Enjoy.



-Kurt

From: glydeck@...
Subject: Re: [TekScopes] Re: Testing Vacuum Tubes with a Tektronix Model 576 Semiconductor Curve Tracer...
To: TekScopes@...
Date: Sunday, May 20, 2012, 4:29 PM

?

Jim,

Let me know if this works....

http://dl.dropbox.com/u/27593700/Testing_Vacuum_Tubes_with_a_Tek576.pdf

glydeck@...

-----Original Message-----
From: Jim Elliott
To: TekScopes
Sent: Sat, May 19, 2012 3:54 pm
Subject: Re: [TekScopes] Re: Testing Vacuum Tubes with a Tektronix Model 576 Semiconductor Curve Tracer...

?

I'm still unable to open.? My PC keeps telling me it is an unknown file type. ? Can you direct me to a program that will open the link? ? Thanks again, ? Jim --- On Sat, 5/19/12, <> wrote: From: <> Subject: Re: [TekScopes] Re: Testing Vacuum Tubes with a Tektronix Model 576 Semiconductor Curve Tracer... To: Date: Saturday, May 19, 2012, 6:31 PM ? The link was broken with a carriage return. ?Try this; -----Original Message----- From: jimafm <> To: TekScopes <> Sent: Sat, May 19, 2012 12:40 pm Subject: [TekScopes] Re: Testing Vacuum Tubes with a Tektronix Model 576 Semiconductor Curve Tracer... ? --- In , "c1ferrari" wrote: > > > > Happy New Year, all, > > Just wanted to report this article is unavailable on the web. > When I re-discover, LOL, the info pertaining to power supplies -- I'll post. > > Best regards, > Sam > > --- In , "c1ferrari" wrote: > > > > > > > > Hey Craig, > > > > Thanks for the reply! I'll see if I can get a link to the article with pics. I think Daniel had some suggestions for the necessary power supplies. > > > > Next for your stable...Tek 570 or 370, Craig? ;-) > > > > Season's Greetings, > > > > Sam > > > > --- In , "Craig Sawyers" wrote: > > > > > > Interesting article, Sam. > > > > > > > > > > > > I have (surprise, surprise) got a 577 as well as a 575mod122C (and a regular > > > 575 too). > > > > > > > > > > > > The key benefit of the 577 as compared with the much older 575 is that it > > > was designed after the FET became common - hence the step amplifier on the > > > 577 goes up to 2V per step as compared with 0.2V per step for the 575. It > > > also (as the article points out) has a much wider range of voltage and > > > higher current capability than the 575 - or the 570 for that matter. > > > > > > > > > > > > However, to be fully featured, it still needs a step amplifier to get to the > > > 10V/step needed for some of the more esoteric (audio) valves like the 300B, > > > and the characteristic curves for things like the KT88 call for 5V steps. > > > And a screen grid supply is also needed whatever tracer is used. And > > > although the formal definition gm is a limit (dIa/dVg at constant Va), and > > > that most tube testers measure with a 1V grid voltage step, you can get a > > > surprisingly accurate result by measuring between grid voltage steps and > > > doing the calculation on that basis. Or use the measurement method in the > > > paper Sam attached, which should be as accurate as the calibration of the > > > tracer. > > > > > > > > > > > > But (given screen grid and heater supplies) it is easier to do most small > > > signal and some power tubes with a 577 as compared with a 575mod122C for > > > sure. > > > > > > > > > > > > Craig > > > > > > > > > > > > PS it would be good to get a link to the article including the diagrams > > > > > > > > > > > > > > > > > > > > > > > > From: [mailto:] On Behalf > > > Of Sam Lucero > > > Sent: 23 December 2011 02:33 > > > To: > > > Subject: [TekScopes] Testing Vacuum Tubes with a Tektronix Model 576 > > > Semiconductor Curve Tracer... [1 Attachment] > > > > > > > > > > > > [Attachment(s) from Sam Lucero included below] > > > > > > > > > > > > > > > manuscript courtesy of its author, Daniel Schoo, is available, here, in pdf > > > format. Please note photos have been omitted due to bandwidth requirement. > > > > > > Daniel furnishes the article on the condition it be distributed and > > > reproduced with it's original content unchanged with no editing. > > > An accompanying article on the Tek 577 appears with it. > > > > > > Enjoy and Happy Holidays! > > > > > > Sam > > > > > > > > > > > > > > > > > > Attachment(s) from Sam Lucero > > > > > > 1 of 1 File(s) > > > > > > <> > > > > > > > > > < > > > es%20with%20a%20Tek%20Model%20576%20Semiconductor%20> Testing Vacuum Tubes > > > with a Tek Model 576 Semiconductor Curve Tracer.pdf > > > > > > The links don't work. Am I missing something? Anyone have input on Daniel Schoo's article on using Tek 576 to test tubes?

You have a function generator that goes to 50MHz and 100Mhz?

Your pictures are not labeled and it is not clear what your
oscilloscope's vertical deflection and sweep speed are set to so I am
not sure what I am looking at.

On Sun, 20 May 2012 03:21:34 -0000, "rebelliouszombie"
<santosismael@...> wrote:

I posted more pictures in my album (rebelliouszombie_album). I connected the oscilloscope to the function generator using BNC adapters. The function generator is generating a sine wave at 100kHz, 50MHz, and 100MHz. You can see that the traces are very noisy.

I'll check the bandwidth limiter and the coupling and report back. Thanks.

On 5/19/2012 12:08 PM, Herbert wrote:

Hello Steve,

please look in



which is in compliance to

Electrical and electronics diagrams, IEEE Std 315-1975, Section 3.9: Circuit return.

which is compliant to IEC 60617 !

I think,, and hope I should know, I am engineer and was teacher
for telecommunication sinc 1973 ?!

Keep smiling..... I do the same

Herbert

So, theoretically, they should all be isolated, correct?

Mark

?

I'm still unable to open.? My PC keeps telling me it is an unknown file type. ? Can you direct me to a program that will open the link? ? Thanks again, ? Jim --- On Sat, 5/19/12, glydeck@... <glydeck@...> wrote: From: glydeck@... <glydeck@...> Subject: Re: [TekScopes] Re: Testing Vacuum Tubes with a Tektronix Model 576 Semiconductor Curve Tracer... To: TekScopes@... Date: Saturday, May 19, 2012, 6:31 PM ? The link was broken with a carriage return. ?Try this; glydeck@... -----Original Message----- From: jimafm <jimafm@...> To: TekScopes <TekScopes@...> Sent: Sat, May 19, 2012 12:40 pm Subject: [TekScopes] Re: Testing Vacuum Tubes with a Tektronix Model 576 Semiconductor Curve Tracer... ? --- In , "c1ferrari" > > > > Happy New Year, all, > > Just wanted to report this article is unavailable on the web. > When I re-discover, LOL, the info pertaining to power supplies -- I'll post. > > Best regards, > Sam > > --- In , "c1ferrari" wrote: > > > > > > > > Hey Craig, > > > > Thanks for the reply! I'll see if I can get a link to the article with pics. I think Daniel had some suggestions for the necessary power supplies. > > > > Next for your stable...Tek 570 or 370, Craig? ;-) > > > > Season's Greetings, > > > > Sam > > > > --- In , "Craig Sawyers" wrote: > > > > > > Interesting article, Sam. > > > > > > > > > > > > I have (surprise, surprise) got a 577 as well as a 575mod122C (and a regular > > > 575 too). > > > > > > > > > > > > The key benefit of the 577 as compared with the much older 575 is that it > > > was designed after the FET became common - hence the step amplifier on the > > > 577 goes up to 2V per step as compared with 0.2V per step for the 575. It > > > also (as the article points out) has a much wider range of voltage and > > > higher current capability than the 575 - or the 570 for that matter. > > > > > > > > > > > > However, to be fully featured, it still needs a step amplifier to get to the > > > 10V/step needed for some of the more esoteric (audio) valves like the 300B, > > > and the characteristic curves for things like the KT88 call for 5V steps. > > > And a screen grid supply is also needed whatever tracer is used. And > > > although the formal definition gm is a limit (dIa/dVg at constant Va), and > > > that most tube testers measure with a 1V grid voltage step, you can get a > > > surprisingly accurate result by measuring between grid voltage steps and > > > doing the calculation on that basis. Or use the measurement method in the > > > paper Sam attached, which should be as accurate as the calibration of the > > > tracer. > > > > > > > > > > > > But (given screen grid and heater supplies) it is easier to do most small > > > signal and some power tubes with a 577 as compared with a 575mod122C for > > > sure. > > > > > > > > > > > > Craig > > > > > > > > > > > > PS it would be good to get a link to the article including the diagrams > > > > > > > > > > > > > > > > > > > > > > > > From: [mailto:] On Behalf > > > Of Sam Lucero > > > Sent: 23 December 2011 02:33 > > > To: > > > Subject: [TekScopes] Testing Vacuum Tubes with a Tektronix Model 576 > > > Semiconductor Curve Tracer... [1 Attachment] > > > > > > > > > > > > [Attachment(s) from Sam Lucero included below] > > > > > > > > > > > > > > > manuscript courtesy of its author, Daniel Schoo, is available, here, in pdf > > > format. Please note photos have been omitted due to bandwidth requirement. > > > > > > Daniel furnishes the article on the condition it be distributed and > > > reproduced with it's original content unchanged with no editing. > > > An accompanying article on the Tek 577 appears with it. > > > > > > Enjoy and Happy Holidays! > > > > > > Sam > > > > > > > > > > > > > > > > > > Attachment(s) from Sam Lucero > > > > > > 1 of 1 File(s) > > > > > > <> > > > > > > > > > < > > > es%20with%20a%20Tek%20Model%20576%20Semiconductor%20> Testing Vacuum Tubes > > > with a Tek Model 576 Semiconductor Curve Tracer.pdf > > > > > > The links don't work. Am I missing something? Anyone have input on Daniel Schoo's article on using Tek 576 to test tubes?

?

Attached is a couple of pictures of some 7587 Nuvistor testing I did
w/ a stock 575 curve tracer, if you want a feel for what you can "see"
with one.

One picture is a tired old 7587, the other one is a NOS one. Curve
settings were the same between them. (But I've forgotten what they
were now. :-> ) Hopefully the list won't strip them off. The
pictures are a little fuzzy, but they'll do.

There's a Measurements Concepts PDF book out there. "Semiconductor
Device Measurements" by John Mulvey that has all sorts of measurements
you can make using a curve tracer. Its pretty generic, and not
specific to any certain tracer. Unsurprisingly its semiconductor
specific, and does not have any specific vacuum tube section. I've
forgotten where I picked my copy of the PDF up, but thanks to whomever
had it posted.

David

On Sun, May 20, 2012 at 7:07 AM, Mark Wendt (Contractor)
<mark.wendt@...> wrote:
> Anybody know of a good video tutorial, or a good read with lotsa
> pictures of how a curve tracer is actually used, what the display is
> actually showing me, examples of both good and bad components under
> test, and nifty things to do with a CT that you normally wouldn't think of?
>
> All I really have at the moment, along the the 7CT1, is the manual, and
> it has a few diagrams of typical traces, but really doesn't go into much
> depth on explanations. ?I'm presuming when Tek wrote the manual that Tek
> presumed a modicum of knowledge of the operation of a curve tracer, but
> for someone who hasn't used one in the past, the manual doesn't quite go
> far enough, at least for me.
>
> Thanks,
> Mark
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>

----- Original Message -----

From: Fabio Eboli

To: TekScopes@...

Sent: Sunday, May 20, 2012 11:23 AM

Subject: [TekScopes] First avalanche pulser and 7A26

?

Hello, today I had a little fun trying
to build my first transistor avalanche pulser.
To my great surprice after half an hour
I had the first pulses out of the circuit.
The schematic is the classic AN47page 93.
The components used were what I had at hand
at the moment:
1u On voltage input followed by a
1Mohm to transistor collector and
a trimmer capacitor of something around 2-10pf
(not sure about this, my capmeter doesnt fare
well at these resolutions) to ground; on the emitter
i used a 56ohm; 75kohm on the transistor
base, simply because I was misled by color codes
and was thinking it was a 15kohm :)

The first transistor didnt avalanche at all, i dont
remember the code, the second was a bc238 that
avalanched at about 240V but with slow pulses.
The third transistor started generating cute
pulses at 140-150V, it's an stc945.

the pulses are very steep but it seem that
are a little high voltage, the rep. rate
is around 28kHz.

I started using the sds7102 to check for
initial setup, I used its' probes that are
low cost 100MHz probes that come with the
instrument, are marked P5100.
I used the same probes for 3 scopes compensating
them for each instrument.

Here is one of the pics of the pulser:


This is the pulse as seen from the
philips PM3217, this is a 50MHz scope with a 7nS
declared risetime, the first is the pulse adjusted
to show the risetime, approx 4nS



here the pulse as seen at 10nS per div and 1V (x10)
per div



here the pulse seen from the sds7102, a DSO 1GSps 100MHz
(others reported that the input BW is much is wider than this)

risetime about less than 2nS, rep. rate 28kHz:


And here we come in topic :)
This is the good channel of the 7A26 in the R7103

adjusted for risetime: 1,4nS, TB is a 7B92A:

amplitude something around 30-40V on the probe tip

What do you think?
Any improvement suggestion about the circuit is welcome!
I dont know if there is a meaning in these, I see very
steep pulses but I'm using cheap probes.
What could I do to not use these ceap probes, apart
buying a 7A29 and a pair of good Tek probes (will not
happen soon :) ?

Can I conclude that the Philips has a 4nS risetime?

Now I'll build a power supply to have the thing powered
from some battery.

Fabio.

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