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I'm in Camberley, Surrey

By the way, my storage 577 has similar "quirks" to yours. I tried adjusting it according to the
manual
and I found the directions very confusing. I finally gave up. Now I am happy that it works well
enough
that I can use it when I need to and if I get a small cloud when I first turn it on pressing the
erase
button always makes it go away so it is not a problem.

Oddly enough storage was/is perfect on my 577. That isn't the problem. A couple of years ago I had a
tant go short. To locate which board was the problem, I unplugged the power supply. Finding the
problem was then obvious and said capacitor was replaced.

Then I plugged one of the darned cluster of harmonica connectors one pin out, and the magic smoke came
out. I was so angry, disappointed with myself, and discouraged I parked it for a year. Then I set
about replacing everything that was clearly ex-silicon and a new clutch of ex-tants. Logic chips had
had some horrid voltage and most were dead. Op-amps were dead. There are two dual JFETS in there, that
were clearly dead - and much to my delight they are still currently available parts.

This saga was behind my word of caution to Wolfgang to check the connectors were plugged in correctly.

Now everything works apart from a remaining gremlin in the step generator or amplifier, so at least
I've put the magic smoke back in at last. It is again parked waiting for another burst of fixit
enthusiasm.

Craig

Hi Dave
Approximately where in the UK are you, I may be able to help you.
George ?G6HIG

Hi Wolfgang,

Excellent!
By the way, my storage 577 has similar "quirks" to yours. I tried adjusting it according to the manual and I found the directions very confusing. I finally gave up. Now I am happy that it works well enough that I can use it when I need to and if I get a small cloud when I first turn it on pressing the erase button always makes it go away so it is not a problem.

There are several valuable things you can do with the storage 577 that the 576 cannot do so that is one reason I prefer the 577. One odd advantage I discovered to the storage is that since the 577 graticule is not illuminated it can sometimes be hard to capture it in a photograph, but if you turn the storage gun up a bit it creates a uniform green fog effect that back lights the graticule just enough that you can see it and your transistor curves together making it easy to get both in the photo.

Dennis

Thank you Dennis.
I did accept that this fine instrument is working as specified. My last comment was regarding the storage option which I am not really worried about.

I apologize if I gave you the impression that I am not trusting the very helpful advice I received in the last couple of days. I truly appreciate all the help I received.

Thank you again,
Wolfgang

Hi Wolfgang,

Please forgive the capital letters. I am not shouting but I do hope to get your attention to what the other TekScopes experts (Craig Sawyer, Chuck Harris, Tom Jobe) are telling you:
* THERE IS NOTHING WRONG WITH YOUR CURVE TRACER!!!!
* YOUR FINE PHOTOGRAPHS SHOW A PERFECTLY NORMAL SET OF 2N3055 CURVES ON A 577.
No matter how much you think your photos show your curve tracer is not working it is working perfectly.

Just in case that was not clear let me say it a little differently:
* YOUR 577 IS WORKING EXACTLY LIKE ALL OF THE 575s, 576s, AND 577s I HAVE EVER USED (I OWN 5 AND I HAVE USED MORE THAN 20).

There are several things that are causing this misunderstanding on your part:
* Several of the curve tracer controls interact with each other and/or with the transistor's actual parameters to create misleading (or annoying at best) visual artifacts that you are pointing out as performance defects of the curve tracer such the loops on the left side of each curve. Those are characteristics of the transistor itself. Others have pointed out how to prove this by substituting a small value capacitor for the transistor to see that it creates loops too.
* Your expectation of what ideal transistor curves look like conflicts with 1) how real transistors (with stray capacitances and other ugly details) actually perform; and 2) how real world instruments such as a 577 operate due to limitations of real world circuit designs, or constraints like costs, weight, size, heat, etc.
* Your incorrect expectations of what transistor curves SHOULD look like on a curve tracer are confusing you further and further.
* You don't have enough experience with Tek Curve Tracers to realize that yours is operating perfectly.
* You do not have enough hands-on experience with curve tracers to realize the subtleties of how they operate. For example I have 50+ years of experience with the 575/576/577 and I still haven’t used every capability of these sophisticated instruments.
* The designers of the 576/577 knew it would have to test devices that weren't invented yet. As a result these curve tracers have many more controls and capabilities that they would seem to need. Until you need these capabilities those controls only create more confusion if you set them wrong. This is part of your problem.
* There is no blanking on the 575/576/577 so you see the unusual traces between steps at the right side of each step in your photos. This is because you were using the FAST Step Rate. I could explain why this is so but it would be better if you learned why yourself (from the Theory of Operation" section in the Service Manual) so you would realize it is not a sign that there is something wrong.

Regardless of what "wrong" curves you get on your 577, if you provide a photo, we can explain why the curves look that way. It will either be due to:
1) The settings of the curve tracer (such as using the FAST Step Rate),
2) The way the curve tracer circuitry works (it doesn't use blanking),
3) A real world transistor is not the same as an ideal transistor (Miller Effect, leakage, etc).

If I succeeded in reassuring you that your curve tracer is working properly, CONGRATULATIONS!
On the other hand, if Craig, Chuck, Tom, and I haven't convinced you, then I suggest you sell the curve tracer. You will never be happy with it and you are going to waste a lot of time and money chasing a chimera.

My only request is that you think about how much time we have spent so far explaining to you that there is nothing wrong before you ask us for further reassurance. It won't be a good use of our time.

I hope you are able to stop worrying and begin to enjoy the remarkable instrument you have. You can download a copy of the Tek book "Semiconductor Device Measurements" (link below) to learn how to use your curve tracer to make all sorts of device measurements. If you look carefully you will see the steps have loops in some of the photographs in this book.


Dennis Tillman W7PF

I sold 1 and parted 2 R7603's out recently, but the pcbs are mostly gone now.

They are still attractive to people/engineers. 7xxx plugins like 7A13 7A22 7A26 7A11 7A24 7B92A 7B10 7B15 7A29
are really a big draw.

7A26 and 7B53A are cheapish plugins.

I have a spare 7603 and a
whole barrel full of plug-ins,
but you are a tad far from
Arizona.

Regards, Dick, W1KSZ

The 2335 / 2336 / 2337 are very portable and rugged but they have a fairly
small screen. No readout, not nearly as versatile as the 7000 series, but a
lot more portable than a 7603.

Dave Casey

On Mon, Nov 26, 2018 at 7:50 PM george edmonds via Groups.Io <G6HIG=
[email protected]> wrote:

Hi
You call a 7603 smallish?
George G6HIG

On Tuesday, November 27, 2018 1:40 AM, David Slipper <
softfoot@...> wrote:



I need a smallish analogue two channel scope that can get up to 50 to
100 MHz

I don't particularly want storage.

How is the 7603- for example?

Dave

I'm in the UK - and yes the 7603 is at the very limit of "smallish" ;-)

Hi
You call a 7603 smallish?
George G6HIG

When you consider he wide
range of plug-ins the 7603
takes, plus the big screen,
it's worth while looking at.

Where are you located ?

73, Dick, W1KSZ

I need a smallish analogue two channel scope that can get up to 50 to
100 MHz

I don't particularly want storage.

How is the 7603- for example?

Dave

WAG - check the beam finder switch. Maybe spray some contact cleaner in it and work it several 10's of times.

Regards

I have a Tektronix Model 2215 to give away. It’s a 60MHz dual trace ‘scope, but it has a PSU fault, so it doesn’t power-up correctly. Probably an easy fix, but I just haven’t had time to look at it and in the meantime I bought a Rigol, which suits my purposes better.

Sorry it’s collection only, first come first served. I’m in the Brighton area of the UK.

Email direct to g4gnx AT g4gnx.com

Regards,

Alan.

I know my board is too new for caps. Where should I start looking

verification reply

Randall Pallesen

Bison
Information
Technology Services. Inc.

randall@...
voice (913) 901-7626 "updated 08-2018"

My recently acquired 465B Tektronix Oscilloscope has a problem I can't seem to track down. Both Traces are about half the length of the Screen Display and the Position Knob will only Bring the Traces Sweep Start to Center of the Display when turned full CCW. All Power Supply Voltages and Ripple are in Spec. I've pulled and Tested all Transistors on the Interface Circuit Board...all Tested good. All Published Voltages on the Horizontal Display Logic and A & B Sweep Generators Schematic are Spot On. Voltages on the Horizontal Amplifier Schematic however are all off somewhat from Published. Visually...everything looks normal except I can see one Resistor R4368 (3.74 K) in the Paraphase Amplifier has been replaced.

All sources are referenced to the +50 volts. Start there. Once you get 50 volts there everything else should fall into place.

Likely the Zener in the 50 volt, I THINK it's the only one they use.

Ok a long while back I pulled down both the torrents in question, but where
does this stuff actually live! Is there a website that hosts it?

Thanks
David