Date   
Re: 7L12 spectrum analyzer 'voltage memory'

cmjones01
 

On Tue, Feb 13, 2018 at 08:03 am, Chuck Harris wrote:
YIG oscillators exhibit classic hysterisis.
I didn't know that, very interesting. I guess the hysteresis would have no effect during normal operation, when the sweep is only going in one direction, but if the sweep of the YIG frequency stops and starts again (as it does when going between 0.2MHz/div and 0.1MHz/div) all sorts of strange things could happen.

Chris

Re: Curve tracer plug-in for 500 series.-

widgethunter
 

Sebastian;
I've been wanting the same for use with Dennis' board.
Plenty of 500 mainframes and plug-in frames, but also 'low on resources'.
Bernd Schroder

-----Original Message-----
From: Sebastian Garcia <sg-listas@...>
To: TekScopes <TekScopes@groups.io>
Sent: Mon, Feb 12, 2018 3:35 pm
Subject: Re: [TekScopes] Curve tracer plug-in for 500 series.-

Thank you very much for your comments, Dennis.

I'll read the CTs and CT plugins docs, to understand their ups and downs.

I'm with low resources for this right now, but having here some 500-series
scopes will try to leverage one for this.

Best regards,
Sebastian.




Dennis Tillman W7PF wrote:
Hi Sebastian,

The 5CT1N is quite uncommon. I was lucky to find one but it took years of
waiting for one to appear on Ebay. The 7CT1N appears far more often on
Ebay
for about the same price as the 5CT1N ($200 to $300). While they can both
test tubes with my adapter they have some serious limitations on the plate
voltage they can apply to the tube, but more importantly they are severely
limited in how much power they are capable of. As a result they can only
apply a few milliamps of plate current. This puts real limits on the kinds
of tests you can perform. If you are looking to confirm whether a tube is
working or not it will be capable of determining that for you but if you
intended to do any design work where knowing the tube's parameters and how
it will actually perform in a circuit you would need a 577 curve tracer
instead.

Of all of the curve tracers Tek makes the 577 has the best combination of
weight, size, capability, and availability and "price to performance
ratio"
to meet your needs. That is the one I suggest you consider looking for.

Good luck, Dennis Tillman W7PF

PS I was not aware of ANY curve tracer plugins for the 500 series scopes
until you mentioned the Systron-Donner plugin. Someday I hope to see one
in
use so I can see how it works.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
Sebastian Garcia
Sent: Sunday, February 11, 2018 6:53 PM
Subject: Re: [TekScopes] Curve tracer plug-in for 500 series.-

Hi Harvey, thank you for your message.

I need a curve tracer, mainly for tubes.
Tek curve tracers seem lovely, but here in this corner of the world these
are not easy to find. And trying to pass a large and heavy used equipment
through the Customs of my country is a random problem.

So, I'm evaluating developing a custom plugin for a 500-series scope,
that's
the reason of my request.

Another option would be to buy a 5115 locally (have one in sight), try to
get a reasonably priced 5CT1N from eBay, and use something like Dennis
Tillman's circuit.

Any comments are welcome.

Best regards,
Sebastian.

---
Harvey White wrote:
On Sun, 11 Feb 2018 21:36:49 -0300, you wrote:

I'm looking for technical information on this kind of plugin module,
either standard or custom built.
500 series. Never heard of one. The only plugin I know of is the
5CT1N (for a 5000 series scope) or the 7CT1N for the 7000 series
scope.


The only one I know about is the Systron Donner 9550 [1], but
unfortunately I haven't found any manuals.
Never heard of it myself. Tek did make some curve tracers, but they
seem to go for a lot of $$$$.

You could build yourself one, but then there's the question of analog
or digial, and then how sophisticated you want to be.

You normally need a voltage or current step generator, variable
polarity, and a sinewave sweep, variable polarity. That's pretty much
what's in the 7CT1N series.

Your choice from here.

Harvey

Any data about something like this will be greatly appreciated.

Regards,
Sebastian.

[1] http://w140.com/tekwiki/wiki/File:Systron-Donner-9550-1.jpg



--
Dennis Tillman W7PF
TekScopes Moderator



Re: Tek 2430A - please tell me it's a good scope... :]

 

The main weakness of 2430/2430A is the CCD hybrids.
They came in, IIRC, 6 versions, 165-2074-00 thru 165-2074-05 and most of them aren't interchangeable.
Those are the large ones on the center of the mainboard. If you have -04 or -05 you are good.
Any lower prefix could be less reliable and may eventually fail.
If you take the cover off to examine do not power up the scope without forced cooling i.e. an external fan.
/Håkan

Re: 7D15 plugin issue

Harvey White
 

On Tue, 13 Feb 2018 12:54:33 -0800, you wrote:

Hi all,
I need some help with a 7D15 plugin that I just acquired. When I put it in one of the two horizontal (right) slots of my 7904A scope, the scope won't turn on. It just makes that clicking sound. I shut the scope off immediately when I saw what it was doing. Without the 7D15 in there, the scope works fine.
Does this sound like a possible failed tantalum cap or something like that?
That would be an absolutely wonderful first guess. Power supply
overload.

I once had (and still do) one of those that did much the same thing.
Had most of the lights in the lab off and noticed that the little red
LED in the circuit board was glowing dimly.

wait.....

WHAT little red LED?

Turned out it was a red hot tantalum.

Harvey


Any suggestions or help would be greatly appreciated.
Thanks,
Steve


Re: Logic Analyzer Recommendations?

Harvey White
 

On Tue, 13 Feb 2018 11:45:54 -0800, you wrote:

Harvey

I Might be off a model number or two and I can't seem to find it right now,

but I thought there was a schematic of the termination needed on the end of
the 40 pin connector. So that one could build, for example, a pcb that that
the cable could plug into, have the termination parts and then connect to
the S100 Buss
Yes, there is such a thing. HP actually made a resistor network that
contained this, and I've never seen it.


Two R's and A little C for each line????
One RC parallel network. You figure in the cable impedance and then
in the logic analyzer itself is the remaining resistor.

So a clean connection.
Exactly. Now there's another alternative I'd recommend for a lot less
fuss. HP made an adaptor, 40 pin to 20 pin (has all the signals,
clock, etc). It contains the resistor networks. I'd recommend it. 16
channels + clock. Part number 01650-63203 termination adaptor. I
design the 20 pin connector into projects. I've tried the other
approach, I think a 90.9K resistor with 7 pf in parallel. I'd go with
the termination adaptor.

Clean connection, too.

Harvey


I ended up with a SCSI Interface pod that I think does the same sort of
thing.
Yep, may make (or find) one of those one day, just don't need it yet.

H.

John


-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Harvey
White
Sent: Tuesday, February 13, 2018 7:31 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Logic Analyzer Recommendations?

On Mon, 12 Feb 2018 22:49:44 -0800 (PST), you wrote:

On Mon, 12 Feb 2018, jafinch78 . wrote:

Thanks Rich.

I appreciate the feedback and discussion thread as I've thought about
investing in a LA, though haven't read into very detailed yet since I'm
not that deep into the digital world so far.

In regards to the cables; are those more than ribbon cables with the fine
grab tips, i.e. extra shielding, capacitors, etc.?
All resistors/capacitors/whatever are in the PODs. Cables are mere 1:1
[twisted pair] flat cables, nothing to write home about. They might have
some fancy connectors on the blade side but that's it.

All level shifting, high impedance or whatever networs etc are in the PODs.
There are tens of different PODs available in any imaginable signal
standard
and form factors.
There are, that I know of, two specific types of pods. One is a
passive signal input. The others are for the stimulus generators, the
16520/21 and the 16522. These are memory based pattern generators
that output a simulus to the device under test. Those specifically
have outputs like TTL, TTL open collector, 3 state, ECL, etc. They
are not needed for any of the input blades.

The general input pods fall into three types, depending on the
bandwidth required. 1) inexpensive, the 20 pin and 40 pin breakouts,
general use. 2) expensive, odd high speed connectors and form factors
needed for very high speed connections, lots of $$$. 3) specific
breakouts, for instance, there's a 488 bus breakout. There are likely
processor breakouts where you plug in your LA to a box, then have a
clip going to the processor. IIRC, these are mostly passive with
perhaps a bit of decoding for processor states. If that's all there
is, you could build one on an S100 breakout (recommended).

Harvey




---
******************************************************************
* KSI@home KOI8 Net < > The impossible we do immediately. *
* Las Vegas NV, USA < > Miracles require 24-hour notice. *
******************************************************************








7D15 plugin issue

Steve Kessisoglou
 

Hi all,
I need some help with a 7D15 plugin that I just acquired. When I put it in one of the two horizontal (right) slots of my 7904A scope, the scope won't turn on. It just makes that clicking sound. I shut the scope off immediately when I saw what it was doing. Without the 7D15 in there, the scope works fine.
Does this sound like a possible failed tantalum cap or something like that?
Any suggestions or help would be greatly appreciated.
Thanks,
Steve

Explanation 491 Performance Check step 9 ?

Albert Otten
 

Could someone please explain how Type 491 Spectrum Analyzer Performance Check step 9 "Check Sweep Timing" is supposed to work? Page 5-3 or pdf page 77 (of 250) in the manual. Sweep is set at 1 ms/div. Type 184 markers "10 ns and 1 ms" output to band A input. This setup is (finally) supposed to produce several "markers" on the screen while Dispersion is set to 0 (i.e. fixed IF frequency) and INT triggering is selected. I can only understand such when a 100 MHz signal from the 10 ns markers is only present during a 1 ms marker and the "bursts" of 100 MHz signal thus show op 1 ms or 1 div apart. But the (or my) Type 184 doesn't work that way. The selected markers are added in the output stage, not multiplied. There is only a very slight change in 100 MHz amplitude during a 1 ms marker.
In my manual someone wrote notes that a HP 608D was used with 1 ms markers for external pulse modulation.

Albert

Re: Logic Analyzer Recommendations?

ykochcal
 

Harvey

I Might be off a model number or two and I can't seem to find it right now,

but I thought there was a schematic of the termination needed on the end of
the 40 pin connector. So that one could build, for example, a pcb that that
the cable could plug into, have the termination parts and then connect to
the S100 Buss
Two R's and A little C for each line????

So a clean connection.

I ended up with a SCSI Interface pod that I think does the same sort of
thing.

John

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Harvey
White
Sent: Tuesday, February 13, 2018 7:31 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Logic Analyzer Recommendations?

On Mon, 12 Feb 2018 22:49:44 -0800 (PST), you wrote:

On Mon, 12 Feb 2018, jafinch78 . wrote:

Thanks Rich.

I appreciate the feedback and discussion thread as I've thought about
investing in a LA, though haven't read into very detailed yet since I'm
not that deep into the digital world so far.

In regards to the cables; are those more than ribbon cables with the fine
grab tips, i.e. extra shielding, capacitors, etc.?
All resistors/capacitors/whatever are in the PODs. Cables are mere 1:1
[twisted pair] flat cables, nothing to write home about. They might have
some fancy connectors on the blade side but that's it.

All level shifting, high impedance or whatever networs etc are in the PODs.
There are tens of different PODs available in any imaginable signal
standard
and form factors.
There are, that I know of, two specific types of pods. One is a
passive signal input. The others are for the stimulus generators, the
16520/21 and the 16522. These are memory based pattern generators
that output a simulus to the device under test. Those specifically
have outputs like TTL, TTL open collector, 3 state, ECL, etc. They
are not needed for any of the input blades.

The general input pods fall into three types, depending on the
bandwidth required. 1) inexpensive, the 20 pin and 40 pin breakouts,
general use. 2) expensive, odd high speed connectors and form factors
needed for very high speed connections, lots of $$$. 3) specific
breakouts, for instance, there's a 488 bus breakout. There are likely
processor breakouts where you plug in your LA to a box, then have a
clip going to the processor. IIRC, these are mostly passive with
perhaps a bit of decoding for processor states. If that's all there
is, you could build one on an S100 breakout (recommended).

Harvey




---
******************************************************************
* KSI@home KOI8 Net < > The impossible we do immediately. *
* Las Vegas NV, USA < > Miracles require 24-hour notice. *
******************************************************************


Re: Did Tek produce a "normal" d.c. to 50 GHz scope that one could easily poke around with ? { vs. the 11801 / 11802/ 11803, CSA 803 series }

cmjones01
 

On Tue, Feb 13, 2018 at 10:50 am, Leo Bodnar wrote:
You are probably thinking of DL-11? http://w140.com/tekwiki/wiki/DL-11
You're quite right, that's the one. Thank you for the correction.

Another delay line trick I have used is inserting it into the circuit under
test before the stage/driver you are working on but tapping the trigger off
before the DL. This way observed signal is delayed but the driver remains
undisturbed (assuming it can tolerate degraded risetime at the input.) This
will break most systems but is useful for characterising the
driver/interconnects performance.
A neat trick. Thank you for the hint - I'll remember that one!

Chris

Re: Tek 2430A - please tell me it's a good scope... :]

cmjones01
 

On Tue, Feb 13, 2018 at 10:01 am, Marcin Marzeta wrote:
My first post here. I'm in Poland and I design and build tube guitar amps.
Welcome. I'm also in Poland though I don't design and build guitar amps :-)

Yesterday I snapped and bought a 2430A. I think I really need built-in
measurements as they make life easier. The problem is I'm not sure if I made a
good choice... 2430A I bought looks fully working with all originall manuals
and even probes, very good condition. So I'm actually looking for a general
opinion on the model - is it a good one?
It was a pretty decent portable digital scope in the early 1990s. I have one too which I still use regularly. I like it because it drives like the 2465 analogue scopes I'm used to, and because the first ever digital scope I used as an apprentice was a 2430. I remember having to ask special permission to get it out of a locked cupboard and use it. Now I have my own I don't have to ask anyone!

Even cheap modern digital scopes will beat it on the kind of specs that get obsessed over in some fora (record length, number of waveforms per second, that sort of thing). However, those things don't matter very much in everyday use, especially if you're used to an analogue scope and use the digital one as a sort of enhanced version of it. The 2430A, being an expensive unit when new, is relatively free of the strange vices and software bugs that can plague some modern scopes. While it has different limitations, it also has some features which are harder to find these days such as the peak detection and roll mode.

While not necessarily the best tool for analogue work (there lots of things on an analogue waveform it won't necessarily see as well as an analogue scope, for example a megahertz burst of instability on an audio-frequency sine wave) it should serve you well when you do want the digital features and measurements.

Chris

Re: Tek 2430A - please tell me it's a good scope... :]

Vince Vielhaber
 

I have two of them. I like them both.

Vince.

On 02/13/2018 10:02 AM, Marcin Marzeta wrote:
Dear Group,

My first post here. I'm in Poland and I design and build tube guitar amps.
I currently own a reliable 7603 and have recently started fixing my old 465 with DM44.

Yesterday I snapped and bought a 2430A. I think I really need built-in measurements as they make life easier. The problem is I'm not sure if I made a good choice... 2430A I bought looks fully working with all originall manuals and even probes, very good condition. So I'm actually looking for a general opinion on the model - is it a good one?

Re: Did Tek produce a "normal" d.c. to 50 GHz scope that one could easily poke around with ? { vs. the 11801 / 11802/ 11803, CSA 803 series }

Leo Bodnar
 

Chris,
You are probably thinking of DL-11? http://w140.com/tekwiki/wiki/DL-11
Another delay line trick I have used is inserting it into the circuit under test before the stage/driver you are working on but tapping the trigger off before the DL. This way observed signal is delayed but the driver remains undisturbed (assuming it can tolerate degraded risetime at the input.) This will break most systems but is useful for characterising the driver/interconnects performance.
Leo

On Tue, Feb 13, 2018 at 07:00 am, cmjones01 wrote:

I've built the delay lines from a scrap 11802 into my CSA803A, and they have a trigger pickoff
output. Their risetime is about 70ps, bandwidth thus about 5GHz. I think Tek
made the same thing in its own box and called it the DL-1.

Re: Tek 2430A - please tell me it's a good scope... :]

Harvey White
 

On Tue, 13 Feb 2018 07:02:45 -0800, you wrote:

Dear Group,

My first post here. I'm in Poland and I design and build tube guitar amps.
I currently own a reliable 7603 and have recently started fixing my old 465 with DM44.

Yesterday I snapped and bought a 2430A. I think I really need built-in measurements as they make life easier. The problem is I'm not sure if I made a good choice... 2430A I bought looks fully working with all originall manuals and even probes, very good condition. So I'm actually looking for a general opinion on the model - is it a good one?
I have one and I like it. Nice portable scope. Bandwidth should be
fine for what you do.

Harvey

Re: Questions on impedance matching

Harvey White
 

On Tue, 13 Feb 2018 09:47:27 -0800, you wrote:

@harveyW

thank you for your thoughtful responses. I'm struck by the common use of "maximum power transfer" which is a semantic twist. It's true... you want maximum power transfer (that's the point at which impedances match.. .clearly important in RF applications). But across audio and RF, what I'm hearing is that it's about "optimal power transfer." From what I'm reading, optimal power transfer for audio at short distances is different from optimal power transfer for RF at long distances. IOW, you're not maximizing power transfer with audio because reflection is a non-issue (a principle I still struggle with as documented in one of my other responses). With audio, you might as well go for maximum voltage transfer instead because there's no reflection penalty.
Take an antenna driven by an RF power amplifier. Maximum power is
delivered to the antenna when the line impedance matches that of the
load and is completely resistive. It's the inductive or capacitive
nature of the load that causes the worst reflections (IIRC).

For small signals, the typical input impedance of what you're driving
is so high in comparison to the driving impedance, that you are
delivering very little power to the load (seriously, one volt across
one meg is 1 microwatt....).

There is always a reflection of some sort, but if it's small enough,
it can be ignored. (and often is).



You said that wth RF, line length is a multiple of signal wavelength. What's an example of that? What's an example of the wrong multiple that results in reflection? Based on what you said about the length of audio wavelengths, I'm assuming that the same wrong multiple when plugged into the math with the long wavelengths of audio will show that the distance for reflection to matter must be so huge that it's irrelevant (thus putting some math behind the general theme that reflection is pretty much irrelevant with audio).
Ok, take 2 meters Ham radio, roughly 144 to 148 Mhz, wavelength is
(surprisingly) 2 meters, so an unterminated line will reflect back a
portion of the energy with the line length almost anything. Now take
20 Khz, wavelength is what, 8000 meters? firstly, anything coming
back from a decent length of cable, say 30 meters or so, will be
almost completely in phase, so there's little if any phase distortion,
I *think* that the vectors will add enough that any reflected power
will be in phase, and not cause problems enough. The amount of power
reflected back is so miniscule that it has no real measurable effect.
(you could always construct a scenario where it would, but the low
source impedance tends to swamp the reflections).



Lastly, in your response, you hinted at something I've read about where mismatched impedance in RF applications overloads the source to the point of damage due to reflected power.
Particularly a problem with RF power amplifiers and transistors.

With audio amps (guitar in particular), I've read that an impedance issue will simply blow-up a transistor, or in the case of tube amps will stress the tube out (tubes are heartier and can recover.. but repeated stress will destroy them).
Failure mechanisms in transistors are generally linked to either too
hot, too much current, or too much voltage. In a guitar amplifier,
the speaker current is proportional to volume and inversely
proportional to the load impedance. So mismatching the speakers would
be more or less OK until you exceeded the current rating of the
transistors. Ditto if the transistors were inadequately heatsunk (new
word...). Overvoltage is less of a problem unless a part fails, I
think.

Tubes are generally ok for voltage here, but the current can be a
problem. The output transformer has limits, too. The transformer
(and tubes) are matched to allow the normal temperature rise under a
nominal full power (assuming a good design), ditto for the power
supply components.

Is that strictly in situations where the load impedance is too low? Originally, I thought the stress was associated with over-voltage.
Load impedance too low causes the driver to have to handle more
current. This can create problems just for the driver, let alone
anything else in the line that may or may not handle the current.

But as I read all these posts, I'm hearing that you essentially want the most voltage possible, up to the max capability of the source. Or, maybe that's the problem? That tubes and transistors have no physical limitation? So if you keep pushing the impedance, the transistors and tubes will attempt to deliver the voltage until they fail?
For a signal transfer (minimal power) you generally want to minimize
voltage loss. Everthing low impedance until you get to a high
impedance load. For power transfer, you want to match the load to the
source.

Tubes and transistors have a definite limitation. But in any circuit,
there are safe operating areas, exceed those, and something is
stressed. Depends on what is stressed and how it responds as to what
happens.

Harvey





Re: Questions on impedance matching

Göran Krusell
 

Hi Ted,

is the last part of your discussion correct? I am not all that convinced
since your are not taken
the limited amplifier bandwidth into account.

Göran



2018-02-13 18:37 GMT+01:00 Ted Rook <rooknrol@...>:

David, I believe the following to be accurate but I am no physicist :-)

The reflection arrives back at the source with a delay that is
proportional to twice the distance
between source and load, the reflection is travelling at approximately
half the speed of light.

For the sake of argument assume the signal is a 20kHz sinewave, the period
is 50usec, the
half-period is 25usec. Here is a question, given that the reflection
travels at half the speed of
light how long would the line have to be for the reflection to arrive back
at the source with a
delay of one half period, 25usec?

This question can be rephrased: The line is 5 feet long, the reflection
travels at half the speed
of light, the signal is 20kHz sinewave, the reflection arrives having
travelled 10ft with a small
delay, what fraction of one period (50usec) is this delay?

The amplifiers in question are negative feedback amplifiers. The physical
length of the
feedback path around which the feedback signal must travel from the
amplifier output in
order to reach the input network and do its work is a small distance,
inches. The feedback
signal travels this path at approximately half the speed of light. The
reflection signal arrives
back at the source after a delay analysed in the paragraph above. It is
attenuated and the
residual is summed at the output and combines with the feedback signal
that travels back to
the input network of the amplifier. Because the distance around the
negative feedback loop is
small the feedback signal arrives back at the input very quickly, and long
before the reflection
arrives from the load which is 5ft away. The situation might be summarized
this way: the
negative feedback loop is very fast compared to the reflections coming
back from the load.
Errors induced by reflections are cancelled out immediately by the
feedback loop.

Ted




On 13 Feb 2018 at 8:55, David Berlind wrote:

@tedR

Thanks so much for your various responses.The link to Dr. Leach's work is
FANTASTIC.
Probably enough bedtime reading for a year or more (at the pace I consume
such texts). I
may have to build that Fisher KX-200 for fun. The voltage-db and power-db
conversions were
very helpful. In your opinion, is there a typical target decibel
improvement? Regarding
reflections, I'm glad I have company in @jafinch78 on the confusion front
(I'm not alone!).
You said "In this condition reflected energy is attenuated by the source
impedance behaving
as a low impedance sink." I thought I saw or read somewhere that the
refections interfere
with the output signal in transit. For example if the reflection is 180
degrees out of phase, it
practically cancels the signal. Do I have that incorrect? I'm trying to
understand why distance
or frequency renders this effect moot in audio. Seems like it's just
physics to me (yes, we're
at the limits of my understanding!).

thank you.







Re: Guidance w/ Tek 475

Mlynch001
 
Edited

Set all controls to the "mid Range" position. Leave the scope in "AUTO" Trigger. Set the time base to 1.0 mS and Volts to 5 V. introduce a 1Khz signal to the A channel and see if you get a trace. IF you get a trace, then set the amplitude so that the waveform fits into the vertical space of the CRT. Push the "normal trigger mode button and then adjust the trigger level until the scope locks on to the waveform.

Re: Guidance w/ Tek 475

Mlynch001
 

On Mon, Feb 12, 2018 at 11:08 am, n4buq wrote:


I don't know for sure, but it appears the INTENSITY control is fully CCW.
Have you tried increasing the intensity?

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "N0AGI" <n0agi@...>
To: TekScopes@groups.io
Sent: Monday, February 12, 2018 1:02:09 PM
Subject: Re: [TekScopes] Guidance w/ Tek 475

Yes, that was one of the steps - please see this quick YT video of what I am
seeing. I was discussing this w/ someone earlier, his suggestion was to
look into the sweeping circuit. I am not versed w/ repairing test gear. So,
I am also looking for someone or a repair shop here in the Minneapolis area
who can take a look at this and potentially discuss repairing.
https://youtu.be/y7W543oso18

if you are from the Minneapolis region, and willing to take a look at this
for troubleshooting and repairing (for a cost of course), please drop me a
note at n0agi@.... Thanks much

73s, N0AGI – Nagi
https://MNDMR.net/
https://N0AGI.com/

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of yoram
stein via Groups.Io
Sent: Monday, February 12, 2018 10:17 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Guidance w/ Tek 475

Check first  "Auto" knob is pushed in.

On Monday, February 12, 2018 1:39 AM, N0AGI <n0agi@...> wrote:


Hello everyone
I am new in this group.  I picked up a fixer-upper 475 for a good price
from
a local CL seller.  The unit is in an immaculate physical condition -
however, it has at least one problem that I know of.

The scope does not put out a trace.  When the "beam finder" is pressed, I
can
see the dot.  I then hooked up my FN Gen to the scope on ch1, and attached
is the output I see on the CRT when I hold down the beam finder.

I am hoping someone in this group can help with identifying the issue and
suggestions to possible fixes. I am not an expert in electronics by any
means - just a hobby enthusiast.  Consequently, if the fix requires a much
deeper work, I rather take it to a repair shop/person here locally in the
Minneapolis, MN area to get it fixed.  If it's something simple to ID and
fix, I would like to at least try to fix it myself.

Need guidance/help please.  Any pointers, YT videos to help w/ trouble
shooting, please advise

A couple of pics below

[cid:image002.jpg@...][Image]

Thanks all

Nagi
https://N0AGI.com/














Re: Guidance w/ Tek 475

Mlynch001
 

Your scope time base control in the XY Mode, all this will produce is a dot.

Re: Guidance w/ Tek 475

Mlynch001
 

Sent that Exact suggestion in yesterday and it still has not posted. I suppose that the Moderators must still be looking at my reply? As Brian said above. Best to download and completely read the manual to familiarize yourself as to how the scope controls work, before you damage the scope or assume that you need repairs. You could get stuck with a "repair bill" for something that did not need "repairs".

Tek 2430A - please tell me it's a good scope... :]

Marcin Marzeta
 

Dear Group,

My first post here. I'm in Poland and I design and build tube guitar amps.
I currently own a reliable 7603 and have recently started fixing my old 465 with DM44.

Yesterday I snapped and bought a 2430A. I think I really need built-in measurements as they make life easier. The problem is I'm not sure if I made a good choice... 2430A I bought looks fully working with all originall manuals and even probes, very good condition. So I'm actually looking for a general opinion on the model - is it a good one?

--
Marcin
marvelamps.com / 465 DM44 / 7603 / 2430A (on its way)