Date   

Re: I give up.

 

Paying with paypal from credit card is simpler, but doesn't work in this
case, so you're supposed to do the next simplest thing, which is top up via
wire transfer and then pay from balance. All this hacked companies paranoia
is seriously too much, and I say that as a cyber security expert who has
been professionally in IT for 20 years. I've seen and responded to
countless hacks and I know good security awareness is necessary. You're
talking about your bank and about paypal. If either of them get hacked then
you have much larger problems than whether or not you have the convenience
of being a git towards Dennis. Have it from the horse's mouth: you're not
being aware of potential problems, you're being unreasonably paranoid, and
you're cargo-culting security obviously without understanding any of it.
Stop it and just pay Dennis without dragging your feet.

On Fri, Dec 4, 2020 at 3:58 AM - <rrrr6789@gmail.com> wrote:

It's much simpler to just pay via PP and have them charge my credit card,
then there's never a balance in my PayPal account and if I haven't linked a
bank account to your PP account then they can't debit it either. A credit
card also has much better protection and you also have legal recourse if
things go wrong. These days, it isn't just PayPal that you have to worry
about, plenty of companies have been hacked and their client's data stolen.
The fewer companies that are linked and the fewer that have any of your
information including information about your other accounts, the safer you
are.

On Thu, Dec 3, 2020 at 12:05 PM cheater cheater <cheater00social@gmail.com
wrote:

Right, that's why you top it up with the amount you want to pay, and then
pay. You don't carry a balance - you top up, then pay immediately. Unless
you're some sort of criminal with an international warrant on your head,
money will not disappear from your account within one day. There's a
certain amount of paranoia that's healthy with online services, but there
are limits to reasonable application of that as well.

On Thu, Dec 3, 2020 at 1:53 AM - <rrrr6789@gmail.com> wrote:

George, It's already taken care of.


Cheater, FWIW I don't know anyone that carries a balance in their PP
account. Not only does PP not pay interest, but PP has been known to
yank
money back out of their customer's accounts without warning so everyone
that I know takes their money out of PP as soon as possible. Yes. I
know
that PP can also yank money out of their customer's bank accounts as
well.
Most people keep only a minimum amount in their linked accounts for
that
reason and keep their main bank account in a different bank entirely.

On Wed, Dec 2, 2020 at 9:11 AM George Onufer <amatec@att.net> wrote:

Mr. RigdonI am so sorry to hear of the tribulations you have endured
in
trying to buy these books.Dennis took on this task (beyond the
resposibility he already had as moderator) out of his respect and
sense
of
duty to the group. He established ground rules to make it manageable
for
himself. If, for whatever reason, these don't work for you, then by
all
means he should make a special exception in your case.GeorgeSent from
my
T-Mobile 4G LTE Device

















Re: Historical Analog Scope Triggering Techniques

 

Tom,

I have been considering just such an acquisition, but, until I can move my workshop to a larger space (that's on the list of things to do) there is no room for a computer, which has proven quite limiting on more than one occasion. Right now, however, I'm working within the confines of what I have to hand, and what would have been contemporary to the machine I'm trying to investigate (this is a hobby, and that's part of the fun).

My actual goal is to get a shiny, new DSO with an LA option (I'm planning to get a Siglent 1204), but that won't be till some time next year.

-- Jeff Dutky


Re: Tek 2236 and the CTM Board

 

Ah, I figured it out: by prying the right hand side of the extension away from the plunger, and then levering the left hand side with the blade of the spudger, and applying more force than I had thought safe, the extension lets go quite suddenly (and a bit distressingly). After you've done it a few times, however, you get used to the amount of force needed, and the proper angle to apply with the spudger. A diagram in the service manual would have been very helpful.

My apologies to Leo if that was what he was telling me to do. I misunderstood because of the use of the term "knob" rather than "button". I'm a terribly literal-minded sort, and it leads me astray all too often.

Next problem was removing the power supply cover, but that was merely a matter of find all the screws that held it in place (two recessed and one pan-head torx on the back, two pan-head torx on the bottom, one that holds the HV protective plastic cover in place, and one on the side), then wrestling it out of the case in close quarters (probably a lot easier if you've removed a the CTM board and the alternate sweep board). We will see if I'm able to get it back in place without first removing the CTM and alternate sweep boards (I kind of doubt it).

Finally it was a simple matter to remove the fan, peel off the hub sticker, and put some light oil on the end of the bearing shaft. We will see if that cures the loud fan noise, or if I have to order a new fan (a Matsushita PANAFLOW DC burshless, model FBP-06A12L, easily and inexpensively obtainable from at least one popular electronics retail site).

-- Jeff Dutky


Re: Historical Analog Scope Triggering Techniques

Tom Gardner
 

Consider buying one of the £20 logic analysers that use a USB
interface and the PC's screen. That (8 bits, 24MS/s) should be more
than enough to debug that kind of logic.

Key advantages of an LA are complex triggering and filtering, so you
only see the interesting information, not all the clutter.

On 04/12/2020, Jeff Dutky <jeff.dutky@gmail.com> wrote:
Okay, this is all in line with what I've been thinking about: building a
little box that can raise a TTL output on various conditions like a specific
counter bit, or having a 16 bit input value between two selected values, or
when certain bits are set or cleared, etc. It seems like this would make all
kinds of things visible on a simple analog scope at relatively little cost
(assuming that you don't want to do the triggering at clock rates much above
a few tens of MHz, of course).

One of the things that I was trying to do with these scopes, before I got
side tracked having to fix them, was to reverse engineer the digital
interface to a gas plasma display in an old laptop. Getting anything more
than a very general look at the display signals was very challenging,
especially since I didn't understand most of the scope's features very well,
but also because I just wasn't thinking clearly about how to trigger the
scope and one what. After working on these scopes for the past month I think
I'm beginning to get a better feel for what they can do and how they should
be used.

-- Jeff Dutky






Re: Tek 2236 and the CTM Board

 

Leo,

there is no knob here (or, rather, the was a knob in step 1, but I got that out without any trouble). These are pushbuttons that have a short extension that pokes through the front panel. The extensions are clipped around the pushbutton's plunger. It's clear that they can be separated somehow, but not clear how that can be achieved.

I have created this album https://groups.io/g/TekScopes/album?id=257515 (titled "2236 CTM Pushbuttons Disassembly") to illustrate the process and the issue.

-- Jeff Dutky


Re: Tek 2236 and the CTM Board

satbeginner
 

Nope, put the screwdriver vertical behind the side of the knob, push down on the screwdriver and use it as a wedge to push the knob towards you.

Away from the front, in the same direction as the axle.

Better to use two screwdrivers to keep everything in line.

If you push down on the knob itself you will break things....

Saludos,

Leo


Re: Historical Analog Scope Triggering Techniques

 

Okay, this is all in line with what I've been thinking about: building a little box that can raise a TTL output on various conditions like a specific counter bit, or having a 16 bit input value between two selected values, or when certain bits are set or cleared, etc. It seems like this would make all kinds of things visible on a simple analog scope at relatively little cost (assuming that you don't want to do the triggering at clock rates much above a few tens of MHz, of course).

One of the things that I was trying to do with these scopes, before I got side tracked having to fix them, was to reverse engineer the digital interface to a gas plasma display in an old laptop. Getting anything more than a very general look at the display signals was very challenging, especially since I didn't understand most of the scope's features very well, but also because I just wasn't thinking clearly about how to trigger the scope and one what. After working on these scopes for the past month I think I'm beginning to get a better feel for what they can do and how they should be used.

-- Jeff Dutky


Re: Tek 7854 intermittent issues

Nick Corvid
 

UPDATE

Been a while since my last post. Just today I have gotten the replacement capacitors for most of it's suspicious caps. I replaced the 1000uf on the auxiliary regulator board, and replaced all the 4.7ufs on all the removable boards and the aux reg. And honestly, there is practically no improvement at all which is supremely frustrating. Kind of back at square one again.

Does anyone have any advice?


Tek 2236 and the CTM Board

 

I'm trying to get in to a 2236 in order to lube or replace a noisy power supply fan, but I can't figure out how to disassemble the pushbutton extensions from the buttons. The service manual says:

"2. Remove the six buttons and extension shafts from the CTM switches by inserting a small screwdriver between the extension shaft and the switch shaft. Push down and forward until the extension shaft is disengaged and pull the shafts straight back through the front panel."

I'm perplexed by which way is up or forward in this paragraph. I have the scope sitting on it's belly (where the small rubber feet would be with the case on) and the front of the CRT facing me. Am I supposed to push "down" on the switch shafts from this position? Will they disengage from the extension shafts by sliding perpendicular to their normal direction of travel? I've tried to release the extension shafts several times with no success (and, fortunately, no damage to the switch shafts or extension shafts). I've tried different sizes of "small screwdriver" from a miniature screwdriver that would be suitable for adjusting the trace rotation or probe compensation, to a nylon spudger whose blade is about 6mm wide.

What am I doing wrong?

-- Jeff Dutky


Re: Historical Analog Scope Triggering Techniques

Clark Foley
 

There were other tricks using 7k plugins such as the 7D11 or the TM500 equivalent digital delay unit. I wasn't a word recognizer but you could delay by counting microprocessor/logic events such as clocks, interrupts, and such, and then trigger the scope. You might be able to stumble into a useful display by fiddling with the holdoff but it was not predictable or deterministic. You could also do odd things to trap narrow pulses, runt pulses and setup and hold violations as well using the gating controls of the 7D15 Universal Counter timer. The greatest addition to digital trouble shooting before multi-gigahertz DSOs, was the Micro-Channel Plate(MCP) analog CRT found in 7104, 2467 and 11302. The MCP tube could show you one bad event in a million without a camera!. (High writing rate film is too scary to introduce here!)

In the late 1980s, I used and shamelessly promoted the idea of using the 11302A with its holdoff by events, dual counters and MCP to not only see the nasty event but also quantify it up to 750MHz counting rate. You determine the error rate as small as 1 in 1E9. Maybe it was 1E10? You could do similar thing with 7D11, 7D15 in the 7104 with higher MCP performance but lower counter performance.

I shaved today; so, no grey beard!


165-2389-00 Hybrid Attenuator IC, TDS 400, New Old Stock

Ryan Scott
 

Greetings to the group, hope all of you are doing well, staying positive and testing negative!
I'm still going through the estate of a deceased collector of test equipment and recently came across a sealed bag from MAXTek dated Jun 2004 of these 165-2389-00 (H2389) hybrid ICs.  Google says they are used for the Tek TDS400 scopes.  But, no schematic to confirm that.  So, if you have one of these scopes, I have (what I believe to be) New old stock of these hybrid attenuator IC's.  The sealed package contains 20.  I'll keep 4 of them and offer the remaining 16 of them to the group at $35 USD (each) plus shipping costs.  Please email me at n7qj@arrl.net for pictures and additional details.  
Thanks and Regards, Ryan Scott
N7QJ


Re: I give up.

-
 

It's much simpler to just pay via PP and have them charge my credit card,
then there's never a balance in my PayPal account and if I haven't linked a
bank account to your PP account then they can't debit it either. A credit
card also has much better protection and you also have legal recourse if
things go wrong. These days, it isn't just PayPal that you have to worry
about, plenty of companies have been hacked and their client's data stolen.
The fewer companies that are linked and the fewer that have any of your
information including information about your other accounts, the safer you
are.

On Thu, Dec 3, 2020 at 12:05 PM cheater cheater <cheater00social@gmail.com>
wrote:

Right, that's why you top it up with the amount you want to pay, and then
pay. You don't carry a balance - you top up, then pay immediately. Unless
you're some sort of criminal with an international warrant on your head,
money will not disappear from your account within one day. There's a
certain amount of paranoia that's healthy with online services, but there
are limits to reasonable application of that as well.

On Thu, Dec 3, 2020 at 1:53 AM - <rrrr6789@gmail.com> wrote:

George, It's already taken care of.


Cheater, FWIW I don't know anyone that carries a balance in their PP
account. Not only does PP not pay interest, but PP has been known to yank
money back out of their customer's accounts without warning so everyone
that I know takes their money out of PP as soon as possible. Yes. I know
that PP can also yank money out of their customer's bank accounts as
well.
Most people keep only a minimum amount in their linked accounts for that
reason and keep their main bank account in a different bank entirely.

On Wed, Dec 2, 2020 at 9:11 AM George Onufer <amatec@att.net> wrote:

Mr. RigdonI am so sorry to hear of the tribulations you have endured in
trying to buy these books.Dennis took on this task (beyond the
resposibility he already had as moderator) out of his respect and sense
of
duty to the group. He established ground rules to make it manageable
for
himself. If, for whatever reason, these don't work for you, then by
all
means he should make a special exception in your case.GeorgeSent from
my
T-Mobile 4G LTE Device













Re: Peter Keller book payments PayPal won't release

Tam Hanna
 

Hello Damian,

sorry, but I do not sell these at all.


I only wanted to offer my services as a "bank" to ease Tilmans work load.


Tam

--
- - - - -
With best regards
Tam HANNA

Enjoy electronics? Join 13500 followers by visiting the Crazy Electronics Lab at https://www.instagram.com/tam.hanna/


Re: Historical Analog Scope Triggering Techniques

saipan59 (Pete)
 

This seems like a "purpose" for my old HP logic analyzers - use an LA to trigger on a complex logic situation, and the Trigger Output triggers the scope to show the analog situation.
[I've wanted an excuse to use a LA for something practical, but still don't really have a need in the projects I do.]

Pete


Re: Historical Analog Scope Triggering Techniques

Steve Hendrix
 

At 2020-12-03 01:18 PM, Dave Seiter via groups.io wrote:
Was it common practice, in the days before DSOs, to use purpose built external circuits (counters, random combinatorial or sequential logic) to trigger your scope to specific conditions?
I would often build a scope trigger into firmware, using a spare output pin as that trigger, and sometimes include an ability to command the trigger to indicate different events. One particular system done when I worked for a NASA subcontractor, included a very complex multiplexing system for sensors, with programmable filter selections, etc. I set it up so the console could ask to watch a particular sensor channel, and the firmware would fire the trigger just before beginning the setup for that channel, allowing the scope to display exactly what was going on during the switching and settling to the new channel. It ended up being pretty cool that I could be sitting in another room or even another building (this was before the Internet was widely used), and could switch the technician's scope between channels remotely. This was back in the 1980's long before we had all the fancy debugging features built into todays microcontrollers.

Steve Hendrix


Re: Historical Analog Scope Triggering Techniques

Tom Gardner
 

On 03/12/20 15:42, Jeff Dutky wrote:
Was it common practice, in the days before DSOs, to use purpose built external circuits (counters, random combinatorial or sequential logic) to trigger your scope to specific conditions?
Yes, repeat no - depending on what you include in "external".

I've added outputs to equipment I've built that were used to trigger whatever test equipment was attached.

External equipment was often used to trigger sequences in a unit under test, and that can also trigger test equipment.

But the overriding principle I've used is "analogue test equipment for analogue waveforms, digital test equipment for digital signals". That implies:

* use scope to check the analogue waveforms will be correctly interpreted by
receivers (e.g. standard logic) as digital signals. That's just ensuring the
"signal integrity"
* once you have signal integrity, flip to using logic analysers and printf()
statements to capture and debug digital signals


Re: Historical Analog Scope Triggering Techniques

Dave Seiter
 

The 7A42 goes down this road, as it triggers on 4 bit logic.  Always wanted one, but have never needed one.
-Dave

On Thursday, December 3, 2020, 07:42:51 AM PST, Jeff Dutky <jeff.dutky@gmail.com> wrote:

Was it common practice, in the days before DSOs, to use purpose built external circuits (counters, random combinatorial or sequential logic) to trigger your scope to specific conditions?

Seeing the P6406 word recognizer probe, which looks like just such an external bit of combinatorial logic professionally packaged, got me thinking about this. I had assumed, on first reading about the P6406, that it was specialized probe that would only work with specific scopes (and I'm still not sure if that's the case; it seems to be mentioned in connection to a range of 2400-series scopes), but it looks like it just produces a rising/falling edge signal and you are supposed to stick a regular passive probe in the output end to trigger off that signal. It seems like triggering off other bits of external logic (e.g. the rising/falling edge of a specific bit from a counter) would be very useful in diagnosing digital/binary circuits with an analog scope, especially if that scope were an analog storage scope.

Was this sort of thing common practice? What was the range of techniques used?

(yes, I'm looking for greybeard stories, but also trying to expand my meagre diagnostic skills)

-- Jeff Dutky


Re: Point contact diodes like 1N416 family

Miguel Work
 

Check voltage in diode mode with 1k resistor and you will know current test. After that check curve https://pdf1.alldatasheet.es/datasheet-pdf/view/655603/NJSEMI/1N416D.html

Usually current in diode mode is about 0,5mA for a Fluke to 1mA in standard multimeter. . If is 1mA with 1k resistor you will see 1v

-----Mensaje original-----
De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de snapdiode via groups.io
Enviado el: jueves, 3 de diciembre de 2020 18:41
Para: TekScopes@groups.io
Asunto: [TekScopes] Point contact diodes like 1N416 family

These diodes are historical and quite ancient, so of course they show up in some Tek stuff like spectrum analyzer plugins.

From what I understand they have a low Vf, but also a very low reverse breakdown voltage. Is this correct? I've looked at some datasheets and the graphs don't show the reverse voltage.

So testing a diode with a modern DMM what should I expect to see in diode mode?

I have a 1N416D that reads about .13 volts forward and about .4 volts reverse. This seems like it would work for the limited dynamic range specified for the specan.

I need to start troubleshooting somewhere and the 1L20 is another one of these 1s1-style monsters to troubleshoot. I have a 1N416E NOS diode too but it's still in its sealed bag, I don't want to open it! (Yes it's silly but I am a very silly man)







Scanned by McAfee and confirmed virus-free.
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Re: Point contact diodes like 1N416 family

Carsten Bormann
 

On 2020-12-03, at 18:41, snapdiode via groups.io <snapdiode=yahoo.com@groups.io> wrote:

These diodes are historical and quite ancient, so of course they show up in some Tek stuff like spectrum analyzer plugins.

From what I understand they have a low Vf, but also a very low reverse breakdown voltage. Is this correct? I've looked at some datasheets and the graphs don't show the reverse voltage.
“The reverse voltage” does not exist for Ge diodes.
This figure would always need to be measured at a specific current.


So testing a diode with a modern DMM what should I expect to see in diode mode?
That’s the problem: DMMs vary wildly in what voltages (or, better, currents) they use in diode mode.
You get the best information if you can test a range of currents, several orders of magnitude.

I have a 1N416D that reads about .13 volts forward and about .4 volts reverse.
This looks like the DMM tests at a low current (microamps).
Or the diode is really shot.

Grüße, Carsten

This seems like it would work for the limited dynamic range specified for the specan.

I need to start troubleshooting somewhere and the 1L20 is another one of these 1s1-style monsters to troubleshoot. I have a 1N416E NOS diode too but it's still in its sealed bag, I don't want to open it! (Yes it's silly but I am a very silly man)





Re: Historical Analog Scope Triggering Techniques

snapdiode
 

The 74LS688 can be used to make a word recognizer.

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