开云体育

Note that there are BNC adaptors on an extruded oval alloy shield which shrouds right down to the faceplate plane (at least hP sold these - probably others.) Wish I had a few more of these. With the shield physically connected to the black/common binding post, you have ..almost.. a fully shielded 'can'. Worked fine for the few-???V noise floors of the various sensitive good AC meters du jour.

(My lovely Racal-Dana 9300, good down to Boltzmann noise and to a phenomenal MHz top-end RMS, ~20 MHz at 6:1 crest IIRC? - natch was already BNC equipped.) Very handy with it's output amp sent to an accurate DC DVM, when you care about <0.1% relative levels.

Ergo "binding posts" need not be a huge handicap - anywhere near audio freq.

Ashton


J Forster wrote:

are those ever availible?
looks like alot better unit then a comparable hp 9825a
and the tek basic is fantastic for its day

For audio band distortions you just need what is called Wave Analyzer (in
other
words spectrum analyzer) in 5Hz -50kHz. I own one with some same spare - HP
analyzer for audio band.
Any scope is not capable to "see" small distortions....

Greg


At 04:14 PM 2/7/07 -0500, Kuba Ober wrote:

I was talking about "aligning" audio circuits, e.g. adjusting operating
points of various stages, checking response, etc. Not about any sort of
RF work.

If I wanted to see a nonlinearity of a stage in an audio power amp, for
example, it'd be nice to believe that the scope's vertical system is
linear enough, etc. Same goes for step response: hard to do with a scope
that may well distort even a perfect square wave.

Anyone who is at all capable of making those kind of measurements
would surely measure the input square wave first. If it looks like
a square wave, then the scope is good enough for the task.

The input will look like a square wave even with a badly nonlinear vertical
channel. The output "square" wave will then typically be much slower than

the

input one you fed to your system. With nonlinear vertical, the slower
transitions on the output square wave will look distorted, and you may

end up

chasing ghosts, especially if the audio amp alignment procedure mentions
e.g. "adjust Rxxx for output transitions to be smooth".

I just don't believe in using unchecked instruments, and a reasonable way

to

check a 7603 with plugins is to use the classic calibration trio in a

TM503,

plus a mainframe standardizer.

How on earth can anyone recommend using an unchecked, unknown scope to a

newb

is beyond me. Newbs tend to misunderstand limitations of instruments they
use, so they are very likely to just blindly trust the trace, even if

someone

experienced would check things twice first. You know, things like using too
much or too little of vertical deflection, not centering the signal and
hunting differing rising/falling edge aberrations, and so on. It's just

very

easy to hit those on an uncalibrated scope methinks.

Cheers, Kuba

Emacs!

because of modern technology
you aren't paying very much for all those modes
the software programming is amortized over a tremendous number
of units

True, but many (most) users REALLY don't want to have to read a 50+ page
manual to make a piece of toast or a cup of coffee. My reply was more
directed at "Why make it simple when complicated also works well"

How many of the VCRs you've seen over the last few years just sit and
blink 88:88:88 at you? Too many, IMO. I no longer bother to set mine
after a power fail.

-John

Everything from a wire wrapped 1802, low serial # Altair, early IMSI etc.

Most will still power up.

Hugh





arthurok_2000 wrote:

im quite familiar with the lsi11 and q bus
never was a great fan of the data general nova machines.

is anyone in this group other then dave wise
into old computers??

Yes, but not actively. Most of the Data General Nova line, but not
eclipses. Also some LSI 11s in the Tek DPO. Also Multibus and some VME.

-John

Interested, yes. Knowledgable, no.

Dave Casey

Chuck Harris <cfharris@...> wrote:

arthurok_2000 wrote:

is anyone in this group other then dave wise
into old computers??

I have an old PDP8/E with a TU56 dectape drive. In the
spirit of tektronix, I am looking for a 4010 to use with
it.

I *had* an LI-1000E clone of an IBM 1130, complete with 29M
12 platter top loading disk packs. It was card input (had the 029
keypunch, too) and had a 600lpm band printer. 'twas operational
in my living room. My oldies these days are considerably smaller
and newer. PDP8's & 11's are wonderful pieces of history. In fact
pretty much anything DEC made is nifty.
-ls-

arthurok_2000 wrote:

is anyone in this group other then dave wise
into old computers??

I have an old PDP8/E with a TU56 dectape drive. In the
spirit of tektronix, I am looking for a 4010 to use with
it.

-Chuck Harris

is anyone in this group other then dave wise
into old computers??

Kuba,

It is simple, very few newbies can afford to buy top dollar
calibrated equipment.

I have had the luxury of living near a surplus dealer that literally
has gone through tens of thousands of tektronix, HP and other scopes.
Of the Tek scopes, virtually all work, or are only slightly broken.
Typically the failures are mechanical (someone broke all the switches
on purpose), or the odd failed tantalum.

Every 7000 series scope that I have pulled out of his pile has worked
near perfectly after I have fixed the bad tantalums. Most were in perfect
calibration. As a caveat, I never pulled out any that had been smashed,
or were incomplete. There were so many, why bother with the trash?

So, I can without reservation recommend to a newbie that 7603 he finds
on Ebay that shows a clear waveform on the screen. Particularly if it
comes from a seller that has a reputation for selling checked out stuff.

Use an unchecked scope? Nope, you will have to look at some basic
signals. The calibrator will easily tell you if the amplifier is behaving
linearly. How? Simple, step through the calibrator output values, and
watch where the square wave's tops and bottoms hit on the graticule lines.
Set a 1cm square wave, and use the vertical controls to move it from the
bottom of the screen to the top, noting the size of the square wave.
Trying different V/cm values on the same voltage square wave, and note
the size changes. It's not complicated, and it is not at all hard.

If you do these simple things, your scope will be good enough for audio
work, and most other work.

-Chuck Harris

Kuba Ober wrote:

because of modern technology
you arent paying very much for all those modes
the software programming is amortized over a tremendous number of units

The title says it all. How are the TR502 and TR503 tracking
generators different?

They have different IF frequencies.

The TR502 matches the 7L series analyzers, the TR503 matches the 49x
series.

The title says it all. How are the TR502 and TR503 tracking
generators different?

Interesting note, I was using the BNC connections. I
also noted that I had some ground noise, and at really
low output levels, sometimes the desired signal would
be swamped by line current. But yes, I believe I
sorta know what you're talking bout.

I cleared some of it up by grounding the op-amp to the
frame with the signal gen in it.

An interesting note, I've had this problem with tubed
rf alignment equipment. I solved it by swapping the
ground and signal test points!

I later read from a Tek measurement something or
another, that it was just a kludge fix as floating the
scope : (

Thanks. I hope to actually stop playing and doing
more directed studying.

Thanks.



____________________________________________________________________________________
Don't pick lemons.
See all the new 2007 cars at Yahoo! Autos.

Couple of bullets for yall.

As I'm no RF engineer or even purport to know much about what goes on
inside a tuner, I rely upon service manuals! Wow, I bet most of yall
are saying jeez.

Anyway, equipment that is desirable, meaning non-disposable, have very
good service manuals. Yes, I'm a Golden Era of Audio, Crown & Yamaha
Maven. Their equipment is on a par or even better than the best of
Tek, especially their TOTL from either. Both have developed for the
industry and electronics community several advancements that go beyond
audio.

Anyways again; for Tuners:

I've had to work on analog, digital, and hybrid tuners. Working on
the analog stuff with some of the less performing gear is okay;
however, touch a modern digital tuner or Golden Age hybrid, you're in
for a nightmare.

Two of my tuners have analog tuning sections but motorized digital
presets! A wonder to see work, and work every time. Get any of the
alignment off and they go beserk! I use a Sencore SG80 and borrowed
distortion meter. The SG80 is wildly accurate, accurate to the
significance of my just calibrated by SIMCO DC503A Opt. 01!

Most stuff has power supply probs 'cause of bad caps and occasionally
diodes. Most of the time, the stuffs gonna work and be spot on or not
going to work. Occassionally, ya wonder why some stuffs just
performing as you've expected. Well, break out the great gear and get
to work!

I found that a bunch of stuff was off. Did I know or care what was
going on behind the scenes? Yes and know. I'd like to know later,
but wanted my distance stations to come on in! I wanted my amplifier
to stop getting a bit warmer than hot on one side--thermally both
sides were wildly different. Good thing, no oscillations!

GREAT manuals! Just followed the directions along with the equipment
recommendations just like the Tek manuals. Turned out the amplifier
(had two that I sold) was tampered with badly. All I had to do was
get the DC Balance and other stuff back in adjustment. The screws had
been removed except a few for the cover.

Say it like this; those amplifiers, Yamaha M-2 examples cost $1200 new
in 1979--1982! That's $5000 in today's money. Funny thing is, if ya
want an amplifier with those current reserves, continuous power
output, and protection, ya still gotta spend that amount!

This great gear for testing isn't cheap; however, the best gear
demands the best equipment. Cheap stuff (non-digital) won't push the
envelop. The Crown and Yamaha stuff does push the envelop and is well
worth every dime spent on proper equipment. If ya don't, especially
in the tuning world, ya just will be disappointed! Man, some of those
digital tuners have reeeeaaaaaaaallllyyyy low distortion figures!
That's why I had to borrow a distortion meter!

Now my dial calibration is spot on the one that was working okay,
while the other is spot on after looking great but performing
crappily. Go figure.

Later.

From: "jones_chap" <jones_chap@...>

[snip]

Interesting note about "anything with banana plugs" is that when
playing around with the AM501 plugins was a sensitivity of the output
based upon the proximity of my hand near the jacks. Wild and crazy
things would happen as I got anywhere near 'em, sorta. One was much
more sensitive than the other.

The noise, etc. is capacitively coupled to your circuitry. Reduce the
values of the components in the FB loop and it will go down or use a
grounded aluminum foil shield.
-John

customer dosent want to pay for complicated

Tell the Japanese TV, VCR, and cell phone designers that. My TV has more
programming modes than a 757.

8=))

-John

customer dosent want to pay for complicated