule spot.

The required intensity for a good trace varies a lot with sweep speed and rep rate. Also the cpu will limit the maximum Z axis drive at lower sweep speeds, I would try making small adjustments to the Grid Bias to get good results for a repetitive 10ns/div sweep with no more than one turn of the write intensity pot. You should then be able to digitise single sweeps with the intensity turned right up. There is a formal Z axis calibration but I have slightly low output from the Z amplifier so I opted for the trial and error approach. I would strongly recommend turning the intensity right down before you turn the 7912 on as a matter of habit.

Sounds like you should have a working 7912 soon!

Regards,

Roger


Last minute stuff requests while dennis is here

 

Dennis and Aris are up here at sphere this weekend, he is bringing back the little meters, and the 570 meter, any other requests? we need to know in the next few hours.

I also have clean working 465M vertical/horizontals for $25 each, 11K , 5K, 2/3 series and other plug ins. this is a chance to get them down there with no freight. bad plug ins are $5/$10.

You can email me off list at walter2 -at- sphere.bc.ca or call us at 1-250-769-1834. we will be out for breakfast from 10 to 11am.

-walter
sphere research corp.


Re: Meanwhile in Austria

Fabio Trevisan
 

Wow... That's cool!!!!... And the way he made for the shapes to "sing" as
well! Awesome!

On Mar 26, 2017 7:00 AM, "Stefan Trethan stefan_trethan@gmx.at [TekScopes]"
<TekScopes@yahoogroups.com> wrote:



We've all seen oscilloscope art before, but I haven't seen nothing like
this:
<https://youtu.be/TOjld0ZcNzs?t=533>

Thanks to Jong for digging that one up.

Below are the youtube channels of the artists responsible for this:
<https://www.youtube.com/channel/UCECl4aNz5hvuRzW5fgCOHKQ>
<https://www.youtube.com/user/hansiraber/videos>

ST


[Non-text portions of this message have been removed]


Re: OT: Where to get a good isolating transformer + HV isolation materials?

 

Hi David,

On Sun, Mar 26, 2017 at 3:37 PM, David davidwhess@gmail.com
[TekScopes] <TekScopes@yahoogroups.com> wrote:
On Fri, 24 Mar 2017 04:39:49 +0000, you wrote:

Ah great, I didn't know that Bel transformer could be used like this!

Can multiple isolating transformers be somehow used in series to obtain one
with a higher breakdown voltage?
Yes, but ...

How would one fix the voltage on the
intermediate windings?
That is the problem. Breakdown is also possible or even likely
between the winding or leads and the steel transformer core so the
core needs to be floated somehow as well.
Wouldn't a nylon spacer be plenty enough? Just some nylon struts, 1
inch to several inches in length, covered in corona dope?

If leakage is not a problem, then a resistor-capacitor voltage divider
can be made between the windings and cores so any common mode voltage
is distributed evenly between the primary and secondary.

Welp... leakage IS a problem... because you need the leakage to be
below a current that will kill you, and that's not a lot!!! It's the
voltage that gets you, but it's the current that kills you! So, say, a
spark gap is out of the question. But maybe a very low current, high
voltage rated incandescent could work? I wonder, at 10 kV, what sort
of current this would entail...

Also I wonder if this sort of thing would be safe... say you made a
circuit that allows current only run across the first OR the second
transformer but not both... would that entail safety? I think it
wouldn't... but I'm not sure.


Re: 2465 Vertical Gain

 

Gain control is through the vertical preamplifiers so it has to be
done electronically.

Maybe just the channel 2 vertical gain adjustment procedure can be
done?

On 26 Mar 2017 12:28:36 +0000, you wrote:

The CH 2 vertical gain on my 2465b is a few percent off, relative to the CH 1 gain, which is right on. Is there an adjustment pot for this, or do I have to go through the whole calibration procedure to fix it? The scope passes all the power up self tests and works beautifully otherwise. Thanks.

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